Essays on Travel Demand for Toll Roads



Kweun, Jeong Yun

Journal Title

Journal ISSN

Volume Title



Road pricing, a fee related to using a road, is one of the main instruments used in transport regulation to manage both externalities such as congestion and revenue for infrastructure investment. As road pricing attracts ongoing interest from policymakers, there is a gap in the literature examining road pricing and its impacts on traveler behavior and demand for priced limited access roads (or toll roads). This dissertation examines policy-related empirical questions regarding the relationship between road pricing and travel demand in a three-essay format and aims to provide empirical evidence regarding two main areas of ongoing road pricing experiments in the United States: the road pricing of interstate highways and the conversion of existing high-occupancy vehicle (HOV) lanes to high-occupancy toll (HOT) lanes. The first essay, Road Pricing Elasticity of Demand – A Survey, centers around one of the main parameters of demand, namely price elasticity of demand, and examines the sources of variation in road pricing elasticity of demand through an in-depth survey of 24 studies published between 1981 and 2015 on travel demand for toll roads. The results show that potential sources of variation include the method of estimating road pricing elasticity of demand, characteristics of facilities, types of facilities, vehicle types examined, payment methods, types of data analyzed, such as stated or revealed preference, and importantly, the level of road pricing implemented in place. The second essay, Road Pricing Elasticity of Demand for U.S. Toll Roads – a Dynamic Panel Data Analysis, examines both the traveler’s responsiveness to road pricing and whether functional class and geographic coverage of the toll facility explains the variation in estimates of road pricing elasticity of demand. The analysis of travel demand data for 64 U.S. toll roads in 15 states from 2004 to 2013 shows that the short-run price elasticity is smaller for urban toll roads than intercity roads and smaller for interstate than non-interstate toll roads. One explanation is that despite the availability of free alternative routes in urban areas, free routes are not practical to use due to higher travel cost and reduced travel time savings because of congestion in urban areas. The third essay, Impact of HOV-to-HOT Conversion on Drivers, focuses on the impact of converting high-occupancy vehicle (HOV) lanes to high-occupancy toll (HOT) lanes on carpoolers. Taking the I-85 HOV-to-HOT conversion project in Atlanta, Georgia as an empirical case, the analysis used a publically available dataset called the I-85 Corridor Household Travel Survey, which took place before and after the conversion of the facility. The binary logit estimators show that drivers in medium- to high-income groups, younger age cohorts, being white, having smaller household size, and taking trips for child care purposes were more likely to drive in the express lanes. Females driving to take care of their children were less likely to use the express lanes, but the result was not statistically significant.



HOV-to-HOT conversion, Price elasticity of demand, Road pricing, Toll road, Travel demand