auckland council road charging options study: scheme...

Auckland Council

Auckland Council Road Charging Options Study: Scheme Design and Costing

Vehicle Detection and Identification Technology

1 October 2014

Part B.1. Vehicle Detection and Identification Technology, Draft 20/9/14

Table of Contents

1. Introduction 1

2. Technology overview 2

3. Preferred technologies 12

4. Roadside high level design 23

5. Maintenance and renewal assumptions 28

6. In-vehicle requirements 31

7. Conclusions 32

Annex A – Scope of Deliverable B.1 Technology 34

Annex B – Illustrative designs for the roadside technology 35

Annex C – Motorway charging scheme – main highway gantries 43

Annex D – Illustration of a Wider Cordon Scheme46

Annex E – Gantries vs Side-Mounted Poles and Cameras 49

Annex F – Entry or Exit Charging on Motorways 53

Part B.1. Vehicle Detection and Identification Technology

Glossary

Abbreviation Definition

ANPR Automatic Number Plate Recognition

CCD Charge Coupled Device

DSRC Dedicated Short Range Communications

GNSS Global Navigation Satellite System

GPS Global Positioning System

OCR Optical Character Recognition

RFID Radio Frequency Identification

V2I Vehicle to Infrastructure

V2V Vehicle to Vehicle

Part B.1. Vehicle Detection and Identification Technology 1

1. Introduction

1.1. Purpose of this document

This document sets out an analysis of technology options and their relative strengths and

weaknesses for the scheme options being considered for road charging in Auckland. Annex A

describes the terms of reference for this report.

1.2. Road charging scheme options

In summary the road charging options being considered for Auckland are:

• A motorway charging scheme

• A cordon-based scheme.

Further details of these schemes are set out at Annex B.

1.3. Structure of this document

Section 2 provides an overview of road charging technologies including emerging solutions.

Section 3 proposes preferred technologies identifying the items that are yet to be validated and also

subject to the charging policy of each scheme.

Section 4 provides an indicative roadside design – this is independent of specific supplier products

which may vary the dimensions and capability of the solutions.

Section 5 addresses the maintenance and renewal requirements in general. Individual supplier

products will have differing maintenance requirements and failure rates. At this stage no supplier

solution has been selected.

Section 6 addresses in-vehicle technology requirements.

Section 7 summarises our conclusions on technology.


2. Technology overview

2.1. City schemes/Cordon

Most city schemes (like Auckland) have many access points and rely on cameras to detect vehicle

movements. The most commonly used alternative technology for tolling purposes is tag and

beacon - or Dedicated Short Range Communications (DSRC) – but this has been used primarily to

automatically raise toll plaza barriers (for example, in Oslo, Trondheim). More recently however,

improvements in ANPR have meant that it has become the preferred technology for detecting

vehicles accessing city schemes with toll plaza barriers being removed to allow for “free flow”

conditions.

Developments in optical character recognition (OCR) technology, illumination, vehicle triggering and

tracking, spatial recognition, back office processing and filtering out misreads mean that read rates as

high as 98-99% using ANPR are now feasible. By comparison DSRC tag technology can theoretically

deliver read rates of up to 99.8%; however other human and vehicle related factors can reduce

accuracy, making the overall performance only marginally better than ANPR, when optimally

implemented. But there are also a wide range of factors that can reduce ANPR read rates to

substantially less than DSRC tags. Table 1 indicates elements that contribute to misreads for both

ANPR and DSRC technologies.

Table 1: Factors that affect ANPR and DSRC reads

Items that contribute to plate misreads/errors Items that contribute to tag misreads/errors

• Obscuration by high-sided vehicles

• Dirty and broken plates – particularly rear plates on trucks

• Lighting and sun blinding effects

• Camera mounting arrangements

• No visible front plates on motor-cycles

• Vehicle is on wrong side of road outside camera field of view

• Heavy rain or snow

• Tag has not been fitted correctly

• Tag battery has failed

• Metallised windscreens

• Tag fitted to incorrect vehicle

• Vehicle is on wrong side of the road outside detection area

Hence, for a city scheme, where there is also a need to support occasional users without a tag, and

cameras are still required to gather evidence on non-payers, ANPR can be a more cost effective

option even without considering other factors. The use of tag and beacon technologies is therefore

largely an additional cost that can only be justified if there is strong business case for improved

detection rates. Given the additional cost of issuing and managing tags; this is usually where multiple

detection events are needed to calculate the charge due (for example a distance-based scheme).


Table 2 summarises the technologies adopted by comparable schemes reflecting early use of tags

and increasing adoption of ANPR.

Table 2: Technology adopted by city charging schemes

City Scheme and technology When implemented

Singapore Paper Area Licence 1975

Bergen Cordon: Autopass Tag with toll plaza 1986 manual tolling; electronic from 2004

Oslo Cordon: Autopass Tag with toll plaza From 1991

Trondheim Cordon then area: Manual payment (toll plaza) or Autopass tag

1991 cordon, then area from 1998

Singapore ERP Area: DSRC tag/on-board device 1998

London Area: ANPR detection Feb 2003

Durham Area: Barrier based payment initially, then ANPR based detection

2002

Stockholm Cordon: ANPR with tags from 2006, then just ANPR from 2007

Trial from 2006. Full operation: 2007. To be extended in 2016.

Milan Area: ANPR detection Jan 2012 following the earlier Ecopass environmental zone, 2008 onwards

Gotenborg Cordon: ANPR with a shared back office with Stockholm to minimise costs and delivery risk

Jan 2013

Note the increased use of ANPR-based detection in cities as this technology has improved.

2.2. Motorway schemes

Motorway/expressway tolling schemes are typically quite different and may involve a series of

charges being applied by section. They typically use a mix of technologies including ANPR, DSRC

tags and GPS systems. The majority of GPS-based systems implemented to date are for heavy

goods vehicle charging.

Table 3: Examples of motorway charging/tolling scheme technology

Scheme Technology When implemented

Liber-t: French Autoroutes Tags and manual payments with barriers 1980s

Italian motorways Tag and beacon with barriers 1990

Dartford Crossing, UK Manual payment (toll plaza) or Dart tag until Nov 2014 – when it will move to ANPR-based detection

1991

Toronto ETR 407, Canada Cameras and tag and beacon – open road with gantries 1997

ERP, Singapore Electronic OBUs – open road with gantries 1998

Melbourne City Link, Australia Went live with tag and beacon DSRC with video tolling payments for occasional users – open road with gantries

2000

M6 Toll, UK Barrier-based with manual payments and tags 2003

Salik, Dubai Tag and beacon with RFID OBUs (ISO 18000 6B) and gantries

2007

Dublin M50, Ireland Tag or video payment account or occasional user video payment with gantries

2008


Scheme Technology When implemented

Golden Ears/Port Mann Bridges, Canada/US

Tag and beacon with RFID OBUs (ISO 18000 6B) and more recently 6C tags + video tolls on gantries

2009 Golden Ears

2012 Port Mann

Northern Gateway, NZ ANPR-based detection mounted on gantries 2009

Gauteng Freeway Improvement Project South Africa

Tag and beacon with camera enforcement on gantries 2012

Distance based charging schemes have been primarily implemented for heavy goods vehicles and

include those set out in Table 4.

Table 4: Summary of distance charging schemes

Scheme Technology When implemented/status

Swiss LSVA Tachograph/GNSS with manual enforcement

2001

Austrian Maut DSRC Tag and beacon with camera enforcement

Jan 2004

German Maut GNSS with camera and infra-red DSRC enforcement

Originally due in Aug 2003, but delayed by technical failures until Jan 2005

Czech Truck Toll DSRC Tag and beacon with camera enforcement

2007

Slovak Skytoll GNSS with DSRC and camera enforcement

2010

Poland: HGV charging DSRC Tag and beacon with camera enforcement

July 2011

French Ecotaxe GNSS with DSRC and camera enforcement

Scheme was suspended pending political decisions (Oct 2013) but will now go live in early 2015 on a partial basis

UK HGV Levy Paper-based vignette April 2014

Belgium HGV Charging - ViaPass

GNSS with DSRC and camera enforcement

Due to go live in 2016 for trucks. Original plan included a vignette for cars from 2018, but this element has now been postponed.

2.3. Technology developments

Key developments in tolling and charging technology include:

• Improvements in number plate recognition techniques and the associated availability and

quality of vehicle registration data held by national motor registrars;

• Improvements in roadside vehicle spatial tracking and classification devices;

• Reductions in cost of roadside equipment, for example:

− Camera equipment moving from 1” or ¾” to ½” charge-coupled devices (CCD);

− Developments in electronics, solid state technology, and reducing size and costs of storage

and processing power so that the computer analysis is now in a device on the roadside pole

or gantry instead of in a cabinet or datacentre without disk drives or moving parts;


− Integration between licence plate readers and cameras to create a single unit; and

− Improvements in DSRC tag reader technology,

• Reduction in unit costs of DSRC electronic tags through mass production to bring costs down

towards $15-$20;

• Developments in RFID technology – widely used in the US - to bring RFID tags towards a cost

of $1-$2;

• Improvements in GPS-based devices (e.g. shorter time to first fix, use of confidence data to

rule out rogue fixes) and reductions in unit costs towards $100 and increasing numbers of

satellites overhead to enable positioning fixes.

The primary emerging technology is the vehicle to vehicle (V2V) and vehicle to infrastructure (V2I)

standards which have adopted the 5.9 Hz WAVE standard for communications between vehicles and

with the roadside. Tolling or charging is just one “app” amongst a wide range which V2V and V2I are

expected to support in the next 15-20 years, summarised in Table 5 below.

Table 5: Summary of applications which V2V and V2I are planned to support

Safety

• E-call to a tunnel control room or 111 service

• Warnings on entering or leaving tunnels and at highway intersections

• Obstacle discovery and alerting

• Warning of sudden traffic braking and stopping

• Reporting incidents and accidents

• Lane change warnings

• Highway edge/ tunnel wall impact avoidance

Traffic Management

• Variable speed limits and intelligent speed adaptation

• Adaptive signal control/priority

• Automated intersection control

• Priority for ambulances, fire and police cars

V2V

• Collision avoidance (front to rear and front to front)

• Spatial monitoring of the vehicle relative to other vehicles: trajectory, relative distances, speed of surrounding vehicles.

• Recording accident details (black box)

Driver Assistance

• Guidance to parking locations and destinations

• Parking a vehicle

• Cruise control

• Support to keeping in lane

• Electronic road sign recognition/repeating

Control and Enforcement

• Traffic surveillance

• Speed limit warnings

• Access control and restricting entry

• Checking vehicle/driver credentials/load details

• Commands to pull over

Payments

• Toll collection

• Parking payments

• Freight/loading control

• Usage based insurance

Information

• Maps and navigation

• Fuel stations/electric charging points

• Business locations

• Car related services

In practice, V2V and V2I standards are some way from being implemented in vehicles available today

and there is likely to also be a substantial legacy vehicle fleet on the road even when these solutions

are fitted as standard to new vehicles.


This technology was recently demonstrated at a technology trade show (Computex, Taipei, June

2014) but vehicle manufacturers have not yet committed to a timeline for when this capability will

become part of a standard vehicle fit. Most commentators regard this technology as being over 10

years away.

The one element that may be relevant in the short term is the 5.9 GHz WAVE standard which some

tag and beacon suppliers have adopted to increase the communications range between the tag

reader/beacon and tag/OBU from the ~10 metres allowed by the CEN 5.8 GHz standard, towards 70

metres or more.

2.4. Manual or paper-based schemes

Some cities have used or considered paper or manual based schemes where a paper ticket or

vignette is issued to demonstrate a driver has paid a charge; this can then be inspected by an

enforcement officer. Singapore operated an Area Licence Scheme in this manner between 1975 and

1998. A paper scheme was also explored as an option for London by the ROCOL 1 study. In general

they have only been applied to area schemes or where a blanket charge applies to use roads on a

particular date or period of time, like the vignettes operated for heavy vehicles in Europe.

Our research indicates that the substantial majority of such schemes have become automated in the

past 15-20 years using technology. The primary reasons have been to reduce operating costs,

improve data capture and allow users to have simple-to-operate accounts instead of paying for a

manual ticket each day or period. The only paper based system still operating is in Switzerland where

vignettes are compulsory on all national class 1 and 2 roads. There is only the 1-year vignette valid

from 1 December of the preceding year until 31 January of the following year, i.e. 14 months. The

vignette price does not include driving through the Grand St. Bernhard Tunnel and Munt la Schera

tunnel where a special toll must be paid. The Swiss vignette price is €33 so it can be regarded as

form of levy. It is enforced by the police.

Paper based approaches don’t assist in vehicle detection for either a motorway scheme or a cordon

crossing, although a receipt can be issued where the user “declares” that they have used the

motorway or crossed a cordon. We don’t consider a manual or paper-based solution to be

economically feasible and do not consider it further.

2.5. Suitability of GPS

GPS devices are now widely used for satnav and telematics in vehicles, and in theory these same

devices could be used for road charging. Although GPS is quite a mature solution for navigation and

distance measurement it has a high unit cost in comparison to other OBU options. Also, it is only

accurate insofar as visible satellites, on-board signal processing mapping and back office corrections

permit. These factors generate a range of complexity, cost, installation and approval issues. For

example:

a) To position a vehicle the GPS unit needs to have unobstructed view of a minimum of 4 GPS

satellites in the sky (effectively 3 to provide position in 3 dimensions and a 4th to resolve

timing). On the open road and motorways this is not a significant problem. Hence, many of

the motorway-based charging schemes in Europe and the Heavy Vehicle RUC tax in New

Zealand rely on GPS devices. In urban environments buildings can block the view of the sky

making positioning less accurate. Most satnav devices compensate by having an on-board

1 The Review of Charging Options for London (ROCOL) working group, Government Office for London, March 2000


road map – but this increases complexity and storage requirements and requires the map to

be kept up to date through data downloads.

b) There are signal processing standards for GPS (NMEA data) which allow the quality of a

position reading to be assessed, so that incorrect or low quality data can be discarded.

However, not all chipsets and implementations of available chips make this data available to

the on-board processor – largely because for mass produced basic satnav or telematics uses

such data is not important.

c) To compensate many GPS tracking devices also incorporate a motion-sensor (or

accelerometer) which detects continuing movement and speed and can be used to “fill in the

gaps” where GPS position data is not available and corroborate GPS data. This again

increases the cost and complexity of the device.

d) When initially powering up, a GPS device has a time lag to initially capture its position; this

“time to first fix” can mean the start of a journey may be missed.

e) Where a vehicle is parked underground or for long periods the on-board device needs to store

its last position to accurately determine a starting point – most satnav products don’t do this,

but rely on satellite visibility at the start of the journey.

f) There needs to be a means of gathering journey data off the GPS device to send to the back

office – this is typically done with a mobile communications module running GPRS, 3G or

similar, with a SIM card. This further increases the operating cost and complexity of the

device.

g) The device needs an electricity source as GPS and mobile communications are power hungry

– as a result battery technology (in comparison a DSRC tag battery can last 7-8 years) is not

suitable. The device needs to be installed/plugged in to a power source in the vehicle; using

the “lighter” socket is not sufficiently reliable to ensure the device is always on.

h) For the device to be regarded as “evidentially robust” to support enforcement it would need to

be “type approved or gazetted”. In practice many of the issues of the validity of the position

evidence can be resolved through a customer contractual agreement that they will rely on the

device for measurement. However, if GPS position data was challenged in a court of law

general consensus is that it does not have the same evidential robustness as, say, a

photograph of a vehicle. It may also be impractical for an enforcement authority to inspect a

GPS device for its correct installation and operation (requires powers to enter the vehicle;

also data captured and status may be transitory, though this can be compensated for by

adding logging and security at additional cost). Hence the vast majority of GPS-based

charging schemes rely on image evidence for enforcement, for example, the German Maut

Heavy Vehicle Charging Scheme (live in 2005) and the planned Belgian Viapass scheme

(due to go live in 2016).


i) Tests of GPS based devices have demonstrated that where fine judgements of position are

required data quality is not sufficient:

• A vehicle driving just a few metres outside a cordon boundary may sometimes be

erroneously positioned inside and therefore deemed to have crossed the cordon

(see TfL’s technology trials from 2003-20082);

• A parked vehicle close to a cordon boundary may be detected as being located a

few metres away as the GPS signal wavers. A cordon may need a “buffer zone”.

j) Repeatability of a charge has also been challenging as the same journey repeated multiple

times may be measured as having slightly different distances depending on the GPS data

quality at the time. For this reason most GPS charging schemes divide the road network up

into a set of “zones” each of which has a charge unit. For example, the minimum zone size

used for the German heavy vehicle scheme (the Maut) was a 90m section of motorway

carriageway (or ramp), as there was a risk that smaller units might not be reliably detected by

the GPS on-board unit as the truck travelled on it. This enables a back office to apply a

charge for each zone without the actual distance travelled needing to be measured.

The existing Heavy Vehicle RUC scheme in New Zealand relies on a set of certified devices, which

don’t suffer from some the accuracy issues listed above. They have been tested to deliver sufficient

accuracy for tax collection to measure vehicle miles travelled on public and private roads. These

devices have a high unit cost and are typically used for a range of services including fleet vehicle

management, dispatch and tracking. There is an ongoing charge for the communications. A number

of service providers collect vehicle movement data, agreeing to keep that data private and administer

the collection of the tax.

To precisely locate a vehicle on a particular road, they use their own map data; at present we

understand there is no single reference map of GIS data that could be used as common platform for a

charging scheme across multiple types of GPS device. If the road charging option being considered

for Auckland was limited to a Heavy Vehicle scheme, the current RUC system may be a suitable

option for gathering charging data. However, for mass market vehicle charging, we don’t believe it is a

viable solution because:

• The GPS unit complexity leads to a relatively high unit cost, though costs continue to fall. A

GPS device with fitting and communications may have a minimum capital cost of the order of

$100 with a $5-$6/month operating cost (substantially higher than the 7-year life of a DSRC tag

at ~$25).

• The devices are not fitted on all vehicles as part of standard build and are not inspected on an

annual basis.

• The position data is not evidentially robust for a cordon scheme.

• ANPR cameras are still required for enforcement.

For a national distance-based charging scheme GPS solutions may be cost-effective; however there

are unlikely to be sufficient economies of scale for a local motorway scheme in Auckland.

2 J. Evans, N. Patchett, N. Williams, and A. Kowalski. Assessing the use of GPS for congestion charging in London. Traffic engineering & control, 46 (3):pp. 98.


Some of these factors can be overcome if the same device is also used for other applications (usage

based insurance, e-call, vehicle telematics) and there is an agreement with the customer that they will

be charged on the basis of what the on-board device measures (even if the data gathered may be

slightly incorrect). For comparison, most vehicle odometers are only calibrated to be +/- 4% accurate.

GPS is likely to mature when these the devices are fitted as standard to all vehicles and when costs

reduce.

2.6. Suitability of RFID tags

Like DSRC, RFID technology provides a tag-based solution for identifying vehicles where the tag is

fitted correctly. The main advantages of RFID technology are:

• The tag can be produced much more cheaply than for DSRC – a raw unit cost of $12 for a

DSRC tag might compare with a $1-$2 RFID tag cost making the device almost disposable and

reducing the need to manage the tag as an asset.

• The tag is essentially like a sticker that can be applied to the windscreen. Its slim profile means

that an envelope can be used, simplifying packaging, allowing delivery through letter boxes,

and reducing fulfilment costs.

The main disadvantages are:

• RFID has a less defined and focused radio coverage “footprint” than DSRC – but this may not

matter on a motorway access ramp.

• RFID detection typically requires a large number of antennae to be fitted to an overhead gantry

and may also need additional support from laser triggers and cameras subject to location

design. Figure 1 below illustrates how vehicles passages are detected at Port Mann using a

dual gantry arrangement, front and rear plate reading, loops, lasers and RFID tag reader (see

step 5).

Figure 1: Port Mann vehicle detection passage sequence


RFID is widely adopted for expressway tolling in the US, Taiwan, the Philippines and Turkey and is

being introduced on some river crossings in the UK, primarily to reduce operating costs.

In Auckland, it is unlikely to suit any cordon-based scheme because of the gantry-based infrastructure

required at a detection site, but for a motorway scheme it may provide some operational cost savings

and reduce the setup cost for a user account, in comparison with DSRC tags. However, the

implementation cost per access and exit point is likely to be greater than for DSRC to cover the more

complex gantries and detection equipment. The higher capital cost is likely to be offset by the reduced

operating cost provided there is high take-up of RFID tag accounts.

2.7. Potential solutions

Based on the review above there are four potential technology solutions from which to select options

for Auckland Road Charging:

• ANPR with cameras - for motorway or cordon

• DSRC tag and beacon – for motorway or cordon

• RFID tag and beacon – for motorway only

• GNSS/GPS for motorway only, although this likely to be uneconomic for passenger cars. It

could be a feasible solution for Heavy Vehicles where a distance-based charge in Auckland

was applied.


Table 6 compares the solutions in the context of the Auckland road charging options.

Table 6: Comparison of solutions in context of charging option

Motorway Scheme City Cordon Scheme

ANPR • Already used on Northern Gateway successfully

• Achieving read rate of 97-99% after manual and other checks

• Cameras required anyway for enforcement

ANPR + DSRC • Proven in many countries on expressways/motorways

• Infrastructure may be challenging to place on local residential roads

DSRC • Will not meet occasional user need

• May not meet evidential or enforcement requirements

• Likely to be high volumes of casual users so will not be the only solution required

ANPR + RFID • May reduce operating costs in comparison with an ANPR and DSRC scheme

• Infrastructure unlikely to fit on local roads

RFID • Will not meet occasional user need

• May not meet evidential or enforcement requirements

• Infrastructure unlikely to fit on local roads

• Requires all vehicles to be fitted so will not suit casual users

GNSS/GPS • Can deliver distance based charging

• Will not meet occasional user need

• High cost of OBU $100+ operating costs.

• Evidential nature not clear

• Though established for many telematics apps for hauliers, many HGVs don’t have it. Still to mature as car system integrated with e-call, Usage-Based Insurance and other apps.

• Though many fleets use it to calculate road usage charges for heavy rigid vehicles the payment of such charges is unrelated to the intended road charging scheme.

• Not sufficiently accurate to measure cordon crossing down to a few metres

• May not be accurate/ reliable enough for trips encroaching inside the boundary of over 50m

• Risk vehicles outside are positioned inside occasionally due to GPS errors

Of these options, GNSS/GPS requires relatively expensive in-vehicle equipment and in our

experience it is only suitable for national road charging schemes. We therefore discount it as an

option for a scheme in Auckland. Also, DSRC and RFID by themselves are not options.


3. Preferred technologies

3.1. Key requirements for technology choice

The key issues and challenges for the technology options identified in section 2 are summarised in

Table 7.

Table 7: Summary of key issues for Motorway and Cordon roadside equipment and charging policy

Motorway Cordon

Equipment Issues

Roadside equipment installation

The equipment needs to be capable of:

• Being located on the (multiple) access and exit ramps

• Being maintained safely

The equipment needs to be capable of:

• Meeting aesthetic and ‘streetscape’ expectations on the adjoining residential roads along the boundary

• Being located between driveways, trees etc.

• Fitting with complementary measures on adjoining roads: parking restrictions, segregation of carriageways

• Differentiating between journeys starting or ending at premises just inside or immediately outside the cordon

• Meeting stakeholder expectations and reaction to the proposed equipment

Number of installations required

~ 190- 200 sites for all access (105-115) and exit (75-85) ramps

~ 40 sites

Charging Policy Parameters

Need for multiple captures per trip

Capable of detecting access and exit events to calculate distance

Capable of detecting each cordon crossing

Detection/ read rate

Typically required to be 98-99% or better Typically required to 98-99% or better

Account holders Could be video/ANPR or tag based Could be video/ANPR or tag based

Occasional users Could use video based payment (like Northern Gateway)

Could use Video based payment (like Northern Gateway)

Direction of travel Simple to provide as carriageways already segregated

Requires lane segregation

Distance charge Could be calculated by entry and exit N/a

Time of day Could be calculated on entry time or exit Peak and off-peak often required

Class of vehicle Assumed to be based on registration lookup

Based on registration lookup

Evidence capture Camera based Camera based


3.2. Charging policy and need for multiple accurate captures

The simplest charging policies applied are typically:

• An access charge – for example for a motorway network

• A daily charge - for example in a city.

These policies only require a vehicle to be detected as:

• They access, use or leave the motorway

• They access, drive within or leave the city.

As a result for these simple schemes there is no requirement for multiple successive accurate vehicle

identification events to measure where or when they entered, moved around or exited. Indeed they

are intentionally designed to avoid this need. The technology used for detection can therefore be set

up to capture a minimum of one successful “read” out of a potential series of “read” opportunities. This

means the detection equipment can be implemented in a simpler and potentially less expensive

manner. For example:

Table 8: Examples of Charging Policy and Detection Requirements

Example Charging Policy Detection Requirement

The London Congestion Charge is a single charge that applies for the day irrespective of the number of times that cameras may detect the vehicle on the day.

In London a vehicle is typically detected ~3 times over the day by cameras on the boundary or inside the area. Assuming a detection rate of say 95%; for the vehicle not to be captured during a single “passage” at all over the day, statistically the number-plate would need to be within the 5% unread on each of the three occasions over the day – which has a combined probability of 0.053 = 0.01%.

The Milan Area C charge is a single charge for the day irrespective of the number of times that a vehicle enters or leaves the zone.

The driver is also required to “activate” the payment made whether the cameras detect the vehicle or not – a declaration scheme.

Assuming a vehicle is ‘seen’ by cameras at least twice a day, with a detection rate of 95%, the combined probability of not being detected is 0.052 = 0.25%.

The additional “self-declaration” aspect provides an additional detection layer.

As a result, it is acceptable to have cameras set up to, on average, only detect vehicles with a 95%

read rate. In practice, some camera sites may perform better than this – typically up to 98%; others

may be lower (~90%).

A slightly more complex variation may be to have a maximum daily charge following multiple

detections.

Other types of charging policy may require multiple accurate captures, for example, as in Stockholm

and on ETR 407 in Toronto.


Table 9: Other examples of more complex charging policy and detection requirements

Example Charging Policy Detection Requirement

The Stockholm Congestion Tax is based on cordon crossing events – a charge of 10, 15 or 20 SEK is applied for each crossing

Each individual crossing event needs to be recorded. Detection is claimed to be in excess of 98% with ANPR supported by manual checks.

ETR 407 in Toronto charges by km travelled, time of day and class of vehicle

As the vehicle accesses and exits the motorway the vehicle registration, time of day and location, as a minimum must be captured reliably. Detection rate is claimed to be in excess of 99% using tag and beacon and ANPR, supported by manual checks. Figure 2 illustrates the detection infrastructure.

Figure 2: Examples of detection infrastructure for single opportunity capture

ETR 407 Single Lane Exit Ramp Detection

Infrastructure (Dundas Street Interchange)

(Source: Google, 2011) Stockholm Camera Detection Point

The leakage rate on ETR407 (un-billable trips – including exempt vehicles) was quoted as falling from

3.8% (2007) to 2.4% (2013) as improvements in camera and detection technology have been made

and more customers have taken up tag accounts (source: 407 ETR, Feb 2014). The majority of

unbillable trips are by exempt vehicles.

ETR 407 has a number of similarities with the proposed motorway charging scheme:

• Comparable length – 100km

• Similar number of access and exit ramps (190 vs 198).


3.3. Cordon

There are two technology options for a cordon scheme:

• ANPR Cameras

• ANPR Cameras + DSRC tag and beacon.

Where a cordon is located on urban and residential roads the key challenge is locating the

infrastructure needed to mount the equipment. For DSRC + ANPR, the gantries typically used are

quite substantial and have a negative impact on the streetscape. ANPR cameras can be mounted at

the side of the road in a less obtrusive manner but their detection performance may not be sufficiently

high to enable a cordon-based charging policy unless it is considered acceptable to have:

a) Revenue loss/non-detection of the order of 4-8%

b) Risk of false positive plate reads.

In this situation there is a choice of three options:

1. Use cameras at the roadside and accept the reduced detection performance and revenue

loss that results. To compensate, the charge level could be increased to offset the possible

leakage, which may be of the order of:

a. 2-4% if the cameras can be set up overhead

b. 5-8% if the cameras are mounted at the side of the road

2. The cordon becomes an “area” scheme and ANPR cameras are used to monitor vehicles

driving in the area – the charge would therefore apply for the day across the area; or

3. ANPR and DSRC equipment is mounted overhead on gantries and cantilevers. Some

aesthetic design approaches can be used to reduce the visual impact but the equipment is

still substantial. On main intersections and highways the impact may be acceptable; on

smaller residential roads the impact may be more significant.


Differences in cost, risk and revenue are summarised below.

Table 10: Relative risks of the technology options for a cordon scheme

Risk/Differentiator 1. Cordon with ANPR 2. Area with ANPR 3. Cordon with ANPR + DSRC

Locating equipment Medium Low

High

Streetscape/ risk of acceptance of infrastructure by stakeholders

Medium-High

(appearance of equipment)

Medium High

(size and scale of equipment to be located)

Detection data quality risk Medium-High Low

(subject to mounting)

Low

User understanding risk Medium Low- Medium Medium

Roadside capital cost Medium-High Medium High

Impact on revenue Medium

(risk of missed transactions)

Medium

(subject to a daily charge applying)

Low

Impact on charge payers Medium High

(movements inside the boundary are charged)

Medium

Technical complexity Medium Low High

Figure 3 illustrates an example configuration for a camera-based detection point.

Figure 3: Illustration of Camera Installation for 2 lane Highway from Roadside Pole


3.4. Motorway

Access and exit ramp detection

There are three technology options for the proposed Motorway scheme:

• ANPR Cameras

• ANPR Cameras + DSRC tag and beacon

• ANPR Cameras + RFID tag and beacon

The latter two require quite similar infrastructure.

It is assumed that equipment would be placed on each access ramp and exit – estimated to be some

190-200 locations. There would be a substantial cost associated with this.

Figure 4 illustrates a pole mounted version for an ANPR solution. An ANPR + DSRC version may be

mountable in a similar manner, subject to the need for overhead instead of side mounting of the

DSRC tag reader and the width of the highway.

The arrangement in Figure 4 aims to capture front plates as vehicles access the motorway. This

arrangement would not capture motorcycles which do not have front plates.

Figure 4: Illustration of layout for ANPR camera on access ramp

Alternatively a gantry could be located across each access or exit ramp, as used on ETR 407 – see

Figure 1. Overhead camera mounting improves number-plate reading and also makes it simpler to

operate with cameras in both directions reading front and back plates. The mounting points would

need to be chosen carefully.

• On the access ramps which have active traffic management typically narrowing to a single

lane.

• On exit ramps operating with 1, 2 or 3 lanes – overhead mounting would generate a better

read rate than side mounting.

• Where there are separate T2 or T3 lanes giving priority access.

Overhead mounting would also allow heavier equipment, such as vehicle classifiers and triggers, as

used on the Northern Gateway motorway. This is a very robust implementation which we understand

achieves a detection rate of 99%. Each site needs to be engineered to get maximum performance.

Low Speed Environment

Vehicles Accelerating on to Main Carriageway

Camera Field of View

CabinetVehicle Hard

Standing

Access Ramp onto Motorway


The more ‘safety margin’ left in when commissioned, the lower the likelihood of degradation. The

setup of a site needs to be “commissioned” and measured.

In addition to improved ANPR read rates, gantries also can be used to mount tag readers for DSRC

or RFID solutions, and are required for the latter technology. This increases the long-term flexibility of

the gantry infrastructure compared to side-mounted poles.

However these operational advantages for gantries come at the price of increased amenity costs and

higher capital costs. Installation of gantries may be physically difficult due to the space requirements

for the gantries themselves, given limited space on some roadsides and around parts of the

motorways, particularly on/off-ramps. Annex E considers further the performance impacts of using

gantries or cantilevers on entry and exit ramps.

There are also signage requirements which have to be met, which limit how close together gantries

can be placed. The physical size of the gantries, and the fact that they go right over the monitored

lanes mean that the visual impact is significant compared to side-mounted poles.

A local trial should be carried out to get locally relevant performance measures on motorways ramps;

the main question to be addressed is whether the charging policy is distance based – requiring a

detection record for each access and exit to calculate distance. If ANPR cameras only achieve a 98%

read rate for a single pass, there may be only a 96% probability that both access and exit event are

captured automatically. However, where an access event is captured without an exit, or exit captured

without an access image, the relevant plate can be used to search for “partial” or similar plate reads

from the pool of less robust image data using the ANPR “confidence” scale that most products apply.

Main carriageway gantries

Instead of having detection points on access and exit ramps, an alternative option is to have detection

equipment across the main motorway carriageway. Our assumption is that not every section of

motorway between intersections would have a gantry. This would mean the scheme would not be a

“closed” system, but could have the following benefits:

• Significantly fewer detection sites – a high level survey of the motorway suggest there may be

56-68 sections of motorway that require a gantry – compared with ~190 access and exit

points, subject to how the majority of the traffic is captured. Annex C provides an indication of

the sections that could be charged

• Better detection rates: equipment would be mounted directly over lanes eg Northern Gateway

However, using gantries across the whole carriageway has some disadvantages:

• Spanning the whole carriageway in a high speed environment requires more robust gantries

at significantly greater unit cost than for ramps, potentially a multiple of $100k per gantry

• The maintenance of the equipment on the gantries requires engineer access, potentially

through a service road – at greater cost

• The charging system will not be “closed” and drivers may have the option of avoiding some

motorway sections with gantries. This could increase the vehicle traffic on minor roads.


For such a system, modelling would be needed to assess whether at an intersection to intersection

level, drivers would divert to avoid paying a charge.

3.5. Tag and beacon costs and benefits

Tag and beacon, as an addition to ANPR, provides benefits where there is the potential to make

savings through:

• High levels of account take up which increases automated charging. It is usual for tag accounts

to attract a charge discount;

• Reduction in manual checking through a tag transaction not requiring validation. In most cases

both the tag ID and vehicle registration will be captured allowing:

− The link between tag and ID and vehicle to be revalidated or challenged each time the

vehicle is identified;

− If a tag battery fails the infrastructure can diagnose this and trigger a new tag being issued

to the account holder,

• Reduced revenue loss - the performance gap between ANPR and ANPR + DSRC may be of

the order of 1-4% depending on the local implementation.

A number of factors contribute to the cost and benefit assessment, for example:

Table 11: Tag and beacon costs and benefits

Cost Benefit

• The costs of the tags and their management

• The capex for the tag reader infrastructure and its opex maintenance

• The charge discount amount for using a tag account

• Whether the infrastructure can be appropriately sited on the highway concerned – single carriageways

• Savings in manual checking

• Reduced revenue loss through undetected vehicles

• More accurate billing – reduced risk of mis-billing due to ‘false positives’ particularly where multiple detection events contribute to a bill

The original business case for tags arose with toll plazas where replacing a manual toll collector

member of staff with automated raising of the barrier by a tag allowed the scheme operator to make

significant savings. However, for open road charging where there are already ANPR accounts, the

incremental benefits for local schemes of issuing tags are more marginal, as follows:

• If the detection rate improvement for a tag is of the order of say 2%, the additional revenue

may not counter balance the extra costs.

• If there is a saving on manual checking because the tag has confirmed the read – then the

saving needs to apply to a high proportion of users to be worthwhile, and allow the manual

check resource to be significantly reduced.

• If there is an additional discount to the customer for using a tag – this is a cost to the scheme

and may drive an overall net loss.


However, where there are multiple transactions involved in a trip and the differential revenue loss

through poorer detection data from ANPR is of the order of 10% or more, then the case may be

different. Table 12 below illustrates a worked example where there are two scenarios: a 2% and a

break-even scenario using tags, and the consequential impact on daily net revenue. Note this

excludes the cost of the extra roadside beacon infrastructure.

Table 12: Illustration of impact on net revenue per day

Impact on detection data quality Low Break-even

Daily trips 400,000 400,000

Charge level for ANPR ($) 2.00 2.00

Tag-equipped trips (%) 70% 70%

Tag trips per day 280,000 280,000

Tag discount on charge 5% 5%

Difference in trip detection data quality 2% 6.13%

ANPR only trips per day 120,000 120,000

Manual checks avoided per day (@33%) 93,333 93,333

- Staff time (hours@300 checks/hour) 311 311

- Staff time (days) 39 39

Staff FTE cost per day - manual checker ($) 200 200

Manual check staff costs avoided per day $7,778 $7,778

Revenue loss through the discount per day $28,000 $28,000

Additional revenue from better detection per day $11,200 $34,321

Tag cost over life ($) 25.00 25.00

Tags issued 1,400,000 1,400,000

Tag life (years) 7 7

Tag estate cost per day ($) $13,699 $13,699

Tag management cost per day (2 staff) ($) $400 $400

Net gain/loss per day -$23,121 -$0

The 2% and break-even examples for detection data quality improvement are only scenarios:

• Based on the experience at Northern Gateway using just ANPR detection for a single

detection event and achieving 98% read rate, we assume that addition of tags would only

improve detection by 1.5-2%.

• For a more complex charging policy, where multiple reads need to be taken and there was,

say a 5% single passage risk of non-detection or misread, and two passage detection events

were required to be able to charge, then that may equate to a 10% impact scenario.

Where the marginal improvement in detection quality is relatively low, a tag-and-beacon solution

imposes a net cost, with the additional net revenue from improved detection exceeded by the

additional costs of the tags and the assumed discount on tag transactions intended to improve

uptake. The tag-and-beacon break-even scenario above shows that a detection improvement of

approximately 6% is needed to break even under the above assumptions; if an RFID solution is used,

based on a $2 tag costs and all else being equal, then this break-even point is closer to 4%.


Under more complex charging regimes (e.g. a distance-based scheme) the improved detection ability

becomes increasingly beneficial. The actual improvement in trip detection ability required to make tag-

and-beacon-based solutions economic will depend on the read rates achievable by ANPR technology

in practice.

Other approaches are also used to compensate for poorer ANPR read rates or to finance the costs of

tags, for example:

• A video toll manual check charge can be applied.

• Tags may have a monthly fee charge to cover financing costs.

Hence, for the Dartford Crossing Freeflow project – a single site river crossing, not unlike Northern

Gateway - it was decided to be silent in the operator procurement specification on whether tags

should be used, but demand an overall read rate of 98%. This allowed the bidding operators to decide

what technology to adopt to minimise leakage.

The substantial majority of tag and beacon schemes operate on expressways, motorways and tolled

crossings where it is more straightforward to mount the detection equipment.

3.6. Setting detection performance targets

There is often a desire to firmly define the performance capability of a technology and then predict

how it will perform for a specific charging scheme and policy. This can largely be addressed for DSRC

tag detection which has a well-defined technical architecture supported by standards with relatively

few external interfering factors; but for ANPR this is much more complex.

ANPR solutions don’t have the same level of standardisation as DSRC and suppliers prefer to keep

confidential how they work. ANPR performance is affected by the quality of the number plates of the

vehicles that pass, and how clean and visible they are - they can be quite variable. Each site also

needs to be set up to optimise lighting conditions and the field of view through which a number-plate

passes.

The majority of ANPR based road charging schemes achieve their performance through a

combination of factors:

a) Raw image capture quality at the camera head to create a sufficiently good picture that can

also support post-processing in the back office.

b) Character matching and processing speed in real-time (using for example, template matching

or neural networks) as the vehicle passes the camera.

c) Local filtering and automatic correction methods that take into account the available

registration formats, vehicles that are registered as account holders, vehicles that have been

seen before, the preponderance of other text words (such as taxi, long vehicle) that can

sometime look like plates.

d) Being able to grade the quality of the character matching at the camera head with a ranking –

the scales are again proprietary – through a “confidence” measure.


e) Using a secondary ANPR processing engine in the back office that carries out an automated

further review of the plate interpretations.

f) Being able to allocate into separate categories or “buckets”, plate reads that are more or less

likely to have been correct and to which one might apply a different grade of audit sampling.

g) Applying a manual review mechanism according to business rules for each grade of “bucket”

that serves to:

i. Inspect and audit the reads that have been made to retain confidence that the bucket

structure is correct;

ii. Correct reads that turn out to be erroneous when inspected;

iii. Validate that lower categories of bucket are actually “rubbish” that can safely be

discarded.

h) Being able to “catch” incorrect reads later in the process – for example when a reminder or

infringement notice is about to be sent out and it becomes clear that the vehicle details held

with the registrar differ from the image captured.

The overall result of these processes after much fine tuning may achieve a read rate of 94-99% on

average across a wide range of vehicle types, conditions and sites. It is not as simple as assigning a

percentage of correct reads to the camera and then corrections to be delivered by manual checkers.


4. Roadside high level design

In this section we set out a high level design for the roadside technology based on our assumptions

about the quantity and location of the cordon and motorway detection sites required.

4.1. Cordon sites

Table 13 summarises our notes on the sites relating to a possible “inner” cordon with updated lane

numbers and data from a design in 2008. In practice, each site requires a detailed survey to assess

how it would be covered with detection infrastructure. The roadside equipment is assumed to use

ANPR cameras.

Table 13: Proposed Cordon site summary

ID Intersection Lanes (from 08 report)

Updated lanes

Comments following Reviews on 14th & 20th May

1 Northern Motorway – Southbound

8 8 Assumed to be full width of 8 lanes – 2 x 4 lane gantries

2 Tamaki Drive 4 4 Can be done across 4 lanes – 2 pole model. Bridge/causeway may limit foundation size

3 Orakei Road 4 3 3 lanes not 4. Can be done close to roundabout. 2 poles. Bridge may limit foundation/poles

Kelvin Road 2 0 Cul de sac.

Pukeora Avenue Cul de Sac – assumed outside the scheme

4 Ngapuhi Road 2 3 Driveways – 2-3 lanes. Need segregation

5 Luceme Road 2 2 Need segregation. Driveway + rear access to Cartridge World

6 Upland Road 2 3 3 lanes not 2 – parking space, rear access to bar, but could be done with cameras

7 Remuera Road 4 4 Complex location – intersection – rear access for parking at Church, but do-able with 2 poles or gantry

8 Lochiel Road 2 2 Fine. 2 lanes – space for poles

9 Ascot Avenue 2 4 3-4 lanes – space for poles. Segregation needed

10 St Vincents Avenue/Carmont Street

2 2 Telegraph pole obstruction

11 Ohinerau Street 2 2 Extend island to segregate lanes

12 Clonburn Road 4 2 Exit only onto Green Lane East. Maybe only 2 lanes

13 Southern Motorway – 6 8 8 lanes between Greenlane and St Marks (auxiliary lane in each direction)

14 Marewa Road 2 New site to be covered

Retail/Industrial estate parking access/car wash

New access control may be needed

15 Great South Road 4 6 6 lanes not 4. Rear access to McDonalds. Otherwise fine for gantry solution

16 Tawera Road 2 2 Residential drives and access to homes


ID Intersection Lanes (from 08 report)

Updated lanes

Comments following Reviews on 14th & 20th May

17 Wheturangi Road 2 3 3 lanes not 2. Residential drive access

Cornwall Park School Access to school - may need access control

18 Puriri Drive 2 3 Heritage stone wall and narrow access. 2-3 lanes, trees

NZ Exposition Centre + Alexandra Park

Unclear how to manage access and parking

19 Manukau Road 4 5 5 lanes not 4 – pole or gantry access

Alba Road Assumed to be outside the boundary

20 The Drive 4 4 Fine to locate poles/gantries

21 St Andrews Road 4 3 Need segregation – space for poles – may be 3 lanes not 4

22 Penrhyn Road 2 2 Extend island to segregate carriageways

23 Mt Eden Road 4 4 Space for gantry

24 Henley Road 2 2 Residential 2 lanes – no obvious obstructions

25 Westminster Road 2 2 Residential 2 lanes – telegraph pole, driveway

26 Mewburn Avenue 2 2 Residential 2 lanes – no obvious obstructions

Tenderden St Assumed to be cul de sac

Springwood place Assumed to be cul de sac

27 Dominion Road 4 4 Not clear there is enough space before Dunbar Road to mount equipment – also KFC access

28 Eldon Road 2 3 There is enough space before Dunbar Road to mount equipment. Looks like 3 lanes not 2

29 Goring Road 2 2 2 lanes residential. Parking on right, driveways on both sides

30 Sandringham Road 4 5 5 lanes, petrol station, shopping and offices, access to rear

Cornwallis 2 0 Remove to allow access to shopping centre car park

31 Morningside Drive 2 3 Detection Point to go north of Exeter Road to allow access to shopping centre. Width wider than 2 lanes – may be 3

32 Taylors Road 2 2 2 lanes, residential, driveways and rear building access

33 Private road access 2 New road – 2 lanes with access to New North Road

34 New North Road 4 4 May be 5 lanes, residential frontages

Selkirk road access 0 2 lanes access – may be a cul de sac

35 Seychelles Street/Malvern Road

2 2 Seychelles not clearly inter-secting

36 Duncan Maclean Link 2 3 Probably 3 lanes – not 2

37 Auckland Kumeu Motorway - Eastbound

6 6 Assumed to be 6 lanes

38 Great North Road 4 5 May be 5 lanes not 4 – gantry based solution

39 Old Mill Road/Bullock Track

4 4 Maximum 4 lanes

40 Meola Road 2 2 2 lanes residential driveways

40 sites 134


Across the 40 sites, we assume that a set of generic configurations can be applied:

Table 14: Generic configurations for Cordon sites

Configuration Site Drawing ID (Annex B) Number of Sites

8 lane 2 x 4-lane – Sketch 9 2

6 lane 2 x 3-lane – Sketch 8 2

4/5 lane Sketch 6, 2 x Sketch 5 configured to cover 5th lane

13

2/3 lane 2 x Sketch 4 or Sketch 4 + Sketch 5 23

A question was raised as to whether there was a simpler cordon option to that described above. We

therefore reviewed a further option based on only 15 detection sites, but covering a larger area.

Annex D provides an assessment of the technical feasibility such a wider scheme based on a desktop

review of the road network.

4.2. Motorway sites

The motorway network is assumed to stretch from:

• Northern Gateway; to

• Southern Boundary – Southern Motorway end/State Highway start – SH1N

• The North West boundary is the roundabout at Fred Taylor Drive.

Figure 5Figure 5 illustrates the extent of the motorway network assumed to be in scope.

We conducted a high level survey of the motorway access ramps and exits to estimate the required

lane coverage.

Across the estimated 105 on-ramps and 91 off-ramps, we estimate the total 1, 2 and 3-lane ramps are

as set out in Table 15 below. We assume that a set of illustrative site configurations can be applied.

Sketches for the designs are provided at Annex B.

In addition, full motorway width gantries would be required at the three start and end points on the

motorways that continue onwards:

Table 15: Estimate for Motorway configurations

Configuration Drawing ID (Annex B) Number of Sites

On-ramps

2-lane Sketch 2 or 3 3

1- lane Sketch 1 102

Off-ramps

3-lane Sketch 8 1

2-lane Sketch 2 or 3 11

1-lane Sketch 1 79

Motorway End Points

SH1 Northern End 2 x 2 lanes Sketch 8 1

SH1 Southern End, 2 x 2 lanes Sketch 8 1

SH20A Airport, 2 x 2 lanes Sketch 8 1


Figure 5: Motorway Network in scope

Source: Jacobs


Two variations were also considered:

• Vehicle detection only on entry ramps – thereby imposing a motorway access charge

• Detection only on exit ramps – effectively a charge for access to local roads.

On balance, we conclude that of these variations, using entry ramps for detection and charging is

more feasible. Annex F considers these issues in more detail.

4.3. Roadside services

The equipment at the roadside typically requires the following services:

• Power – this is usually a resilient single phase power source and may need to be of a higher

quality than typical street lighting power needs depending on the specific product.

• Data communications – typically over broadband or fibre to the back office and data centre.

This also requires resilience. We assume this would need to be a cabled link as the data

speed required may be of the order of 2M-10Mbps at each site and there may be privacy

restrictions that prevent use of wireless communications.

• A management and diagnostics function which can be integrated with the camera or within a

separate cabinet. If a cabinet is used then it needs to be secured from potential tampering. It

is usual for each site to have a “heart beat” report that regularly reaffirms that it is working

normally and that the data captured is secure and could not have been interfered with.

The equipment needs to meet ingress protection, environmental and electromagnetic compatibility

requirements for the location. Given temperature variability it is advisable to minimise the number of

moving parts.

Where a gantry, pole or cantilever is used a concrete base is needed and the whole structure needs

to be designed in the context of the weight and ‘windage’ of the equipment to be mounted.


5. Maintenance and renewal assumptions

5.1. General maintenance

Typically roadside equipment would be maintained or inspected every 3 or 6 months; it would be

monitored from a central management console to establish its health and allow system alarms and

failures to be captured.

For cameras, the need for evidential integrity of the records captured would require that there was a

regular ‘heart beat’ message logged, indicating the system was working normally.

Contract performance indicators may also require individual measurement and tuning of each site.

Road traffic accidents and street works may cause additional maintenance tasks for the operator and

maintainer.

Signs and highway markings announcing the scheme will also need to be maintained and refreshed.

5.2. Cordon

At this stage we have not scoped the maintenance requirements for roadside equipment. In general

they would follow typical practice for on-street equipment. We have already identified the challenges

for locating detection equipment on the smaller residential roads and also meeting local streetscape

considerations.

5.3. Motorway

We assume the roadside maintenance regime for a motorway option will follow NZ Transport Agency

requirements for operations on the network and safety.

5.4. Refresh cycle

In general asset lives for cameras and roadside beacons are substantially longer than the contracts in

place to operate them. The need to replace or update them may be driven by:

• Hardware or software obsolescence – but in general this aspect of the asset life would be

assessed at the start of the contract.

• Changes in evidential requirements for enforcement.

• Technology evolution over-taking the asset life.


• Changes in the road network or resurfacing, and the opportunity being available to upgrade

the infrastructure while the road is closed.

• The equipment being unserviceable following a traffic accident, and being upgraded with a

new model.

• A new service provider or maintainer being procured with a new service level and KPI regime.

The cameras implemented in London were initially installed on the basis they had a 7 year asset life;

in practice they were replaced with a new integrated camera and ANPR processor version after 5

years – here technology evolution overtook the asset life. In general the asset life of each product is

manufacturer specific. Elements that tend to fail include:

• Power supplies and related batteries and back-up power.

• Disk drives – in general devices at the roadside using disks should be avoided.

5.5. Operational risks

The most significant operational risks to equipment arise from:

• Roadside environmental challenges – heating, cooling, dust and debris blocking vents.

• Poor commissioning for example, sun-blinding caused by the angle of the sun varying

seasonally and preventing an ANPR camera from working.

• Road traffic accidents where the pole or equipment is damaged or emergency services may

cut through power or a cabinet to make the location safe.

• Incidents that arise when equipment is being serviced or maintained or during street or

nearby building works.

• If the site needs to be relocated where carriageway or building works take place.

Items blocking a camera’s field of view and reducing read rate, can include:

• Trees which have additional growth in the spring and need pruning.

• High-sided parked vehicles.

These issues can be addressed during site survey and design.

The signs announcing the scheme can also be damaged by traffic accidents. Road markings

indicating entrances and exits also need to be maintained.


5.6. Highway governance

How the operational highway is governed to enable installation of equipment and maintenance needs

to be determined. The parties involved are assumed to be:

• Auckland Council

• New Zealand Transport Agency in the case of a motorway scheme

• A scheme operator

• A highway maintainer.

These parties will need to agree roles and responsibilities for operation and maintenance and also

who has powers to collect charging revenue, administration charges and fines as this may vary

depending on whether it is on the motorway or on local roads in Auckland. The legislation will need to

set out the governance structure.


6. In-vehicle requirements

The in-vehicle requirements for each option are as follows:

Table 16: In-vehicle requirements for each option

Detection Solution Requirements

ANPR • No in-vehicle requirements

ANPR + DSRC tag and beacon • For account holders a DSRC tag would be fitted inside the front windscreen. The tag could be provided to the user with a deposit and periodic charge

• There is also the potential for video accounts which are charged at a premium to recognise the lower detection rate and manual checking costs

In terms of user compliance costs there are substantial benefits in not requiring in-vehicle equipment

and making the system easy to use. This has also been the approach on Northern Gateway where

the option of using tags has not been taken up to date.


7. Conclusions

Technology choice

The primary technology choice is between:

• ANPR cameras; or

• ANPR cameras + tag and beacon.

At this stage we have not firmly concluded the technology choice because of the risk of poor detection

performance of ANPR systems and potential impact on revenue loss.

However, we have configured a base case of ANPR cameras at the roadside for each of the cordon

and motorway schemes. Depending on the charging policy to be adopted and performance

requirement there may be a need to add tag and beacon to this configuration. This is more feasible to

do for the motorway charging solution given the streetscape issues with a single cordon.

The main advantages of ANPR cameras are:

• Can be used more flexibly to fit with the urban road network

• Less visually intrusive

• Avoids the additional costs of tags and tag readers.

The main advantages of tag and beacon with ANPR over just ANPR are:

• More accurate detection of vehicles with tags fitted

• Reduced manual checking in the back office leading to reduced operating costs

• Still allows casual users without tags to be served.

Performance challenge

With just ANPR, there is a risk that detection performance will be relatively poor - 98% or less per

vehicle passage (vs ~ 99.8% for tags), resulting in:

• Loss of revenue

• Risk that incorrect reads may result in charges being applied to the wrong account – this can

be reduced through additional manual checking

For reference, Stockholm claims a vehicle detection rate of 98% and Northern Gateway 97-99%; both

schemes use ANPR cameras but are also mounted on overhead gantries to improve detection rates.


Before any performance expectation is set for the cordon, there should be a trial to test vehicle

capture rates.

Similarly, implementing a camera site on a motorway access and exit ramp would provide lessons on

performance and collaboration between the agencies involved at the roadside.

Scheme complexity

In comparison with other schemes the options proposed are relatively complex:

• The cordon scheme has ~40 detection locations – more than double the size of Stockholm and

also in largely residential areas with some significant spatial and aesthetic constraints.

• The motorway scheme has ~190 access and exit ramps – this is a substantial implementation

project. It may be advisable to consider breaking it up into discrete stages.

Alternatively, the analysis at Annex C for a “mainline” gantry-based approach for the motorways –

instead of access and exit ramps - suggests that between 56 and 68 full gantries may be required.

This would still be a substantial project but could also be staged by motorway.

Motorway Scheme

On balance we conclude that based on technology considerations, charging on the motorway is more

feasible than for a cordon scheme.

We have also explored the infrastructure required for charging based on:

A. Entry and exit detection, which would enable a distance based approach but also require the

most infrastructure.

B. Entry detection only – effectively an access charge, which we understand is the preferred

option from a policy point of view.

C. Exit detection only – effectively a charge for motorway users who seek access onto the local

roads, though we have only considered this at a high level.

D. A “mainline” gantry based approach with charging for each section of motorway.

We conclude that options A, B and D are technically feasible. Option C would require further analysis.


Annex A – Scope of Deliverable B.1 Technology

Scope of Deliverable B.1 Technology

An analysis of the range of available vehicle detection and identification technologies, and

recommendations for a preferred technology for a single cordon or motorway road pricing scheme in

Auckland.

Identification of the roadside infrastructure, the associated maintenance and renewal requirements,

and the in-vehicle requirements needed to support the detection and identification technology.


Annex B – Illustrative designs for the roadside technology

Illustrative designs for the roadside technology

Illustrative designs for roadside equipment and camera mountings

• Sketch 1 – Single Lane, Single Camera On-Ramp

• Sketch 2 – Two Lane Access, Dual Camera (Pole)

• Sketch 3 - Two Lane Access, Dual Camera (Gantry)

• Sketch 4 – Residential/Local Road, Single Lane, Pole

• Sketch 5 – Residential/Local Road, Cantilever Pole – 2 x 2 Lanes

• Sketch 6 – Residential/Local Road, 4-Lane Gantry

• Sketch 7 – Residential/Local Road, 2-lane Gantry

• Sketch 8 – Motorway, 3-Lane Gantry

• Sketch 9 – Motorway, 4-Lane Gantry

Assumptions – On-motorway ramps

• Height of 6m

• Gantries will have a clearance of 6 metres

• Over-lane engineer working will require access to the gantry, including hard standing area and

safe vehicle entry/egress

• For ramps which allow vehicle access, one by one, to the motorway under ramp metering, the

detection point will be at the point of the single vehicle lane

• Where possible roadside equipment/cabinets will be placed on local roads to ease engineer

access

• Ramp closures will be required to enable maintenance of equipment to be managed in line with

a protocol to be agreed with NZTA [Note: Maintenance on Northern Gateway takes place every

3 months]

• Frangible poles will be used

• Off ramps will have similar assumptions


Figure 6: Sketch 1 – single lane, single camera on-ramp


Figure 7: Sketch 2 – two lane access, dual camera (pole)


Figure 8: Sketch 3 - two lane access, dual camera (gantry)


Figure 9: Sketch 4 residential/ local road, single lane, pole height 6m


Figure 10: Sketch 5 residential/ local road, cantilever pole - 2 x 2 lanes


Figure 11: Sketch 6 residential/ local road, 4-lane gantry


Figure 12: Sketch 7 residential/ local road, 2-lane gantry; Sketch 8 – motorway, 3-lane gantry; Sketch 9 – motorway, 4-lane gantry


Annex C – Motorway charging scheme – main highway gantries

The following mainline sections of motorway are candidates for having a tolling gantry. In some cases

we may decide a gantry is not needed on that section – identified as a “Not Toll Option”.

SH1

Table 17: SH1 - Main highway gantries

Section From To Not Toll Option?

1 Grand drive Wainui Road

2 Wainui Road Exit 398 Silverdale Yes

3 Exit 398 Exit 410 Oteha Valley Road

4 Exit 410 Exit 412 Greville Rd

5 Exit 412 Exit 414 Upper Harbour & SH18

6 Exit 414 Exit 417 Tristram Avenue

7 Exit 417 Exit 419 Northcote Road

8 Exit 419 Exit 420 Esmonde Rd

9 Exit 420 Exit 421 Onewa Rd

10 Exit 421 Exit 422 Stafford Road

11 Exit 422 Exit 423 Shelly Beach Road

12 Exit 423 Shelly Beach Road Exit 424 Fanshawe St

13 Exit 424 Fanshawe St Exit 425 Cook Street

14 Exit 425 Cook Street Exit 427 Nelson St

15 Exit 427 Nelson St Exit 4-AbC

16 Exit 4-AbC Exit 427 Waitakere Helensville

17 Exit 427 Waitakere Helensville Exit 430 Kyber Pass

18 Exit 430 Kyber Pass Exit 431 Gillies

19 Exit 431 Gillies Marks St

20 Marks St Exit 432 Market Rd

21 Exit 432 Market Rd Exit 433 Green Lane East

22 Exit 433 Green Lane East Tecoma

23 Tecoma Exit 435 Ellerslie Panmuire Yes

24 Exit 435 Ellerslie Panmure Exit 437 South Eastern Highway Yes

25 Exit 437 South Eastern Highway Exit 438 Mt Wellington Highway

26 Exit 438 Mt Wellington Highway Exit 441 Princes St

27 Exit 441 Princes St Exit 443 Highbrook Drive

28 Exit 443 Highbrook Drive Exit 444 East Tamaki Rd

29 Exit 444 East Tamaki Rd Exit 447 Te Irirangi Dr

30 Exit 447 Te Irirangi Dr Exit 448 Manakau Yes

31 Exit 448 Manakau Exit 449 Great South Road Yes

32 Exit 449 Great South Road Exit 451 Hill Road

33 Exit 451 Hill Road Exit 453 Takanini

34 Exit 453 Takanini Exit 458 Papakura

35 Exit 458 Papakura Exit 461 Drury

36 Exit 461 Drury Exit 466 Ramarana


SH16


Section From To Not Toll Option? 1 Fred Taylor Drive Exit 11/10 2 Exit 11/10 Exit 18 Royal Road Makora Park 3 Exit 18 Royal Road Makora Park Exit 16 Lincoln Road 4 Exit 16 Lincoln Road Exit 14 Te Atatu Rd 5 Exit 14 Te Atatu Rd Exit 12 Patiki Road 6 Exit 12 Patiki Road Exit 11 Rosebank Rd Yes 7 Exit 11 Rosebank Rd Exit 8 Great North Road 8 Exit 8 Great North Road Exit 6 St Lukes Road 9 Exit 6 St Lukes Road Exit 5 Newton Rd 10 Exit 5 Newton Rd Exit 4 ABC Yes

SH18



1 Exit 414 Exit 2 Yes

2 Exit 2 Exit 4

3 Exit 4 Exit 6

4 Exit 6 Exit 8

5 Exit 8 Exit 9

6 Exit 9 Exit 10

7 Exit 10 Exit 11 Yes

SH20



1 Exit 8 H16 Stoddard Rd

2 Stoddard Rd Exit 18 Dominion Rd

3 Exit 18 Dominion Rd Exit 16 Hilsborough Road

4 Exit 16 Hilsborough Road Exit 15 Queenstown Rd

5 Exit 15 Queenstown Rd Exit 13 Neilson Street

6 Exit 13 Neilson Street Exit 12 Mahunga Dr

7 Exit 12 Mahunga Dr Exit 10 Walmsley Rd

8 Exit 10 Walmsley Rd Exit 9 Airport

9 Exit 9 Airport Exit 7 Massey Road

10 Exit 7 Massey Road Exit 3 Cavendish Drive/Puhinui Rd

11 Exit 3 Cavendish Drive/Puhinui Rd Exit 1 SH1

SH20A

Table 21: SH20A - Main highway gantries


1 Exit 9 Kirkbride/Massey

2 Kirkbride/Massey Montgomerie Road Yes

3 Montgomerie Road Landing Drive Yes

4 Landing Drive Nixon Rd Yes


Summary

Table 22: Summary - Main highway gantries

Road Sections Optional

SH1 36 5

SH16 10 2

SH18 7 2

SH20 11 0

SH20A 4 3

Total 68 12

On this basis, we estimate that between 56 and 68 full gantries would be required for this option.

On the assumption that each gantry will on average cover 6 lanes, (3 in each direction), we would

require 336-408 lanes to be monitored. If we use 2 cameras per lane – front and rear plate capture –

that would require 672-816 cameras.

The precise number of lanes and cameras would be subject to a full survey.


Annex D – Illustration of a Wider Cordon Scheme

Figure 13 illustrates a potential wider cordon scheme boundary based on the isthmus, with the aim of

reducing the number of detection sites while still potentially meeting the scheme objectives.

Figure 13: Illustration of a Wider Cordon


This scheme is estimated to require only 15 detection points. The choice of boundary on the western

side is most challenging. For example, if we follow a line east of Portage Road, the detection points

would be on:

• Ash Street east of the Wairu junction

• Great North Road west of the junction with Portage Road

• Clark Street just west of the Ulster street junction

• Bolton Street west of the Castlewood junction

• Kinross Street east of the roundabout serving Portage Road

• Connaught Street just east of the junction with Godley Road.

The Ash Street and Bolton Street detection points would need careful planning to fit with drives,

shops, parking and nearby houses. The other sites on the boundary are more straightforward. A full

site survey would be required to confirm feasibility, though the table below provides initial comments

from a desktop review.

No Detection Point Location Lanes Issues & Comments Relative Feasibility

1 Harbour Bridge 3 + 4 • Movement of the lane divider. Bridge mounting

Yes

2 SH16 3+3 • Dual carriageway on a bridge Yes

3 Ash Street east of the Wairu junction

4 • Drives of houses on North side of Ash Street may make aesthetics difficult.

• Room for a gantry

Maybe

4 Great North Road west of the junction with Portage Road

2 • On the bridge (Whau River) may be a suitable location for a gantry

Yes

5 Wolverton Street just west of the Ulster street junction

3 • Clear section for a gantry just east of the Gull petrol station

Yes

6 Bolton Street west of the Castlewood junction

2 • Parking and shops on south side of Bolton Street, Houses & drives on North side

Maybe

7 Kinross Street east of the roundabout serving Portage Road

2 • Clear country road. • Room for gantry

Yes

8 Connaught Street just east of the junction with Godley Road

2 • Clear wooded road. • Room for a gantry

Yes

9 Mangere Bridge 4+4+1 • Bus lane on Southbound. • Room for gantry

Yes

10 Great South Road North of the junction with Portage Road

4 • Clear wide road with space for a gantry

Yes

11 Abattoir Lane where it meets the Great South Road

1.5 • Narrow lane with space for light gantry

Yes

12 Mt Wellington Highway south of the New Brighton junction

2 • Two properties either side with driveways but room for a light gantry.

• Aesthetics may need some

Yes


No Detection Point Location Lanes Issues & Comments Relative Feasibility

attention

13 SH1 north of Exit 441 Princes St

3+3 • Dual carriageway on a bridge Yes

14 South Eastern Highway/ Pakuranga Highway on Waipuna Bridge

2+2 • Dual carriageway on a bridge Yes

15 Lagoon Drive on Panmure Bridge

3 • Aesthetics may need attention - but room for a gantry

Yes

How Does This Compare with the Primary Cordon Option from a Technical Perspective?

Advantages Disadvantages

• Less sites to install reduces project management complexity

• More space at a site permits more effective detection infrastructure – overhead gantries + cameras in both directions over each lane

• Detection rate per passage should be greater on average

• Stakeholders should be less likely to object on aesthetic grounds

• Overall infrastructure capex may be slightly lower.

• Unit site cost will be higher on average

The comparison above does not consider differences in:

• The nearby institutions affected: schools, hospitals, golf courses etc

• Whether stakeholders might object to being close to the boundary

• The traffic volumes across the cordon and therefore revenue raised

• Impacts on driver journeys or congestion

• Communities which are split by the boundary.


Annex E – Gantries vs Side-Mounted Poles and Cameras

The two primary means of mounting detection equipment is on either gantries or side-mounted poles.

There are costs and benefits associated with both of these approaches. The key differences are

summarised in Table 23 below:

Table 23: Comparison of Gantries and Side-mounted Poles

Gantries Side-mounted Poles

Pros

• Better read rates (say 96-98%)

• Able to install cameras facing both ways (so can capture front & back plates)

• Once installed, provide ability to later upgrade to usage of distance based charging or OBUs

• Allows heavier equipment, such as vehicle classifiers and triggers

• Required for RFID technology solution

Pros

• Lower cost

• Lower visual impact

• Easier to fit into urban environment, requiring less space to mount

Cons

• Installation may be physically difficult

• Less likely to match local streetscape, leading to acceptance issues

• Higher capital costs

Cons

• High sided vehicles obscure detection

• Skewed viewing point reduces read quality

• Risk of Lower read rates (say 92-95%)

• Less effective in capturing motorcycle rear plates

Gantry infrastructure is more difficult to fit into local streetscapes and requires additional space to

physically mount, as well as being more expensive to build and maintain. However it is also enhances

detection rates (including motorcycles) and enables improved technical capabilities and greater

flexibility, including the ability to move to OBU-based technology.

Installation of gantries may be physically difficult due to the space requirements for the gantries

themselves, given limited space on some roadsides and around parts of the motorways, particularly

on/off-ramps. There are also signage requirements which have to be met, which limit how close

together gantries can be placed. The physical size of the gantries, and the fact that they go right over

the monitored lanes mean that the visual impact is significant compared to side-mounted poles. This

will be a greater concern for the Cordon charging scheme than the Motorway charging scheme. The

vast majority of open road motorway charging schemes use gantries for equipment mounting.


Overhead camera mounting improves number-plate reading and also makes it simpler to operate with

cameras in both directions reading front and back plates, thereby improving read rates, although the

mounting points need to be chosen carefully. The use of cameras facing both ways enables capture

of both trucks (whose rear plates can be dirty or obscured) so front plate capture is preferred, and

motorcycles (which lack front plates). Gantries therefore provide a better mounting solution in terms of

read rates. Many factors such as road layout, opportunities for obscuration, lighting, plate quality and

back office manual checking approach affect the plates read. Read rate may be of the order of 96-

98% read rate if the cameras are mounted overhead; or 90-96% if the cameras are mounted at the

side of the road.

In addition to improved ANPR read rates, gantries also can be used to mount tag readers for DSRC

or RFID solutions, and are required for the latter technology. This increases the long-term flexibility of

the gantry infrastructure compared to side-mounted poles.

However these operational advantages for gantries come at the price of increased amenity costs and

higher capital costs.

Some of these costs can be mitigated if instead of having detection points on access and exit ramps,

detection equipment is placed across the main motorway carriageway. If not every section of

motorway between intersections has a gantry, it would mean the scheme would not be a “closed”

system, but could have the following benefits:

1. Significantly fewer detection sites – a high level survey of the motorway suggest there may be

56-68 sections of motorway that require a gantry – compared with ~190 access and exit

points, subject to how the majority of the traffic is captured.

2. Better detection rates as equipment would be mounted directly over a lane – as for Northern

Gateway.

However, using gantries across the whole carriageway also has some disadvantages:

1. Spanning the whole carriageway in a high speed environment requires more robust gantries

at significantly greater unit cost than for ramps, potentially a multiple of $100k per gantry.

2. The maintenance of the equipment on the gantries requires engineer access, potentially

through a service road – at greater cost.

3. The charging system may not be “closed” if not all motorway sections have a charging gantry;

drivers may therefore have the option of avoiding some motorway sections with gantries. This

could increase the vehicle traffic on minor roads as drivers divert. Note the estimated 56-68

sites would involve gantries on every section

4. For an “instance” based charging scheme there would need to be some protocols agreed at

the back office such that vehicles passing under multiple gantries on the motorway are not

charged multiple times for a single trip on the motorway. This is easier to manage when only

access points are charged.

The decision whether to use gantries rather than side-mounted poles depends on whether the

improved read rates of the gantry-based infrastructure exceeds the greater capital and amenity costs.


The capital cost savings of side-mounted poles could be smaller than the revenue lost from leakage

due to lower read accuracy. We provide the following illustrative example based on a set of

assumptions:

• If capital savings of side mounting on access and exit ramps are in the order of say $1-12

million depending on the type of scheme (access charge or distance-based) being considered;

• Assuming 400,000 trips per day at a charge of $2 per trip, with charges levied 365 days p.a.,

revenue generated would be $292 million p.a.

Table 24 below summarises an illustration of the potential impact of revenue leakage on net annual

revenue:

Table 24: Illustration of Revenue Leakage

Read rate Annual Net Revenue ($000) Revenue Leakage ($000)

92% $268,640 $23,360

93% $271,560 $20,440

94% $274,480 $17,520

95% $277,400 $14,600

96% $280,320 $11,680

97% $283,240 $8,760

98% $286,160 $5,840

99% $289,080 $2,920

100% $292,000

As shown in Table 24 above:

• If the read rate was 92% (with side mounted cameras) but increased to 98% (gantries) then at

the extreme end, the revenue impact could be as much as $17.5m p.a.

• If the read rate was closer to 95% (100% side mounted) but increased to only 96% (gantries)

than a more modest revenue impact could be expected in the order of around $3m p.a.

• In reality it is likely to be somewhere between these two, say a 2-3% improvement which would

generate a revenue improvement in the order of $6m - $9m p.a.

At these levels of improvement, there would appear to be adequate justification for the additional

infrastructure cost, noting also that gantries enable effective charging of motorcycles. The key

downside is visual amenity, which on a motorway may not be a significant issue.

Where read rate is lower, additional back office processing is required to extract the good reads from

the poor quality data. This has an additional cost.


As an example, Toronto Electronic Toll Road (ETR) 407 in Canada:

• Uses gantries on access and exit ramps and applies a distance-based and time based charge.

Figure 14 illustrates a single lane access with gantries.

• Allows users to have an OBU or pay through camera based detection.

• It also uses full span gantries to provide a charge zoning function and secondary opportunity to

read vehicle plates or validate traffic already captured.

• Camera read rate is not published but is likely to be of the order of 98-99% per vehicle

passage.

It applies two types of charge for video detection:

• A distance based charge depending on the entry and exit points – requiring captures at each

point

• A flat rate access charge if the systems have only detected an access or exit event but cannot

calculate a distance charge.

Figure 14: ETR407 – Dundas Street Access

Source: Google StreetView

A recent presentation on ETR 407 indicated that through a set of refinements “unbillable” trips

reduced from 3.8% to 2.4% over 2007-2013 through detection technology refinements.

This type of tailoring of detection rates and charge structure can also be applied to an Auckland

Motorway scheme to refine the overall revenue.


Annex F – Entry or Exit Charging on Motorways

Feasibility of a Charge on Exit

An option being considered for motorway charging is whether to:

• Charge on entry to the motorway system – an access charge. This is the base proposal for a

charging scheme and would seem logical given that the motorways are the most congested

routes during peak hours; or

• Apply a charge on exit – effectively a charge for accessing local roads.

We have not modelled the impacts of charging on exit, but following a high level review, we consider

a charge on entry is likely to be more practical for the following reasons:

• Driver understanding and resulting behaviour

• Potential traffic impacts on the motorway of an exit charge

• Impact on motorway junctions just outside the charged area

• Infrastructure scale and costs.

We examine each of these points below. An option based on charging at motorway exits would need

each of these points to be assessed in further detail.

Driver understanding

Drivers will need to be aware of the cost they incur as they decide to exit, so will need signs warning

them of this well before they exit – additional signage costs. If any form of time based pricing is used,

the signs will need to be variable – for example a charge structure with four time bands charged at $3,

$2, $1 and $0 would need to be thought through carefully. There would be extra capital expenditure

and operating costs on the variable displays and their management.

The applicable charge for a timed exit events may be affected if vehicles are delayed in exiting the

motorway; we may need to operate a “shoulder period” at charge thresholds where vehicles subject to

a higher charge level are actually charged a lower amount to make up for traffic delays preventing

them from exiting at the time “they had intended”. Say for example at busy time, it takes 3-5 minutes

to queue at an exit ramp, to get of the motorway, then the shoulder period may need to be that

long. If accidents or diversions on the local road network delay exit from the motorway then similar

issues will apply and driver may want to be charged the lesser amount. This could all generate large

volumes of customer queries and correspondence, particularly if we have itemised bills with each exit

event and timestamp recorded, which the customer can subsequently challenge.


Potential Traffic Impacts on the Motorway

As drivers will be more aware of the cost of exiting, close to a price transition point, they may be

tempted to:

• Delay their exit awaiting the cost going down and continue on the motorway to a later junction.

• Drive off the motorway faster as they anticipate the cost increasing – maybe accelerating

towards the detection point to beat the price rise – with potential safety impacts.

This may generate more disruptive motorway traffic flow as drivers slow down, speed up and change

their minds, and should be modelled with a real-time traffic flow tool (like Transyt or Vissim). Such

disruptive vehicle flow may increase emissions from vehicles.

Strategically, the main congestion is currently on the motorways during peak hours. It is not clear

what the benefits and impacts of an exit charge would be.

Impact on motorway junctions just outside the charged area

There is a risk that vehicles may avoid the final charged exit and continue on to the next intersection

just outside the charged area to avoid the exit charge, and then turn back towards their intended

destination, increasing traffic at these first uncharged junctions.

Technology Infrastructure

Regarding the technology there are some additional infrastructure impacts.

At exits, we don’t have the benefit of the ramp metering at entry points, so vehicles may be moving

faster and there may be more instances of multiple lanes at exit ramps.

We may need more cameras and wider ramp gantry structures at exit locations where there are 2 or

more exit lanes:

1. a vehicle may straddle the lanes as it exits so processing may need to consider input from

multiple cameras

2. we may have overlapping camera fields of view, or require cameras to have a wider field of

view (7-8m instead of 3.5-4m) – less products and therefore less supply competition

Depending on the layout of each ramp we may not always be able to locate front plate reading

cameras – we may need to add some rear facing cameras also

This means the design will be more dependent on a survey.

auckland council road charging options study: scheme...

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