Is Heavy Vehicle Percentage (HVP) a Necessary Factor for Predicting Highway Work Zone Capacity?

The intent of this paper is to demonstrate the heavy vehicle percentage is not a necessary factor for predicting highway work zone capacity. First, based on the analysis of a multiple regression model in previous study, an improved model introduced the concept of passenger car equivalent (PCE) and defined the effect index (EI) for evaluating the importance of different factor affecting the work zone capacity. The smaller EI of heavy vehicle percentage indicated that the heavy vehicle percentage was not the key factor when estimating the work zone capacity. Second, this paper also ran simulations to compare the travel time when the passenger car equivalent volume remained in the same. The results showed only 5% of the difference in the travel time varied with the heavy vehicle percentages. At last, a new model without the input of heavy vehicle percentage was further developed. Its performance had been proven to be better than that recommended in highway capacity manual (HCM).