Transportation Study - Establishing Monitoring Programs for Travel Time Reliability

The Institute for Transportation Research and Education (ITRE), in conjunction with NISS, Kittelson & Associates, Inc. (KAI), Berkeley Transportation Systems (BTS), the University of Utah, and Rensselaer Polytechnic Institute (RPI) will work on a research project, Establishing Monitoring Programs for Travel Time Reliability.

Travel time reliability refers to the fact that travel times vary. For people or goods making similar trips within a specific time period between two points, there is an underlying distribution of travel time. People making trips respond to this variation in different ways as do those involved in shipping freight. For example, important trips like doctor visits and just-in-time freight deliveries require punctuality, so the driver (or freight dispatcher) needs to build extra time into the trip to ensure a high probability of arrival within an acceptable time window, for example being early or on-time 95% of the time (or on 19 out of 20 days).

In recent years it has become increasingly apparent that urban road networks are struggling to provide the quality of service for which they were originally designed and built. Rising demand has caused increased congestion, making travel times highly variable and difficult to predict.

Operating agencies examine not only freeway travel times, through observations like spot speeds, they also monitor travel times between prevalent origin-destination (OD) pairs, including the surface street portions of the trips. To do this, they have to fuse data from arterial network sensors and traffic control devices with freeway data to estimate not only average OD travel times but the 95th percentiles of those times.

This study will answer some questions such as what are the most effective ways to instrument highway networks to obtain this information? What are the best ways to fuse the data, depending upon what is available? What are the best possible estimates of the travel times?