Estimation of PCE values for hill roads in heterogeneous traffic conditions

Abstract

The traffic operations of hill roads are an important aspect that needs to be understood. In order to ascertain the traffic performance, estimating the PCE values and capacities are critical. PCE values are dynamic and vary with small change in any of the influencing characteristics. These values and roadway capacities vary with the estimation method adopted in the analysis. This study aims to understand the influencing factors for estimation and eventually estimating the PCE values of different vehicle types on hill roads. This study includes a review of various methods for estimating PCEs followed by data collection on hill roads of the northeastern state of India (Meghalaya state). PCE values are estimated based on the three important methods identified. These are, (i) Speed-area method, (ii) modified density method, and (iii) area occupancy method. For the data sets analyzed under the prevailing traffic mix, the volumes were very low and the vehicles are predominantly cars, SUVs and trucks with negligible proportion of two wheelers. PCE values obtained from speed-area method are on the higher side for heavy vehicles and on lower side for motorized two wheelers compared with the modified density method and area occupancy methods. Modified density method and area occupancy methods show different PCE values yet these two methods confirm that in hilly terrains having low level of traffic volume, range of PCE values for heavy vehicles and motorized two wheelers decreases by a considerable extent.

Keywords:

• PCE
• hill roads
• capacity
• area occupancy
• modified density