The External Vehicle Speed Control (EVSC) project has the aim of reviewing a broad range of factors related to the possible introduction of an automatic system to limit the top speed of road vehicles. No policy decision has been made on whether or not to move ahead with the implementation of such a system for the vehicles on Britain's roads. The project is intended as a piece of research to provide information on the likely benefits and costs associated with the variants of a speed-limiting system, on driver behaviour while using the system, on the network side effects of limiting vehicle maximum speed and on implementation scenarios. The research into EVSC is in line with the view expressed in the White Paper of July 1998 "A New Deal for Transport: Better for Everyone" that the capabilities of technology are changing very rapidly. The White Paper, in discussing technologies for enforcement, make specific reference to the potential for linking the technologies used in adaptive cruise control to geographic information systems in order to make speed limits self-enforcing. It was assumed at the outset that an EVSC system would have to be: * Cost-effective, * Acceptable, * Logistically feasible, and * Safe. This Executive Summary summarises the results of the Phase II of the project. This phase of work began in January 1998 and ended in May 1999. It was the main research phase of the project, following on from the introductory and preparatory work in Phase I (February to October 1997). Phase II covered work in the following areas: 1. Design of a prototype system-user interface (HMI); 2. Driving simulator experiments; 3. On-road trials; 4. Simulation modelling to predict network impacts of EVSC; 5. Assessment of implications of EVSC for the future UK vehicle fleet; 6. Review of preferred approach to implementation developed in Phase I; 7. Performance specification for EVSC; 8. Legal implications; 9. Links with other projects, both within and outside the UK. Of these work areas, (8) and (9) are to produce formal deliverables only at the end of Phase III, i.e. early in 2000. This document presents summaries of the major findings of Phase II. A list of the deliverables produced by the research team is included at the end of the document. These deliverables are available from the Institute for Transport Studies. The main objectives of Phase II were: 1. to study driver behaviour in controlled conditions; 2. to study driver behaviour in more natural, but less controlled conditions; 3. to estimate the impact of EVSC on network performance, fuel consumption and emissions; 4. to extend to work carried out in Phase I on implementation aspects. The study of driver behaviour in controlled conditions was carried out on a high-quality driving simulator, which allows the creation of carefully planned scenarios and assures that all the drivers are subjected to the same road conditions and traffic situations. The pre-planned scenarios can include deliberately risky situations. The study of driver behaviour in more natural conditions was carried out using a specially modified car. The car was equipped with an autonomous EVSC system that used Differential GPS (dGPS) and an on-board digital road map. For the investigation of traffic, emissions and fuel consumption effects, a micro-simulation model was employed. Three road networks were simulated: an urban network in both peak and off-peak conditions; a rural two-lane highway, and a motorway. The document groups the work that has been accomplished in a logical sequence. Part 1 covers the practical trials, including the design of the test vehicle, the laboratory (driving simulator) trials and the on-road trials. Part 2 covers the simulation modelling on network impacts. Part 3 summarises the integration work, i.e. the implications of EVSC for the future UK fleet, the investigation of the performance specification for EVSC, and the review of the implementation path.
Abstract