Development of a Travel-Time Reliability Measurement System

This study has developed a computerized Travel-Time Reliability Measurement System (TTRMS), which can automate the time-consuming process of gathering and managing data from multiple sources and calculating various types of reliability measures under user-specified conditions for given corridors. The TTRMS adopts a server and client structure, where the main database and computational engines reside in the server, while the user-clients are designed for entering the data and generating the output files. In particular, most of the external data, such as traffic and weather datasets, can be remotely downloaded following predefined time schedules. Further, the travel-time calculation process developed in this study can explicitly reflect various lane-configurations at work zones for correctly calculating travel times of the routes with work zones. The map-based user interfaces provide users with a flexible environment, where the route selection and specification of operating conditions for reliability estimation can be efficiently performed. The integrated TTRMS was tested in the Twin Cities’ metro freeway network by estimating the reliability measures of selected corridors with real data for a two-year period, 2012-13. The test results indicate that the TTRMS can substantially reduce the time and effort in estimating various types of reliability measures under different operating conditions for predefined corridors.