Despite the movement of safe traffic by the Korean government to reduce deaths in traffic accidents, the casualties increase year by year. In particular, more and more accidents and casualties are reported from car collisions from the back of the vehicles parked for managing traffic accidents on the road, cleaning main roads and medial strips, repairing roads. In order to response to these accidents, the government should take protective measures for road users. In the last decade, seventy-one cases have been reported to occur during highway repair and maintenance. As a result, eight persons were killed and seventy-six were injured, showing the high death rate of 11.3 percent. Therefore, it seems urgent to take some actions against it. The United States and European countries legislate that vehicles of road repair and maintenance should be mandatorily equipped with shock absorber at the back. Korea, however, does not have such legislative measures, which are needed at this time to protect workers on the road. This study compares the performance of the traditional shock absorber for road maintenance vehicles with that of the rear safety guard using air bag, manufactured in accordance with related laws in Korea. Based on the results of the 60km/h rear collision test, this paper proposes improvements in related laws and regulations in an attempt to reduce casualties.