In order to prevent vehicles on the roads that access the distributed primary roads from entering the primary roads at a higher speed, an access section transition section should be provided between the primary roads and the access roads. Based on the analysis of the transition period of the access port and the connection between the access road and the main line, the setting conditions of the transition section based on the maximum longitudinal slope of the access road are proposed. According to the level of the access road, based on the driver's visual field characteristics, the vehicle Based on the principle of turning widening and the principle that the longitudinal slope of the access road is consistent with the horizontal slope of the first-grade highway, the recommended values of the geometric design indexes such as the width, access angle, corner radius and slope of the transition section of the first-level highway access are proposed. Based on the principle and the access angle of the transition section of the access port, the calculation model of the transition length of the access port is established, and the minimum length recommendation value of the transition section of the primary road access port based on the design speed of the access road is proposed.

CICTP