Select Committee on Transport, Local Government and the Regions Appendices to the Minutes of Evidence

Annex 6


  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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