MODELING TRAVEL TIMES ALONG SIGNALIZED STREETS USING EXPECTED CUMULATIVE COUNTS. IN: URBAN AND REGIONAL TRANSPORTATION MODELING. ESSAYS IN HONOR OF DAVID BOYCE

Abstract

Highway traffic can be conveniently represented with cumulative counts. Expected cumulative counts can be used to more accurately predict travel times. This chapter on modeling travel times along signalized streets is from a book of essays published in honor of David Boyce for his contributions to the fields of transportation modeling and regional science. In this chapter, the authors consider the use of expected cumulative counts for estimating and predicting vehicle travel times between two points, with the application to signalized intersections. The authors discuss how to estimate expected travel times of vehicles with known preferred speeds; the concept of FIFO (first in, first out) traffic; L curves and their use for non-conserved traffic and for signalized streets; and selected field data that demonstrates the use of expected cumulative counts, including congestion level, the type of signal controller, road segment length, signal progression, and traffic entering and exiting between intersections. The authors use three actual case studies to compare the predicted expected travel times to the measured travel times of individual vehicles. The results indicate that cumulative L curves should be considered as a feasible approach to modeling travel times along signalized streets for a wide range of traffic conditions.