Travel Time Estimation on Urban Arterials Using Loop Detector Data

H. Michael Zhang
Eil Kwon
1997

Travel time is an important parameter for evaluating the operating efficiency of traffic networks, assessing the performance of traffic management strategies, and developing real-time vehicle route guidance systems. The envisioned operational tests of Advanced Traveler Information Systems (ATIS) and Advanced Traffic Management Systems (ATMS) in the Minneapolis/St. Paul area call for a provision of timely and reliable travel times over an entire road network. Travel times can be obtained in a number of ways. They can be measured directly using probing vehicles or advanced detection technologies (e.g., AVI, AVL, and video image processing), or estimated indirectly from traffic data provided by conventional detection technologies such as inductive loop detectors. Directly measuring travel time is usually costly and often requires new types of sensors. A more cost-effective way of obtaining travel time is to estimate it using traffic data, particularly those provided by loop detectors that are already in place in most signalized arterials and freeways.

There are reliable methods for estimating travel time on freeways using loop detector data. The interrupted nature of traffic flow on arterial routes and numerous other factors that affect travel times on arterial links, however, make the estimation of travel times on arterials a much more challenging task. There have been attempts to utilize loop detector data (particularly occupancy) and signal timing parameters to estimate arterial link travel times. Despite the various degrees of success achieved in these studies, few of the models developed to date have been applied to real world situations. The reasons for this are largely twofold: 1) some of the models require traffic data that are not or cannot be routinely collected from loop detectors (such as the arrival time of a vehicle at a detector), and 2) some of the models were site-specific and cannot be applied to other locations without recalibration.

In recognition of the need for an effective yet inexpensive way of estimating arterial travel times, the Minnesota Department of Transportation has sponsored a research project to develop a travel time estimation model using loop detector data. This two-phase project is being jointly conducted by researchers from the University of Iowa and the University of Minnesota. Phase I involves a literature review, traffic data collection and development of a travel time database; Phase II covers model development, calibration and evaluation. This report summarizes the findings of Phase I.

$12.95, 77 pp., 9 figures, saddle stitched
ISBN 0-87414-141-9
This publication is no longer in print.