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In 1990, The Japanese National Police Agency (NPA) planned a nationwide two-year research project including field experiments, “Travel Time Estimation and Prediction” aimed at realizing a reliable method of providing travel time information to drivers (1)*. The project was conducted by the Japan Traffic Management Technology Association and three system manufacturers (Sumitomo Electric, OMRON and Matsushita Communication) collaborated on research and experimental work. Several methods of estimating and predicting travel time were developed and evaluated in three major cities (Tokyo, Yokohama and Osaka). Four models, Sandglass, Delay Time, Auto Regressive and Neural Network Models were developed and evaluated using detector and license plate reader information, and field survey data in the three major cities. The first year evaluation results are described here.

Fiber-optic data links have been developed for use in vehicle navigation systems, especially for the communication of CD data. The links consist of transmitters, receivers, and cable assemblies. The transmitters, which include only LEDs, must have driver circuits on their exteriors. In the receiver section, a PD, an amplifier, and a TTL compatible comparator are all integrated into the custom designed IC which is hermetically sealed into an originally developed metal package. Small optical connectors and heat-resistant plastic fiber cords with sufficient reliability and good operability for automotive uses have also been developed.

A new double-layer valve seat insert has been developed for use in high performance diesel engine of passenger car. The seat layer is composed of a sintered alloy of a high wear resistance and a high heat resistance. The base layer is composed of a sintered alloy of a higher heat resistance than that of the seat layer. This double-layer valve seat insert was proven to have good wear resistance and heat resistance in a durability test on the diesel engine with a turbocharger system.