The higher the road grade, the higher the safety standards considered in design and the higher the maintenance standards used. However, the management mode with fixed road section as the maintenance unit does not fully consider the unsafe situation caused by the combination of road surface and geometry design. The low maintenance standards of low-grade roads combined with poor geometry design and complex driving environment make low-grade roads a high-risk area for traffic accidents. Based on the five-year (2010~2014) accident data of mountainous highways in Chongqing, the comparative attribution analysis of expressways and general highways was carried out. Taking curve section as an example, a safety model based of force analysis without the risk of slippage is established. Skid number (SN) is used as the anti-skid performance index. With different Road radius and different pavement condition (skid number), the critical safe speeds without slipping are calculated. The calculations have verified the trend that the lower the road grade, the higher the requirements for anti-skid performance, and the impact of anti-skid performance on safe driving speed is proved significant. Comparing to the requirements of road maintenance standard, the maintenance standard of low-grade roads cannot meet their basic safety requirements. It is believed that the maintenance unit of the road should be defined according to the driving environment and geometry conditions, and the anti-skid performance should be added to the safety audit and the road maintenance standard. An interval assessment method for assessing the safety of road conditions is proposed, and some suggestions on design and management are proposed.

CICTP