Since 1950s

The Kansai Metropolitan Area extends through the cities of Osaka, Kobe and Kyoto, following Tokyo as a center of economic and cultural activities. From the 1950s to the 1960s, the Kansai area experienced overpopulation as a result of Japan's economic growth, resulting in various adverse consequences. In particular, an unexpectedly rapid increase in the number of vehicles worsened road conditions in the Osaka-Kobe area, severely affecting economic activities and urban life. In 1954, the national government launched the 5-year Road Improvement and Management Program to promote road development, and in 1956 the Law Concerning Special Measures for Highway Construction was enacted to ensure efficient operation of the toll road system.