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Overview
November 2002
ISA across Europe
isa- UKintelligent speed adaptation
isa- UKintelligent speed adaptation
Trials around Europe - S
S
Active accelerator
Warning system “speed checker” Umeå
Sweden
Swedish findings and strategy Accident prediction in line
with earlier UK report National map to be created ISA will be fitted to SNRA
fleet Agreement to be secured
with car industry by 2005 to fit all new vehicles as of 2010
If no agreement is obtained, then the Minister has said he will push for a directive
ISA around Euope – NL & DK
50 km/h - you are driving to fastDK o
NL
Driver acceptability and Technical possibilities
Comparison of different designs
New projects in:
France (with involvement of Renault and Peugeot/Citroen)
Belgium (2 projects)
UK research on ISA DETR funded External Vehicle Speed Control (EVSC) project,
1997-2000 Develop a technical specification of a future system Assess legal implications and acceptability Study driver behaviour Predict accident savings and side effects (congestion, fuel
consumption, emissions) Design an implementation strategy
DfT funded ISA project, 2001-05 Field trials with 20 vehicles Further experimental work Technology development Motorcycle and large truck demonstrators
Driver behaviour with ISA
On-road trials in EVSC (external vehicle speed control)
72 drives 42 mile route Route covered all road
categories and all speed limits except 20 mph
2 ISA variants studied — voluntary and mandatory
Speed profile (mandatory system) in rural area
0
10
20
30
40
50
60
70
4 5 6 7 8 9 10Distance along route (miles)
Sp
eed
(m
ph
)
Without ISA
With ISA
roundabout
village (40mph)
village (40mph)
Negative interactions and conflicts
Run 1Run 2
Run 3
Mandatory
Voluntary
Baseline
0
5
10
15
20
25
Findings from on-road trials Driver speed was mostly dictated by
road geometry and traffic ISA most effective in urban areas/rural
villages Drivers thought the voluntary system
was preferable Drivers did not feel “out of the loop” or
exhibit signs of being so
Accident Prediction and Implementation Path
Changes in distribution of speeds
Advisory speed limiter:change in mean speed
0
0.01
0.02
0.03
0.04
-3 -2 -1 0 1 2 3
Fre
qu
ency
Norm Dist
Translation
Mandatory speed limiter:change in shape ofdistribution
0
0.1
0.2
0.3
0.4
0.5
0.6
-3 -2 -1 0 1 2 3
Fre
qu
ency
Norm Dist
Transformation
Formulae used for accident prediction
Mean speed:For each 1 mph change in mean speed the change in accident risk is as follows (derived from Finch et al., 1994): Low estimate 3.75% Best estimate 5.00% High estimate 9.70%
Speed variance:The formula applied for the relationship between speed variance and risk was derived from West and Dunn (1971) and is:
y = 0.0139x2 + 0.0140x
where y is relative riskand x is the speed difference of a vehicle from mean speed in mph
Predicted accident reduction from ISA for GB Advisory:
information only Driver Select:
voluntary control Mandatory:
speed limited all the time
Fixed:limits as now (posted)
Variable:+ lower where needed
Dynamic:+ lower when needed
Speed Limit System Intervention Level
Fixed Variable Dynamic
Advisory 10% 10% 13%
Driver Select 10% 11% 18%
Mandatory 20% 22% 36%
59%reduction
in fatal accidents
Other benefits
Annual saved fuel consumption:Petrol £198mDiesel £117m
Costs
Information supply Create digital road maps Maintain road maps Distribute road maps (Broadcast current speed limits) On-board system to locate vehicle
Control on the vehicle HMI
B/C ratios for alternative versions of ISA
Low GDP Growth High GDP Growth System
Fixed Variable Dynamic Fixed Variable Dynamic
Advisory 5.0 5.3 7.0 6.9 7.2 9.6
Driver Select 3.7 4.0 6.1 5.0 5.4 8.3
Mandatory 7.4 8.0 12.2 10.0 10.9 16.7
2000 2020
The recommended implementation scenario from the EVSC project
Voluntary usage
2019Mandatory usage
Manufacture 2013Production
2010
Standards
Standards enacted
2005
Research
Decision
This gives time for implementing dynamic ISA
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