Japanese Projects/Systems
Japan is leading all other countries in the implementation of a large-scale traffic control system that uses in-vehicle technology. The reason for their lead is due to their need for such systems. Over vast portions of metropolitan areas in Japan, the average speed is below 16.1 km/h (10 mi/h) during much of the daytime hours. The small geographic area and large population has led the Japanese government to install traffic control systems in all the large cities and on most urban and interurban freeways. These systems employ the latest technology, such as fiber-optic communications and in-color light-emitting diode (LED) changeable message signs displaying both text and graphics. Japan has invested in the development of driver information systems. Over 50 corporations have collaborated to develop in-vehicle systems that are marketed as units to be purchased by individuals who use the governmental road network system. The main ITS initiatives currently are road/automobile communication system (RACS), advanced mobile traffic information and communications system (AMTICS), and vehicle information and control system (VICS). Within RACS, the Ministry of Construction (MC) promoted and funded the Digital Road Map Association. This group was given the task of preparing and maintaining a national digitized road map data base. The results of this work are available on compact disc in a standard format. This format is used by both RACS and AMTICS, as well as by the various manufacturers of autonomous vehicle navigation systems (Ervin, 1991).
RACS
RACS is sponsored by the Public Work Research Institute of the MC, the Highway Industry Development Organization (HIDO), and 25 private companies. The system consists of vehicles equipped with dead reckoning navigation systems, roadside communication units (beacons) that are distributed throughout the road network (about 2 km (1.24 mi) apart), and a control center. There are three types of roadside beacons: Type 1 transmits location to the vehicle to zero-out cumulative navigation errors; Type 2 transmits, in addition to location, congestion and other traffic information; and Type 3 provides two-way communications with the vehicle so that information about the vehicle (e.g., location, automatic debiting of tolls, etc.), as well as emergency calls, can be transmitted to the control center. The MC recently announced a major beacon installation program, consisting mostly of Type 1. At present, there are about 1,000 beacons around Tokyo. Beacon installation is scheduled to proceed throughout Japan at a rate of about 10,000 beacons per year until 1994, with a gradual increase in the number of Type 2 and Type 3 beacons. Travel-time savings of 3 to 5 percent are expected, representing a significant reduction in fuel consumption and air pollution.
AMTICS
AMTICS is sponsored by the National Police Agency (NPA), the Ministry of Posts and Telecommunications (MPT), the Japan Traffic Management and Technology Association (JSK), and 59 private companies. It employs in-vehicle equipment similar to that of RACS, with the exception of the communication interface. The AMTICS data link is essentially a one-way means of broadcasting traffic data from a cellular system of terminals. It is intended to convey a wide variety of information, including congestion information, travel-time predictions, traffic regulations, railway timetables, and special events advice. This information is available at static terminals at railway stations, hotel lobbies, etc., as well as in the vehicle. A large-scale test of AMTICS was held in Osaka in 1990, and the results suggest that an individual travel-time reduction of about 7 percent could be achieved with in-vehicle navigation systems that provide congestion information to the driver. This would amount to individual travel-time savings of about $300 million if all cars were equipped in the Osaka area, with similar savings to the community because of reduced congestion. For more information on the AMTICS system, see papers by Okamoto (1988), Okamoto and Nakahara (1988), or Okamoto and Hase (1990).
VICS
VICS is a new program formed under the combined direction of the MPT, MC, and NPA, with the goals of resolving the competition between RACS and AMTICS and defining a common system using the best features of both. This venture is meeting with some opposition by those who feel that the competition between the two systems is improving both. A digital micro cellular radio system has been proposed to provide two-way road-vehicle communications and location information, essentially combining the tools used by each respective system. Although VICS may have a long-term future as part of an integrated driver information system for Japan, it will take some years to implement. In the meantime, a common RACS-AMTICS system using RACS Type 1 beacons and the broadcast of information to drivers via their FM car radios (like Radio Data System-Traffic Message Channel (RDS-TMC)) is the likely direction for further development.
Until now, traffic condition information was fed to drivers over the radio or through a supplemental system such as those mentioned above. However, most Japanese prefer to plan their own navigation routes rather than blindly follow directional arrows on an in-vehicle display (as is the case for the Autoguide systems used in the U.K.). The trend of opposition to blind direction following was researched by Schraagen (1990). The effect of "planning" routes while the vehicle is in motion on road safety has not yet been investigated in depth by the Japanese. This lack of investigation seems to be a trend in the development of Japanese systems.
Japanese systems tend to be put on the market with displays that are very detailed simply because the technology exists to do so. The litigation system in Japan gives some leniency for this type of system development and even for unsafe designs.
A Nissan system
A digital map-based system is sold with the Nissan Cedric, Gloria, and Cima models in Japan. It is similar in design to the ROGUE and TRAVELPILOT discussed in the previous section. A paper by Tanaka, Hirano, Nobuta, Itoh, and Tsunoda (1990) describes some of the interface aspects of this system. These aspects include: