In all the traffic accidents, bicycle related accidents and its casualties have taken a large proportion; especially at grade crossing, traffic accidents often happen between bicycles and vehicles, which is seriously impaired traffic safety.

• 交通事故中,自行车交通事故及其伤亡人数占较大比重,特别是在平面交叉口,自行车与机动车经常发生交通冲突,严重影响交通安全。