1

Evidence in support of my Submission Regarding the Pūhoi

to Wellsford Road of National Significance Notice of

Requirement

Contents

Contents .................................................................................................................................................. 1

1 Operational Noise —Proposed Consent Condition ........................................................................ 2

2 Operational Noise—the relationship between the AEE and mitigation; and why it is important

that the AEE identify all adverse noise effects ....................................................................................... 2

2.1. Incomplete Assessment of Adverse Environmental Effects ................................................... 2

2.2. The RMA and BPO ................................................................................................................... 4

2.3. Aggregating Properties ........................................................................................................... 4

2.4. Mitigation Options Where Noise is Considered Reasonable (ie BPO does not apply) ........... 5

2.5. Reasonable Noise .................................................................................................................... 6

3 Kaipara Flats Road / SH1 Intersection ............................................................................................. 7

3.1. AEE and EIC Statements re this Intersection .......................................................................... 7

3.2. Description of Model .............................................................................................................. 9

3.3. Additional Information .......................................................................................................... 10

3.4. Base Model ........................................................................................................................... 10

3.5. Sensitivity Analyses ............................................................................................................... 12

3.6. Appendix 1 - Additional Data from NZTA - Kaipara Flats / Sh1 Intersection Traffic flows .... 14

3.7. Appendix 2 - Additional Data from NZTA - Roundabout Traffic flows .................................. 14

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1 Operational Noise —Proposed Consent Condition

The Proposed Consent condition number 72 requires "The Requiring Authority shall implement

low-noise road surfaces no later than twelve (12) months following completion of construction of

the Project."

If there is an engineering reason for the potential twelve month delay it should be documented and

hence able to be tested by the Board of Inquiry Process. Otherwise, the proposed condition should

be modified to require the agreed low noise road surface be in place prior to the project opening for

traffic.

2 Operational Noise—the relationship between the AEE and

mitigation; and why it is important that the AEE identify all adverse

noise effects

The following expands upon matters discussed in my Submission and specifically documents a link

between assessment and mitigation that is only hinted at in my Submission.

2.1. Incomplete Assessment of Adverse Environmental Effects

The AEE only covers some situations where there are adverse noise effects—namely PPFs (generally

residences) within 200 meters that are built on (i.e. "occupied"). There are other situations that are

not covered—

properties within 200m that are not built on

properties beyond 200m whether built on or not

those parts of properties within 200m that are not built on

This is problematic for the following reasons—

1. Many residents are unable to determine the likely noise impact of the proposed motorway

2. The RMA requires a full assessment of effects. The RMA has two potentially conflicting

paragraphs—

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Schedule 4 S1(d) "Matters that should be included in an assessment of effects on the

environment" requires "an assessment of the actual or potential effect on the

environment of the proposed activity", whereas

Schedule 4 S2 "Matters that should be considered when preparing an assessment of

effects on the environment" requires "any discharge of contaminants into the

environment, including any unreasonable emission of noise and options for the

treatment and disposal of contaminants:"

In my view there is a clear requirement in Schedule 4 S1(d) to include all adverse effects

(including noise and without limiting it to only unreasonable noise) and that requirement is

not extinguished by S2 which refers to consideration rather than inclusion.

3. The AEE provides no input on what is considered unreasonable or why. It relies upon the

Standard (NZS 6806:2010) which I discuss in my Submission should not be the controlling

document. See also the discussion below on Reasonable Noise.

4. There is an argument that undeveloped properties cannot have specific site focused

mitigation as there is no residence to focus upon. This is not true in modern subdivisions

where sites are generally identified at the time of subdivision. Such situations should be

specifically allowed for in NZTA's mitigation analysis.

5. No consideration is given to outdoor living considerations which in rural areas frequently

apply well beyond the location of the residence.

6. Government policy per the Cabinet paper "2013 Resource Management Reforms: Public

Works Act 1981: Amendments" 1 regarding proposed changes to the Public Works Act

approves work to proceed on a bill that would include a Solatium payment for undeveloped

properties that are acquired. This recognises that undeveloped land has a value to its owner

beyond its market value. Although this will apply only to land that is taken its reasonable to

assume that other nearby land (which could have been taken had a different alignment been

chosen) should similarly qualify under this proposal. Further, although this is not currently

1 http://www.linz.govt.nz/sites/default/files/docs/crownproperty/cab-min-2013.pdf

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legislated for some weight should be placed upon it as it is approved by Cabinet for inclusion

in the legislative process.

Therefore undeveloped land should be considered.

7. The aggregate impact of considering currently excluded properties means that an overall

better solution to noise should be possible. This is discussed further below.

2.2. The RMA and BPO

The RMA (s16) places a duty on occupiers to use " the best practicable option to ensure that the

emission of noise from that land or water does not exceed a reasonable level". This addresses noise

emissions that exceed the threshold of "reasonable" but is silent about adverse noise effects that

are below that threshold. There remains a requirement to make an attempt to mitigate those effects

but without being constrained by undertaking the Best Practicable Option.

2.3. Aggregating Properties

The impact of mitigating (partially or fully) distant properties or unoccupied nearby properties may

well provide some benefits to other nearby properties. And by implication, aggregating the

mitigation work into one "package" would in some situations allow for a greater level of mitigation

for all concerned. (There is an Appendix to the Standard that takes a similar approach but only

considers properties with > 57dB. Extending it to all properties with adverse effects should

significantly reduce the adverse noise effects across a wide area of land.)

Therefore a better overall result should be obtained if properties below the reasonable threshold

are included in the analysis of mitigation.

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2.4. Mitigation Options Where Noise is Considered Reasonable (ie BPO does not

apply)

Road Surface Mitigation

There is a possible argument that using a low noise road surface and no other form of mitigation

meets the mitigation requirements for these residences. If this is the case (which I do not agree

with) there should be an analysis within the AEE of the impact of including low noise surface in areas

where it is not currently proposed. (This analysis should be provided anyway.)

If a low noise road surface is proposed to mitigate properties with unreasonable noise levels, then

this alone should not completely satisfy the obligation to consider mitigation of other properties

with lesser noise levels. Rather the low noise road surface should be considered as a part of such

mitigation.

Therefore road surface mitigation alone does not meet the requirements of the RMA unless it is

demonstrated that other measures to reduce noise levels necessitate following BPO. i.e. Some

additional analysis is required before dismissing barriers, bunds etc.

Other (Focused) Forms of Mitigation

Forms of mitigation such as barriers and bunds should be considered for all properties once the

impact of low noise road surfacing (where proposed) is allowed for. Because there is not a need to

meet BPO in situations where the noise levels are deemed Reasonable, the arguments in the AEE

and Operational Noise Assessment Report about heights, visual impacts and costs of walls and bunds

should be largely discounted.

A clear example where additional barriers may be of benefit is the Carran Road viaduct. In this case

its likely because of the shape of the valley that significant amounts of noise will propagate both east

and west (the latter into particularly quiet areas). An analysis of raising the barrier height of that

viaduct beyond what is required for safety reasons should show significant benefit to quite a number

of properties.

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2.5. Reasonable Noise

The approach being taken by NZTA follows the Standard (which I separately argue in my Submission

should not be the ruling document) in drawing a line at 57dB. Those under this noise level receive no

mitigation and those over are considered under the BPO sections of the RMA.

As well as there being no clear justification for using 57B, this creates a nonsense in the hypothetical

case where—

Property 1 Before project 56 db

With project 57 db (i.e. no noticeable sound difference as < 3dB)

Mitigation considered because overall level considered not Reasonable

Property 2 Before project 46 db

With project 56 db (i.e. doubling of sound level)

Mitigation not considered because overall level considered Reasonable

Surely a doubling of sound levels deserves consideration for mitigation whereas an indiscernible

increase of 1 dB does not. This is out of line with the RMA requirement (s2(a)) to consider the

sensitivity of the receiving environment, and is it wrong from a common sense perspective.

Whilst I do not expect this exact situation to occur in this project there will be situations where those

with smaller increases in noise are treated better than those with larger increases in noise. This

scenario shows that the Standard has not been well considered—despite being produced by experts.

This is presumably because it has not been adequately considered against real world situations.

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3 Kaipara Flats Road / SH1 Intersection

In order to gain an understanding of the existing Kaipara Flats intersection and how it would perform

with the motorway in operation, I wrote a program to model traffic flows. (I programmed this as I do

not have access to appropriate simulation software). I recognise that my model has some

approximations but nevertheless I believe that (subject to using the correct parameters) it provides a

reasonable view of the intersection.

Summaries of various scenarios are shown below. The clear result using the 2026 traffic predictions

from NZTA is that the Kaipara Flats Road / SH1 intersection is at best marginal and depending on

assumptions made will at times be unable to cope with peak hour traffic flows.

One scenario of particular concern is the 9% growth forecast which equates to 2 years at 4.4%

compound annual growth. This shows a very substantial deterioration in performance of the

intersection and indicates that using the 2026 traffic predictions may be quite inappropriate should

the opening of the motorway be delayed.

3.1. AEE and EIC Statements re this Intersection

It appears that NZTA's thinking re this intersection has advanced. Whereas the AEE solely addresses

traffic turning from SH1 southbound into Kaipara Flats Road2 the EIC also makes allowance for a

southbound acceleration lane3. The latter issue is the most critical aspect of this intersection. The

generalised nature of the wording in the EIC makes it unclear quite what NZTA proposes (although I

do understand that NZTA needs some design flexibility). Does it mean that—

1. SH1 southbound traffic will have a safe (and fully separated) holding lane in the centre of

SH1 to use whilst waiting for a gap in north bound traffic before turning into Kaipara Flats

Road, and

2. Kaipara Flats Road traffic turning south into SH1 will have a safe (and fully separated)

holding lane in the centre of SH1 to accelerate to 100kph (or whatever the expected target

2Operational Traffic Assessment Report p 56—"The Project design has allowed for the upgrade of the Kaipara Flats Road

intersection immediately north of the proposed Project tie-in with SH1 with the provision of a right turn bay." 3Statement of evidence of Andrew Bell (transportation and traffic) for the New Zealand Transport Agency para 55 "In my

assessment I recommended changes to the Kaipara Flats Intersection including a right turn bay on SH1 in the southbound direction and a southbound acceleration lane."

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speed will be at the point of merging) before needing to merge with other SH1 southbound

traffic?

If these are what is meant within the EIC titled "Statement of evidence of Andrew Bell

(transportation and traffic) for the New Zealand Transport Agency" and in proposed designation

condition 74 then much of my concern about this intersection is addressed. But this leaves unclear

several matters—

the appropriate year to use for traffic modelling given the unknown completion date of the

project,

the intersection capacity especially with regard ex Kaipara Flats Road traffic (as the proposed

condition only addresses safety),

an understanding of what a "Stage 3 Safety Audit" comprises, and

whether there will be any public scrutiny of the proposal (as there is of the overall project).

Based on present information, I believe that the proposed consent condition number 74 should be

amended to —

require the proposed upgrade to be based on the predicted traffic model ten years after

opening of the motorway to traffic,

require the proposed upgrade have sufficient capacity to allow traffic from Kaipara Flats

Road to continue to flow safely with minimal delays (as written it currently only requires

safety), and

require a reasonable level of public scrutiny to the final solution

And that NZTA provide a definition of what a Stage 3 Safety Audit comprises.

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3.2. Description of Model

The basics of the program are—

1. All modelling is done in seconds and simulations in tenths of a second. This includes

determining delays between traffic passing key points such as Top-Of-The-Dome to Kaipara

Flats Road and Kaipara Flats Road to Roundabout

2. Inbound traffic patterns are generated randomly, but adjusted to allow for safe following

distances.

3. South bound traffic is bunched behind slow traffic from the Top-Of-The-Dome. Bunching is

controlled by parameters.

4. North bound traffic at Kaipara Flats Road all comes from the proposed roundabout

5. The proposed roundabout has 2 lane entrances, 2 lane exits and 2 lanes going around. This

is per the published drawing R-115

6. Traffic from the new motorway is assumed to arrive randomly at the roundabout (subject to

an adjustment for safe following distances)

7. Traffic from Warkworth is assumed to arrive at the roundabout in bursts reflecting the lights

cycle at Hill St. The cycle length is 100 seconds and sufficient time is allowed to enable north

bound traffic to not significantly back up

8. The impact of the new Hudson Rd lights is assumed to have no additional effect on traffic

bunching so is ignored. (This is an approximation)

9. The roundabout follows standard conventions re Give Way signs.

10. All southbound traffic from Kaipara Flats Road goes on to the roundabout

11. Various parameters allow changes to traffic spacing assumptions including—

Safe gap between vehicles

Safe gap before turning from Kaipara Flats Road to SH1 southbound

Safe Gap before entering the Roundabout

12. Various parameters allow traffic levels to be set at the following points—

Southbound - split between destination Warkworth and Motorway

Northbound from Motorway - split between destinations SH1 north and Warkworth

Northbound from Warkworth - split between destinations Motorway (southbound) and

SH1 northbound

13. Ability to adjust overall traffic volumes by a percentage (to roughly simulate earlier or later

years)

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14. The model was run 100 times under each scenario in order to get a feel of the impact of

randomness.

15. The key outputs are—

the number of gaps available to traffic turning from Kaipara Flats Road and

the number of vehicles that those gaps could accommodate (allowing for a percentage of

gaps sufficient for multiple vehicles)

16. The model does not model average wait times for traffic waiting on Kaipara Flats Road to

turn south onto SH1. Rather, it counts the number of gaps sufficiently large to undertake

such a manoeuvre, and the number of vehicles that each gap should safely allow to turn.

17. The software is written using Excel/VBA (Visual Basic for Applications—the Microsoft Office

macro language). It uses spreadsheets to manage parameters and provide detailed outputs.

All logic is written in VBA.

3.3. Additional Information

Some of the information required is provided in the AEE and Operational Traffic Assessment Report

but these lack details about the origin and destination required to complete the model. To obtain

the rest, I approached NZTA and received the additional information required. This predominantly is

a breakdown of destinations of traffic entering the roundabout and entering Kaipara Flats Road.

Some other actual and apparent discrepancies in the Operational Traffic Assessment Report traffic

volumes were also resolved. The additional information is repeated in Appendices 1 and 2.

3.4. Base Model

The following outlines the key assumptions in the Base Model.

Southbound bunching

Target speed

5% 80kph

10% 90kph

Remainder 100kph

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Vehicle Gaps

Safe gap between vehicles 1.5 sec *

Safe gap before turning from Kaipara Flats Road

to SH1 southbound

7 sec

Safe Gap before entering the Roundabout 5 sec

* The Road Code says 2 sec but I suspect that this is not widely followed.

Warkworth Lights

Cycle 100 sec

North bound component 60 sec

(Set to be sufficient for all north bound traffic to

avoid significant queuing)

Traffic volumes at Roundabout

Aggregate

To

WW

To

MW

To

North

From North (SH1) 756 524 232 0

From Warkworth 1231 0 502 729

From Motorway 525 258 0 267

Total 2512 782 734 996

Notes:

1. These volumes are obtained from the NZTA Additional Data - Appendix 2

2. The traffic volumes at Kaipara Flats Road are assumed to be the same as those north-

bound from the roundabout. But note that NZTA's Saturn model assumes an additional

approx 100 vehicles will join SH1 north-bound between Hudson Rd and Kaipara Flats

Road.

Base Model Result

Gaps available for Kaipara Flats Road Traffic to turn onto SH1 southbound

Base Model Average Gaps Standard Dev Gaps Average Vehicles

19 3.8 33

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This compares with the additional data provided by NZTA (Appendix 1) which shows an average of

34 vehicles make this turn in the busy hour. i.e. The intersection can handle the incoming 34

vehicles just under half of the time (actually 40%).

Note: The impact of applying a degree of randomness to the ex Kaipara Flats Road traffic will likely

worsen the performance of this intersection.

3.5. Sensitivity Analyses

Safe gap between vehicles (on motorway / open road)

Base Model + Safe gap

between vehicles

Average Gaps Standard Dev

Gaps

Average Vehicles

1.5 sec (Base model) 19 3.8 33

2.0 sec 15 3.7 27

4.0 sec 1 0.6 2

The 2 sec scenario is in line with the Road Code recommendation for dry weather and 4 sec for wet

weather. Clearly there is a serious problem in wet weather!

Safe gap for turning from Kaipara Flats Road to SH1 southbound

Base Model + Safe gap

before turning from

Kaipara Flats Road to

SH1 southbound

Average Gaps Standard Dev

Gaps

Average Vehicles

5 sec 41 5.2 86

6 sec 28 5.1 52

6.5 sec 23 3.9 39

7 sec (Base model) 19 3.8 33

7.5 sec 16 4.0 26

8 sec 12 3.1 20

9 sec 9 3.1 14

10 sec 7 2.6 9

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This shows for each modelled gap, that there are quite large number of gaps that are of slightly

shorter duration than that gap. This raises the possibility that if traffic is waiting to turn some people

will take risks and attempt to turn when the gap is a little small with a consequential risk of

accidents.

Increased Traffic

Add 9% to the traffic levels in all directions—equivalent to 2 years growth of 4.4% compounded.

Average Gaps Standard Dev

Gaps

Average Vehicles

Base model 19 3.8 33

9% Traffic increase 14 3.3 24

This is showing that even a small increment in the traffic above projected 2026 levels results in the

Kaipara Flats Road / SH1 intersection backing up on Kaipara Flats Road. This finding has significant

ramifications should the opening of the motorway be delayed and the "base-line" traffic levels are

therefore higher than modelled.

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3.6. Appendix 1 - Additional Data from NZTA - Kaipara Flats / Sh1 Intersection

Traffic flows

The following was supplied by NZTA. From further emails, I understand that each rectangular box is

interpreted as—light vehicles on top, heavy vehicles on bottom.

3.7. Appendix 2 - Additional Data from NZTA - Roundabout Traffic flows

The following was supplied by NZTA.