INTELLIGENT SPEED ADAPTATION (ISA). RESULTS OF LARGE-SCALE TRIALS IN BORLAENGE, LINKOEPING, LUND AND UMEAA DURING THE PERIOD 1999-2002

Between 1999 and 2002 the Swedish National Road Administration conducted a large-scale trial involving Intelligent Speed Adaptation (ISA) in four towns. Several thousand vehicles were equipped with voluntary, supportive and informative systems to help keep drivers from exceeding the speed limit. The aim of the trial was to learn more about: 1) driver attitudes and how they use the systems; 2) the impact on road safety and the environment; 3) the integration of the systems in vehicles; and 4) the prospects for Intelligent Transport Systems (ITS) on a large scale. Most of the actual field trial was carried out in 2001, when up to 5,000 vehicles, driven by over 10,000 drivers were in traffic. Numerous surveys and interviews were conducted throughout the trial period. All the data collected at the trial was compiled and analysed in 2002. The main findings were: 1) Better road safety without increasing travel time; 2) If everyone had ISA, there could be 20% fewer road injuries in urban areas; 3) High acceptance of ISA, and after the trial most test drivers were of the opinion that ISA should be compulsory in urban areas; 4) ISA vehicles were found to have a positive influence on surrounding traffic; 5) Minor differences between the systems, with an average speed reduction of 3-4 km/h on stretches between intersections; and 6) The systems must be improved to become more attractive. Based on the experience from the Swedish ISA project as regards implementation, evaluation, technology, information and the dialogue on the issues involved in a market introduction, several recommendations are provided.