Performance Based Standards

Sogol Kharrazi

Spectrum of Regulatory Principles

Principle based regulations

• Do not include quantified limits and are specified very broadly in

terms of objectives.

Prescriptive regulations

• Outline specifically how an objective should be achieved with

explicitly defined and quantified mandates.

Performance based regulations

• A regulatory principle between the two abovementioned extreme

approaches.

• Specific performance criteria/measures with quantified required

level of performance

• More precise than principle-based regulation, but provides more

flexibility than prescriptive regulations, encouraging innovations

Heavy Vehicles Regulations

Prescriptive regulations

• Predominant regulatory principle for regulation of heavy vehicles

• Setting limits on the vehicle weight and length

Performance based standards

• Standards specify the performance required from vehicle operations

rather than mandating how this performance should be achieved.

• It has been implemented in Australia, Canada, and New Zealand

• Each standard consists of three parts:

• Performance measure

• Acceptable performance level

• Test method

Performance Based Standards for

High Capacity Transports in Sweden

Project Objectives

• Identification of performance based standards, suitable for Sweden

• Proposal of an assessment procedure

• Proposal of an implementation method for the new regulation

• Identification of efficient HCT vehicle types

Project Consortium

Research Institute/University

• Swedish national road and transport research institute (project leader)

• Chalmers University of Technology

Industry

• Volvo Group Trucks Technology

• Scania

• Parator Industri AB

Authorities

• Swedish Transport Agency

• Swedish Transport Administration

PBS - Safety and Maneuverability

• Traction: The heavy vehicle should be able to start motion, maintain

motion and attain a desirable level of acceleration.

• Tracking: The rear end of the vehicle and all the units within the vehicle

combination should follow the path of the front end of the vehicle with

adequate fidelity.

• Stability: The vehicle should be stable, attain directional control and

remain upright during maneuvering.

• Braking: The vehicle should safely attain a desirable level of deceleration

during braking.

PBS - Safety and manoeuvrability

Traction

Performance measure Influential infrastructure feature

Startability

Measure of vehicle ability to commence from

rest on an upgrade road

Road grade

6-8% main roads, 10% minor roads

Friction (winter maintenance)

0.35 main roads, 0.25 minor roads

Gradeability

Measure of vehicle ability to maintain

acceptable speed on an upgrade road

Road grade

6-8% main roads, 10% minor roads

Friction (winter maintenance)

0.35 main roads, 0.25 minor roads

Acceleration capability

Measure of vehicle ability to accelerate from

rest with an acceptable level of acceleration

Friction (winter maintenance)

0.35 main roads, 0.25 minor roads

PBS - Safety and Maneuverability

Tracking

Performance measure Influential infrastructure feature

Low-speed offtracking/swept path

Measure of deviation of the towed units from

the prescribed path in a tight turn at low

speeds

Roundabout dimensions (outer and inner circles)

12.5 m - 2.5 m

Intersection dimensions (available width in a 90° turn)

8.5 m

Frontal swing

Measure of deviation of front outer corner of

the vehicle from the prescribed path in a tight

turn at low speeds

Roundabout dimensions (outer and inner circles)

12.5 m - 2.5 m

Intersection dimensions (available width in a 90° turn)

8.5 m

Tail swing

Measure of deviation of rear outer corner of

the vehicle units from the prescribed path in a

tight turn at low speeds

Roundabout dimensions (outer and inner circles)

12.5 m - 2.5 m

Intersection dimensions (available width in a 90° turn)

8.5 m

PBS - Safety and Maneuverability

Tracking (cont.)

Performance measure Influential infrastructure feature

Tracking ability on a straight path

Measure of deviation of the towed units from

the prescribed path on an uneven straight

road with a crossfall

Lane width

3.5-3.75 m highway, 3.0-3.75 m main roads, 2.75-3.25 m minor roads

Crossfall

2.5-5.5%

High-speed steady-state offtracking

Measure of deviation of the towed units from

the prescribed path in a turn at high speeds

Road curvature

Minimum 100-1200 m depending on speed limit

Lane width

3.5-3.75 m highway, 3.0-3.75 m main roads, 2.75-3.25 m minor roads

High-speed transient offtracking

Measure of deviation of the towed units from

the prescribed path in a sudden manoeuvre

at high speeds

Lane width

3.5-3.75 m highway, 3.0-3.75 m main roads, 2.75-3.25 m minor roads

PBS - Safety and Maneuverability

Stability

Performance measure

Steady-state rollover threshold

Measure of maximum severity of the steady turn, i.e. lateral acceleration, which the vehicle can

sustain without rolling over

Load transfer ratio

Measure of the farness from wheel lift-off in a sudden manoeuvre

Rearward amplification

Measure of the amplification of motions (e.g. yaw rate or lateral acceleration) in the rearmost unit in a

sudden manoeuvre

Yaw damping coefficient

Measure of quickness of decay of towed units oscillations after a sudden manoeuvre

Friction demand of steer tyres

Measure of excessive understeering risk, i.e. demanded friction at steer tyres, to overcome the

resistance of other axles, in a tight turn at low speeds

Friction demand of drive tyres

Measure of jackknife risk, i.e. demanded friction at drive tyres, to overcome the resistance of trailer

axles, in a tight turn at low speeds

PBS - Safety and Maneuverability

Braking

Performance measure Influential infrastructure feature

Braking deceleration

Measure of stopping distance

Friction (winter maintenance)

0.35 main roads, 0.25 minor roads

Braking efficiency

Ratio of achievable deceleration to the ideally

supported deceleration by the tyre/pavement friction

Friction (winter maintenance)

0.35 main roads, 0.25 minor roads

Braking stability on a straight path

Measure of required space during a heavy brake

Lane width

3.5-3.75 m highway, 3.0-3.75 m main roads, 2.75-3.25 m minor roads

Braking stability in a turn

Measure of required space during a heavy brake in

turn

Road curvature

Minimum 100-1200 m depending on speed limit

Lane width

3.5-3.75 m highway, 3.0-3.75 m main roads, 2.75-3.25 m minor roads

Braking stability on a split friction surface

Measure of controllability by the driver when it is

braked on a road with split friction

Friction (winter maintenance)

0.35 main roads, 0.25 minor roads

Parking ability on a grade

Measure of ability to stay still on a graded road

Road grade

6-8% main roads, 10% minor roads

PBS - Infrastructure

Pavement

• Limiting the axle loads, widely used approach

• Current knowledge is not sufficient to estimate effects during passes of

multiple heavy loads

• Bearing capacity of roads differ very much during a year

Bridge

• Primary part of the infrastructure that put restrictions on the axle load

• In Sweden, bearing capacity calculation of bridges is based on 14

reference vehicles, one possible approach to account for HCT is

considering more reference vehicles

• Bridge formulae are used in e.g. Australia and United States

Other Infrastructure Aspects

Tunnels

• Emergency parking space requirements

• Turning possibilities and reversing abilities in case of emergency

• Risk of fire

Safety barriers

• H4b: the highest containment level of barriers in the European standards

• H4b: an impact test with a 30 ton rigid truck, or 38 ton articulated vehicle,

with an impact speed of 65 km/h and an impact angle of 20°

Road service

• Parking and rest areas

• Driver fatigue is the cause of an essential part of single vehicle accidents

with heavy vehicles

PBS - Environment

The existing European regulations on emissions and

noise are already performance based

Euro VI emission limits (engine-based)

Vehicle & tyre noise

CO

(mg/kWh)

THC

(mg/kWh)

NMHC

(mg/kWh)

CH4

(mg/kWh)

NOX

(mg/kWh)

NH3

(ppm)

PM mass

(mg/kWh)

PM number

(#/kWh)

Compression Ignition

(WHSC) 1500 130 400 10 10 8.0 x 1011

Compression Ignition

(WHTC)4000 160 460 10 10 6.0 x 1011

Positive Ignition (WHTC) 4000 160 500 460 10 10 6.0 x 1011

Heavy Vehicle Normal Tyre Traction Tyre

Noise limit [db] 82, 81, 79 73 75

PBS - Environment

• No fuel consumption/CO2 regulation for heavy vehicles

is in effect in Europe yet.

• The Commission has set out a strategy to curb CO2

emissions of heavy vehicles and has developed a test

procedure to measure their fuel consumption and CO2

emissions.

Tests & Simulations

• A selection of vehicle combinations, as representatives of

the current fleet in Sweden and prospective HCT vehicles

• Swedish road characteristics will be considered in

deciding test maneuvers

• To investigate the correlation between the candidate

performance measures

• To investigate the correlation between the performance

on high and low friction surfaces

• To determine a safe level of performance for the selected

performance measures

Vehicle Combinations List

Heavy Vehicle Combination Axle configurations

1 Tractor-SemitrailerTR1+1-ST3

TR1+2-ST3

2 Tractor-Link trailer-Semitrailer (B-double)TR1+1-LT2-ST3

TR1+2-LT2-ST3

TR1+2-LT3-ST3

3 Tractor-Semitrailer-Center axle trailerTR1+1-ST3-CT2

TR1+2-ST3-CT2

4 Tractor-Semitrailer-Dolly-Semitrailer (A-double)TR1+1-ST3-DY2-ST3

TR1+2-ST3-DY2-ST3

5 Tractor-Semitrailer-Full trailer TR1+2-ST3-FT2+2

6 Tractor-Link trailer-Link trailer-Semitrailer (B-triple)TR1+2-LT2-LT2-ST3

TR1+2-LT3-LT3-ST3

7 Truck-Center axle trailerTK1+2-CT2

TK1+3-CT3

8 Truck-Full trailerTK1+2-FT2+2

TK1+2-FT2+3

TK1+3-FT2+3

9 Truck-Dolly-SemitrailerTK1+2-DY2-ST3

TK1+3-DY2-ST3

10 Truck-Center axle trailer-Center axle trailerTK1+2-CT2-CT2

TK1+2-CT3-CT3

11 Truck-Dolly-Link trailer-Semitrailer (Truck B-double)TK1+2-DY2-LT2-ST3

TK1+2-DY2-LT3-ST3

TK1+3-DY2-LT3-ST3

THANK YOU!sogol.kharrazi@vti.se