Download ISA across Europe

isa- UK
intelligent speed adaptation
ISA across Europe
Overview
November 2002
Trials around Europe - S
S
Sweden
Warning system
“speed checker” Umeå
Active accelerator
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
NL
Driver acceptability and
Technical possibilities
DK
50 km/h - you are
driving toofast
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
70
Without ISA
With ISA
60
Speed (mph)
50
40
village
(40mph)
30
village
(40mph)
20
10
roundabout
0
4
5
6
7
8
Distance along route (miles)
9
10
Negative interactions and
conflicts
25
20
15
Baseline
10
Voluntary
5
0
Run 1
Mandatory
Run 2
Run 3
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
0.6
0.04
0.5
Frequency
Frequency
0.03
0.02
Norm Dist
Translation
0.01
0.4
Norm Dist
Transformation
0.3
0.2
0.1
0
-3
-2
-1
0
1
Advisory speed limiter:
change in mean speed
2
3
0
-3
-2
-1
0
1
2
3
Mandatory speed limiter:
change in shape of
distribution
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 risk
and 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
Intervention
Level
Speed Limit System
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 £198m
 Diesel £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
The recommended implementation
scenario from the EVSC project
Mandatory usage
2019
Production
2013
Standards enacted
Decision
2010
2005
2000
This gives time for implementing dynamic ISA
2020