Minimum clearance distance between interchange entrance and intersection entrance based on microscopic lane changing

Objective Improper spacing between interchange entrance and intersection entrance on distributed first-class highways will lead to potential safety risks, e.g., traffic disturbances and increased conflict; however, existing standards provide no clear guidance on this issue. To address this gap, this study develops a quantitative minimum clearance distance model, as well as proposes the recommendation of engineering-feasible clearance distance. Method First, the functional independence of interchange entrance and intersection entrance was analyzed. The applicable minimum clearance distance ranges for different acceleration-lane configurations were defined. Second, based on drivers' behavior in adverse conditions, the minimum clearance distance calculation model was established, consisting of recovery distance, sign perception distance, lane changing distance, and exit confirmation distance. The key model parameters were determined through field data. The theoretical minimum clearance distance values were then derived. Finally, a simulation model of section between interchange entrance and intersection entrance was constructed with VISSIM simulation software. The conflict rate served as the safety evaluation indicator to analyze the recommended minimum clearance distance with varying traffic demands; as well as validate the rationality of theoretical minimum clearance distance. Result On one-way three-lane mainline, the general values of minimum clearance distance at design speeds of 60 km/h and 80 km/h are 680 m and 880 m respectively. The traffic volumes significantly influence the minimum clearance distance. The required distance increases as the volume-to-capacity ratio rises. Conclusion The proposed model would effectively capture the spatial requirements between interchange entrance and intersection entrance. The recommended minimum clearance distance values show good engineering applicability, providing a practical reference for distributed first-class highway design.