Influencing Factor Analysis of Freeway Work Zone Capacity and Its Estimation Model

Various factors that influence freeway work zone capacity have been found in recent decades. However, not all factors have great influence on capacity and the influence degree of each factor to the capacity has been given little attention. In this article, grey correlation analysis was used to study the correlation degree of each influencing factor to work zone capacity and thus find the key influencing factors. Then a multiple regression model was established to estimate capacity for work zones, which provided a functional relationship between work zone capacityand several key independent factors. The grey correlation analysis results indicate that number of open lanes, speed, proportion of heavy vehicle, number of closed lanes, lateral distance to the open lanes, work zone length, time of day, location of closed lanes, and grade and intensity of work activities all have high correlation degree with work zone capacity with minimum value of 0.5695.