Calculation of Travel Time Variability from Loop Detector Data

Abstract

Travel time variability has recently become an important measure in transportation system management and has begun to be treated as a major factor influencing travel decisions. The main purpose of this study is to develop a database 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 database for traffic analysis in Orange County, California, and reports temporal and spatial traffic variability as measures of travel reliability. The database is to provide the analysis framework to study travel time variability at both the section level and the route level. In many cases, traffic data are used for traffic operations without the data being stored. The archived traffic data can play an important role as a way of measuring freeway performance. Such historic data make it possible 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.

Get full access to this article

View all access options for this article.

References

Bates

Dix

and May

Travel Time Variability and Its Effect on Time of Day Choice for the Journey to Work, Transportation Planning Methods. Proc., Seminar C, PTRC, 1989, pp. 293–311.

Small

K. A.

Noland

Chu

and Lewis

NCHRP Report 431: Valuation of Travel-Time Savings and Predictability in Congested Conditions for Highway User-Cost Estimation. TRB, National Research Council, Washington, D.C., 1999.

Abdel-Aty

M. A.

Kitamura

and Jovanis

P. P.

Investigation Effect of Travel Time Variability on Route Choice Using Repeated Measurement Stated Preference Data. In Transportation Research Record 1493, TRB, National Research Council, Washington, D.C., 1995, pp. 39–45.

Lam

and Small

The Value of Time Reliability: Measurement from a Value Pricing Experiment. Transportation Research E, Vol. 37, 2001, pp. 231–251.

Levinson

and Zhang

Travel Time Variability After a Shock: The Case of the Twin Cities Ramp Meter Shut Off. Presented at First International Symposium on Transportation Network Reliability, Kyoto, Japan, July 30–Aug. 1, 2001.

Richardson

A. J.

Travel Time Variability on an Urban Freeway. Urban Transport Institute (TUTI) Report 25-2003. Urban Transport Institute, Victoria, Australia, 2003.

Lomax

Turner

and Margoitta

Monitoring Urban Roadways in 2001: Examining Reliability and Mobility with Archived Data. FHWA-OP-03-141. Texas Transportation Institute and Cambridge Systematics, Inc., 2003.

Lomax

Schrank

Turner

and Margoitta

Selecting Travel Time Reliability Measures. Texas Transportation Institute and Cambridge Systematics, Inc., 2003.

Chen

Skabardonis

and Varaiya

Travel-Time Reliability as a Measure of Service. In Transportation Research Record: Journal of the Transportation Research Board, No. 1855, Transportation Research Board of the National Academies, Washington, D.C., 2003, pp. 74–79.

10.

Hall

F. L.

and Persaud

B. N.

Evaluation of Speed Estimates Made with Single-Detector Data from Freeway Traffic Management Systems. In Transportation Research Record 1232, TRB, National Research Council, Washington, D.C., 1989, pp. 9–16.

11.

Jia

Chen

Coifman

and Variaya

The PeMS Algorithms for Accurate, Real-Time Estimates of g-Factors and Speeds from Single-Loop Detectors. IEEE Intelligent Transportation Systems Conference Proceedings, Oakland, Calif., Aug. 25–29, 2001, pp. 536–541.

12.

Wang

and Nihan

Can Single-Loop Detectors Do the Work of Dual-Loop Detectors?

Journal of Transportation Engineering, Vol. 129, 2003, pp. 169–176.

13.

Kim

J. S.

and Jayakrishnan

Effect of Taxi Information System on Efficiency and Quality of Taxi Services. In Transportation Research Record: Journal of the Transportation Research Board, No. 1903, Transportation Research Board of the National Academies, Washington, D.C., 2005, pp. 96–104.