Two-Lane Highway Capacity Estimation Based on Geometric Features

Abstract The majority of roads in most countries are two-lane highways. These lanes quickly reach their capacity and must be upgraded on a regular basis. To do so, we must first determine the capacity of the street. The primary objective of this study was to determine the effect of carriageway width, the radius of the horizontal curve, and gradients on Passenger Car Unit (PCU) values as well as on capacity of two-lane undivided Highways, and more importantly, to develop a multiple linear regression model to determine the capacity of the highway when all of these factors are present, which has not been previously reported. Green shield’s model was used to estimate the capacity of each element for all thirty-six sections using flow and speed data. Different models were built using regression analysis to estimate capacity independently, and the combined model was developed as a result. It has been noted that with proportionate increases in carriageway width and radius of the curve, there is an equivalent rise in PCU values and highway capacity, providing improved comfort and safety to road users. It was also discovered that when the value of the gradient increases cause increase in PCU values but the highway capacity decreases, thereby increasing the vehicle operating cost. Where all of these characteristics are present simultaneously in a section, the resulting multiple linear regression model was proven to be appropriate. It is believed to be valuable to practitioners as well as in the development or revision of Indian highway capacity manuals.