1991年冬,312国道江苏境段建成通车后,交通条件明显改善,车速提高、交通事故下降。由于路线穿越一些市郊村镇,为处理混合交通问题,在车行道两侧布置了1.5～2.5m宽度不等的硬路肩。其中:苏州外跨塘至硕放段长41km的硬路肩,采用上拌下贯式结构,使用效果更为理想,它在很大程度上分流了非机动车,对保障交通安全、提高道路的通过能力起了明显作用。然而,外跨塘向东至昆山段的42km,是以双层表面处治做硬路肩的,实际 In the winter of 1991, after the completion of the opening of the 312 State Road in Jiangsu Province, the traffic conditions were obviously improved, the speed increased and traffic accidents were reduced. Due to the route through some suburban villages and towns, in order to deal with the mixed traffic problems, hard shoulders with widths of 1.5-2.5m are arranged on both sides of the roadway. Among them, the 41km long shoulder outside the pond from Tongtang to Shuofang in Suzhou adopts the underslung structure with better effect, which diverts the non-motor vehicles to a great extent and ensures traffic safety and road improvement Through the ability played a significant role. However, outside the pond to the east of Kunshan section of 42km, is based on the double surface treatment hard shoulders, the actual