This paper describes results of an updated methodology for conducting travel time studies on signalized highways. The methodology is based on the use of global positioning system (GPS) and geographic information system (GIS) technology. GPS receivers log the position and velocity of a probe vehicle every one second. The data reduction procedures filter and aggregate GPS data to compute travel times and speed values on all highway segments along the paths studied. For analysis purposes, segment lengths ranging from 0.1 mi to 5 mi (0.16 km to 8 km) are used. The corresponding aggregated travel time and speed values are then compared to those of the original GPS data. The data reporting procedure uses a GIS-based management information system to define queries, tabular reports, and color coded maps documenting travel time data along the corridor segments. Examples of the data that can be derived include travel times, average speeds, minimum speeds, and delays. Alternative reporting procedures using World Wide Web (WWW) resources are also described. (A)
Samenvatting