A METHODOLOGY FOR TRAVEL TIME RELIABILITY BENEFIT MEASUREMENT CONSIDERING TRAVEL TIME VARIABILITY

While travel time reliability benefit is a direct benefit in the cost-benefit analysis of transportation, the previous procedure for assessing the investment impact on transport facilities could not capture the reliability effect of the road investment in Korea. This paper suggests a quantitative method of reliability and reliability benefit measurement for inclusion in benefit items. The quantitative method of travel time reliability is provided to forecast travel time variability by considering specific statistics such as the free flow travel time, average travel time (ATT), standard deviation of travel time, and coefficient variation. This study measures travel time reliability benefit through case studies using actual analyzed road networks and describes the relationship between travel time savings benefit and travel time reliability benefit to demonstrate the possibility of applying it to cost-benefit analysis. The results provide strong evidence that travel time reliability benefit is an important factor for consideration in improving the travelers' convenience because the reduced travel time variation caused by a proposed road investment allows them to optimize their time and reduce their buffer time requirement. The study results are expected to improve the proposed transportation investments and policies..