In the period 1999-2002 the Swedish National Road Administration conducted a large-scale field test with Intelligent Speed Adaptation (ISA) in urban traffic in four Swedish cities. Approximately 5000 vehicles were equipped with different ISA systems to help prevent the drivers from exceeding speed limits. The objective of the test was to learn more about driver attitudes to ISA and how drivers use the systems, impact on road safety and environment, and the integration of the systems in the vehicles.