Study on the Reasonable Spacing Between Adjacent Work Zones in the Same Lane of Mountainous Two-Lane Highways

In China, mountainous two-lane highways account for 10% of the total mileage and often serve as the only access to the smallest administrative units within a region. During major and medium maintenance operations, road bottlenecks formed by adjacent work zones lead to traffic congestion, delays, and secondary accidents. Therefore, this study analyzes the spacing arrangement of long-term work zones on mountainous two-lane highways to mitigate traffic impacts caused by road maintenance. First, the distribution spacing of work zones during maintenance operations was investigated, and five travel distances corresponding to vehicle acceleration/deceleration behaviors between adjacent work zones were defined to establish a model for reasonable spacing. Next, the reasonable spacing between adjacent work zones was determined based on measured vehicle speeds in mountainous areas. Finally, Vissim simulation validated the results, showing that the theoretical calculated value exceeds the critical threshold of 800 m. The recommended spacing range for adjacent work zones was determined to be 850–900 m.