Practical Procedure to Collect Arterial Travel Time Data Using GPS-Instrumented Test Vehicles

Abstract

Arterial streets are interrupted flow facilities that balance two purposes: serving through trips and providing commercial and residential access to adjacent land. A dominant factor in urban arterial street operations is the presence of traffic signals, which govern the flow of vehicles entering and exiting an arterial segment. Consequently, the performance of an arterial street is predominately influenced by delays incurred at traffic signals, with measures of effectiveness primarily a function of the performance at the arterial segment level. This paper presents a practical procedure to collect and analyze travel time data, based on Global Positioning Systems (GPS), that readily reflect measures of performance for both segments and extended arterial sections. Underlying this procedure is an assumption that both average travel speed and average intersection approach delay can be calculated as a function of arterial segment travel time, resulting in travel time as a primary field measurement used for gauging arterial performance. Procedures developed include both field data collection techniques that center on GPS technologies and algorithms for processing the gathered GPS-based travel time data.