Annex 6
TECHNOLOGY FOR
ENFORCEMENT
As well as traditional speed management methods,
such as road engineering using traffic calming and speed camera
enforcement, there are two emerging interventions using more advanced
engineering that can be highly effective in managing vehicle speeds.
These are advanced enforcement using digital cameras and vehicle
speed control.
Advanced Camera Enforcement
Following the proven effectiveness of conventional
speed cameras a more advanced enforcement system is now available
using a system of digital cameras and automatic number plate recognition
(ANPR). This detects and records the registration number of all
vehicles passing the first of two cameras on a route, and at the
second camera it determines whether any vehicle has passed between
them at an average speed in excess of the speed limit. Prosecutions
result if that is the case. The system has been successfully used
to improve speed limit compliance and reduce casualties on longer
stretches of main road. A notable example is in the Nottingham
Safety Camera Pilot where virtually complete compliance was achieved
on the major ring road into the city.
Vehicle Speed Control
For some time heavy goods vehicles, buses and
coaches have been required to have governors limiting them to
their maximum permitted speed. This does not address speeding
by these vehicles on roads with lower speed limits than their
governed maximum speed. Manufacturers have also offered vehicles
with cruise control that can be set to maintain a chosen maximum
speed. However, it is now technically possible to automatically
restrict vehicle speed to the speed limit in force on any given
road or to advise the driver of the speed limit, rather than just
limit maximum speed, using Intelligent Speed Adaptation (ISA)
technology.
Intelligent Speed Adaptation (ISA)
The results of a DETR research project on ISA,
entitled "External Vehicle Speed Control" (EVSC), completed
in 2000, suggest that if such systems were universally fitted
all injury accidents could be reduced by over one third (36 per
cent) using a mandatory dynamic system, and fatal accidents could
be reduced by over one half (59 per cent) using the same system.
In addition, fuel consumption could be reduced by up to eight
per cent.
ISA can take many forms, but there are three
basic levels of control:
Advisory. A driver is informed by an in-vehicle
device of the speed limit and/or when the speed limit is exceeded.
At all times the driver retains control of the vehicle speed.
Driver Select. A driver is informed by an
in-vehicle device of the speed limit and can choose whether he
wishes his vehicle to be limited to that speed. The driver may
also be able to select another speed (higher or lower) than the
posted speed.
Mandatory. A driver is informed by an in-vehicle
device of the speed limit and the vehicle is limited to that speed.
In some of the systems which are being developed, the driver may
be able to over-ride the system, but this should only be as a
temporary measure.
In addition, the speed limits to which ISA could
operate can be considered to be:
"fixed" those currently posted on the
road side.
"variable" similar to those currently
posted on the road side, but additional limits introduced according
to the position along the road where the existing limits are not
appropriate, eg at sharp corners, dangerous junctions. The limits
could also be increased where a section of road is safer.
"dynamic" they are varied according
to the location and the time of the day, eg outside schools when
children are arriving and leaving, in contra-flow systems on motorways,
in adverse driving conditions (fog, ice, etc)
The three-year research project was carried
out by the University of Leeds and the Motor Industry Research
Association (MIRA). It involved using a driving simulator, road
trials in an ISA vehicle, and computer modelling. In addition,
volunteers were interviewed about their perception of ISA as part
of the trials.
The project investigated the benefits, as well
as the risks associated with ISA. The simulator trials showed
some potential negative effects, smaller headways and turning
across traffic through smaller gaps, which would suggest a riskier
style of driving. However, these negative effects were not borne
out in the road trials (partly because the trial vehicle was the
only one equipped with ISA and tended to be one of the slower
vehicles on the open road). Drivers tended to report that they
adopted a more relaxed driving style and were more observant,
as they did not need to be checking their speed.
A second research project started at the beginning
of this year, again being carried out on the Department's behalf
by Leeds/MIRA. The prime objective of this project is to place
20 ISA passenger cars on the road with four groups of volunteers
for extended periods of time (six months at a time) and to measure
any changes in their driving behaviour over time. The ISA system
is expected to operate over a wide area, covering most of the
participants' normal driving. As part of the project, the ISA
vehicles will also be used together on sections of road to simulate
higher penetrations of ISA to observe the effect that this has
on the drivers of the ISA vehicles and other vehicles. It is anticipated
that the trials will begin in mid-2002.
In addition, the functionality of ISA devices
will be considered further, including communication and control
systems and the interface between the speed limiting function
and the speed limit information system.
The trials are designed to non-intrusive so
that the vehicles will look and behave like "normal"
cars apart from the ISA feature. This will be of the voluntary
type: drivers will be able to opt out of ISA speed limiting at
will via a button on the steering wheel, although the default
setting will be that ISA is on. Data will be logged automatically,
and data collection will be remote through a GSM (Group System
Mobile) cellular telephone link.
The system will also have a kickdown feature
so that sharp pressure on the accelerator will result in the ISA
going into standby, with the ISA resuming only when the driver
voluntarily comes below the speed limit. The speed limit and ISA
state will be indicated to the driver by a screen that will be
integrated into the dashboard.
It is intended to base the system on a commercial
digital road map and Global Positioning System (GPS), and provide
drivers with ISA support for a large percentage of their regular
driving, to include both the local area and the national trunk
road network.
Each trial will last for six months. The initial
month of driving will be without ISA activated; there will then
be four months of driving with ISA; and the final month will again
be without ISA. The design has been chosen so as to enable:
— The investigation of longer-term
changes during a prolonged exposure to ISA
— Comparison of driving with ISA to
driving without ISA
— Comparison of the initial non-ISA
period to the final non-ISA period to investigate whether ISA
has any carry-over effect on driving (this might be either a calming
effect in which drivers become more accepting of speed-limit compliance
or alternatively drivers may feel released from the pressure to
comply once ISA is removed)
The private motorist samples will be volunteers,
an equal number of males and females with an average annual mileage
exceeding 10,000 miles. Drivers who have been convicted of driving
under the influence of alcohol or other illegal substances, and
those who have been involved in more than two accidents in the
previous three years, will be excluded from taking part. However
it is the intention to include among the private motorists a group
of habitual speed violators, so that the effect of ISA on their
behaviours and attitudes can be studied.
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