Optimization for Front Distance of Speed Limit Sign at Tunnel Entrance and Converging Chevron Marking Parameters

Setting up deceleration markings and speed limit signs in front of the tunnel entrance is a very important means of traffic safety. Firstly, in view of the good application effect of the converging chevron marking but the lack of systematic explanation, with reference to the deceleration marking settings and cases at home and abroad, and according to the extensiveness and effectiveness, the preliminary parameters of the converging chevron marking are determined. The combination scheme of preliminary parameters is simulated by Uc-win/road, and the converging chevron marking with lateral width of 3 m, angle of 60°, flash rate of 6–8 hz and linewidth of 30–40 cm can better satisfy the driver’s static and dynamic visual perception. Secondly, considering that the front position of the speed limit sign is the key to affect its effect, based on the driver’s visual recognition and braking mechanism, the calculation methods of recognition distance and braking distance are derived, and the minimum front distance model of speed limit sign is put forward. At the same time, the method of cooperative arrangement of markings and signs is given. The research results can provide a reference for the formulation of the marking scheme of the speed control class at the entrance of the tunnel.