The number of people killed in road traffic accidents in Japan had increased from year to year until 1970 and the number of deaths and injuries recorded in the same year were 16,800 and 980,000, respectively, or a total of nearly 1 million casualties, resulting in the introduction of the phrase "traffic war." Under these circumstances, insuring traffic safety became a top priority social issue, and, as part of a national attempt to cope with this problem, the Fundamental Law Related to Traffic Safety Measures was enacted in 1970. Based on this law, the national and regional governments pursued comprehensive and powerful traffic safety policies and measures in various areas, including the improvement and provision of traffic safety facilities. As a result, the number of deaths and injuries from traffic accidents in 1979 was reduced to approximately 8,500 and 600,000, respectively, the former representing a decrease by nearly half that recorded in 1970.

Since 1980, however, the trend has reversed, and the number of deaths has followed an upward path;​ the death toll has exceeded 9,000 for 3 consecutive years from 1982 through 1984. A prediction study conducted by the Traffic Safety Policy Office of the Management and Coordination Agency in 1984 estimates the number of deaths will continue to rise and will reach approximately 10,600 in 1990. To suppress this increase in the number of deaths, legislation that reinforces the compulsory use of helmets for moped drivers and seatbelts is planned for enactment in the near future.