Performance Based Standards - CLOSER | … grade 6-8% main roads, 10% minor roads Friction (winter...
Transcript of Performance Based Standards - CLOSER | … grade 6-8% main roads, 10% minor roads Friction (winter...
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 [email protected]