Research conclusions :(1) The design load should be appropriately increased According to the actual road conditions and the highest grade SS of the anti - collision should be adopted. (3 ) The anti - throwing network of full - closed form or semi - closed form can be determined according to the position of the highway bridge. (3) The anti - collision and anti - throwing network can be rebuilt according to the real engineering requirement, or the scheme of the more safe, reliable and operable strong rigid frame bridge can be used for the existing highway bridge.