Assessment of Transportation System Reliability at Link-, Corridor- and Area-level

There has been a paradigm shift in focus from intersection-level to corridor-and area-level analysis and performance measures in recent years. The possibility of capturing dynamic and continuous travel time and/or speed data from private sources such as INRIX opens many pragmatic avenues to predict reliability of transportation systems. Travel time reliability (or index or variability) is considered the most viable performance measure for corridor-level analysis though it is not being widely used for transportation planning, project prioritization, and allocation of resources. The definition of reliability as a performance measure and associated thresholds to understand or assess transportation system performance could vary for a link, corridor or an area. These definitions and thresholds to assess reliability need to be clearly established prior to its large scale application. This research aims to fill this gap by computing, comparing, and assessing link-, corridor- and area-level reliability measures. Data for the city of Charlotte, North Carolina was used to compute reliability measures, examine temporal and spatial variations, and illustrate how reliability can be used for transportation planning, prioritization and allocation of resources.