Quantifying Operational Disruptions as Measured by Transportation Network Reliability

Abstract

There is global interest by transportation planners and enterprise operators to monitor the inherent uncertainty of transportation networks. Traditional performance metrics may erroneously prioritize project initiatives based on disruptions measured from ideal driving speeds; however, commuters and enterprise operators have demonstrated the ability to accommodate recurrent highway congestion by adjusting departure times, transportation modes, origins, or destinations in logistics planning. Recent performance metrics of transportation network reliability have demonstrated the importance of measuring disruptions from normal operating conditions. Using disaggregate speed data, typical conditions are assessed by mean and median speeds across disparate hours of the day and days of the week. In this paper, we establish a quantitative multicriteria framework for measuring operational disruptions based on the intensity and duration of observed deviations from normal conditions. Advances in data collection provide the disaggregated data that can be used to identify when disruptions occur and the extent of affected volume. This approach influences the prioritization of infrastructure improvements based on deviations from typical conditions and informs appropriate mitigation strategies based on the category and time of disruption. A demonstration of the approach to a geographically diverse region is provided, with implications for several agency-planning horizons.