This research was a "scan team" effort jointly sponsored by the Federal Highway Administration (FHWA), the American Association of State Highway and Transportation Officials (AASHTO), and the Transportation Research Board (TRB). During a two-week period in May 1998, the team visited with transportation officials in Gothenburg, Sweden; Frankfurt, Cologne, and Bonn, Germany; Paris, France; and London and Birmingham, England to identify noteworthy practices and technologies that may have value in the United States.
Intelligent Speed Adaptation (ISA) monitors the difference in speed between a vehicles current speed and its suitable speed. Corrective action can then be taken, for example, if the vehicle is traveling too fast for the current speed limit. Road beacons are used to transmit a signal to the car and warn the driver. The systems can also be automatic. A test of a prototype system was conducted in Eslov, Sweden, in which vehicles where limited to 50km/hr. Once the speed was exceeded drivers experienced resistance in the accelerator and where unable to increase speed further. The test drivers indicated that the system was well received as a safety control feature and that it was not an unpleasant control or source of irritation. Behavior studies also showed that the interaction between the test drivers and other road users improved.