Citation

Lee J, Chen RL. Transp. Res. Rec. 1986; 1091: 117-126.

Copyright

(Copyright © 1986, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

The entering headway is a parameter of fundamental importance to traffic engineers. It has major applications in intersection capacity and signal timing. However, the attention given to this matter appears to be inadequate. It was indicated by a literature review that past efforts tended to be infrequent, fragmented, and limited in scope. No studies were found using data from small cities or investigating factors that affect entering headways. This study, aimed at measuring entering headways in a small city and examining six factors, was conducted on sites in Lawrence, Kansas. Entering headway values from a total of 1,899 traffic queues were recorded by using video camera equipment. From the data, mean entry headways of vehicles 1 through 12 were found to be 3.80, 2.56, 2.35, 2.22, 2.16, 2.03, 1.97, 1.94, 1.94, 1.78, 1.64 and 1.76. Of the six factors studied, the following were also found: the signal type and the time of day have little influence on vehicular entering headways; vehicles in the inside lane of an intersection approach have lower entering headways than vehicles in the outside lane; vehicles in an intersection approach with lower speed limits have higher entering headways; vehicles in intersection approaches of streets with lower functional classifications have higher entering headways; and longer queue lengths appear to produce shorter entering headways for vehicles. However, because of data limitations, findings on the factors studied shall be viewed as only preliminary.

Language: en

Keywords

ROADS AND STREETS; STREET TRAFFIC CONTROL; TRAFFIC SIGNS, SIGNALS AND MARKINGS - Classification; TRAFFIC SURVEYS - Video Recording