Travel time variability has recently become an important measure in transportation system management and it has begun to be treated as a major factor influencing travel decision. The main purpose of this study is to develop a database in order to help understand traffic variability of point measures and route-level measures by incorporating existing traffic surveillance systems. This study develops an integrated Geographic Information System (GIS) database for traffic analysis in Orange County, California, and it reports temporal and spatial traffic variability as measures of travel reliability. The database is to provide the analysis framework to study the travel time variability in both section-level as well as route-level. In many cases, traffic data are just used for traffic operations without storing the data. The archived traffic data can play an important role as a way of measuring freeway performance. Such historic data enable us to analyze such travel time variability from a long-term perspective. The database developed in this study is expected to help researchers and practitioners understand travel time variability as a measure of transportation system reliability by providing the analysis framework.
Abstract