Heavy vehicles contribute to a significant component of all transportation in cargo terminals. On uphill sections, the heavy vehicles mixed drive with small cars affecting the traffic efficiency. Speed reduction is the index to reflect the mutual influence. In alignment design, the speed reduction is used to determine the critical length of grade and crash involvement rate has been considered. However, limited research results have been reported at this point concerning speed reduction and traffic efficiency. Firstly, traffic data including traffic volume, timely speed, and headway time were collected through field experiments. The traffic efficiency was derived from traffic volume and average speed. After this, the modeling between speed reduction and traffic efficiency was processed. The correlation between speed reduction and traffic efficiency was therefore verified. Finally, the optimum speed reduction concerning traffic efficiency was given. The findings can provide a reference for profile design, leading to high-efficiency road system.

CICTP