A Gini coefficient based evaluation on the reliability of travel time forecasting

Abstract

Traffic congestion is one of the most notorious troubles, one that undermines social costs in urbanized areas in the world. Because of the congestion problem, drivers are trying to find the shortest and most reliable paths. Regarding the reliability of travel time, there already exist a few measures, such as Standard Deviation, Buffer Time, and Buffer Index. However, they have fundamental limitations in calculation or in application.Therefore, we tried to apply the Gini Coefficient, which is a well-known measure of statistical dispersion, which describes the inequality of income or wealth distribution among a nation’s residents, as a new measure for evaluating travel time reliability.In order to verify the new measure, we calculated Gini coefficients of five different expressway sections on AADTday and Chuseok and reviewed the potential advantage of the alternative by comparing the result with those from existing measures.In the analysis, the new measure showed us reasonable and reliable results and proved its applicability of appraising travel time reliability. Keywords: Travel time, Reliability, Gini coefficient, Buffer time, Buffer index