Method of measuring travel time by using ultrasonic vehicle profile classifiers

As an approach to develop an effective real-time prediction system, a new system has been developed to measure the time used by vehicles to travel a certain section of a road. The system identifies special vehicles at the entrance and the exit of the section with ultrasonic vehicle classifiers. The first field experiment was made in 1986 at a section of 500 m length on the route 17 in Saitama Prefecture, and proved that the system was capable of measuring travel time. Further tests were conducted in 1987 and 1988 at the 1 to 3 km long sections of the route 17, and the maximum length of section applicable to the system was also studied. The conclusion of the tests was that the mean time for travelling a section of up to 2 km length has been obtained by using the system. Essentials of the tests are reported