2008 年 74 巻 738 号 p. 250-258
The Meihan highway linking Kameyama in Mie Prefecture and Tenri in Nara Prefecture is one of most accident-prone areas in Japan. Representative accident factors that have been identified for the Meihan highway are chronic speeding and complex road alignments, including many sharp curves and steep slopes. One particular section is known as the “Omega curve” as the road shape is similar to the Greek character “Ω”. In this study, the probable effects of proposed plans to improve the road alignment of the Nakahata section are investigated by performing driving simulations to identify typical hazards, ranging from traffic conflicts to vehicle accidents. It was found that incidents that begin as a minor traffic conflicts can frequently escalate to become a fatal accidents. It was also found that improved road alignment generally reduces the required tire forces. For typical traffic conflict patterns reproduced using the driving simulator, it was found that road alignment resulted in considerable improvements in safety indexes which are effective indicators for the occurrence of rear-end collisions.