Abstract
This study analyses effects of heavy vehicles on uncongested traffic flow on intercity motorways. First, several definitions of the PCE (Passenger Car Equivalence) are reviewed and the problems on PCE are pointed out through the estimation of PCE values by speed levels at 43 locations on the Tomei expressway using traffic detector data. Second, to evaluate effects of heavy vehicles, the study proposes a 3-dimensional regression of flow, speed, and percentage of heavy vehicles as a function of the road alignment as well as visibility without introducing PCE.
