This report documents the development of data collection methodologies that can be used to cost effectively measure truck movements along specific roadway corridors selected by transportation agencies in Washington State. The intent of this study was to design and test methodologies that could be used to measure the performance of freight mobility roadway improvement projects against benchmarks, or selected standards, that would be used both as part of the project selection process and to report on speed and volume improvements that resulted from completed freight mobility projects.
One technology tested was Commercial Vehicle Information System and Networks (CVISN) electronic truck transponders, which are mounted on the windshields of approximately 20,000 trucks in Washington. By using software to link the transponder reads from sites anywhere in the state, the transponder-equipped trucks could become a travel-time probe fleet. The second technology tested involved global positioning systems (GPS) placed in volunteer trucks to collect specific truck movement data at 5-second intervals. With GPS data it was possible to understand when and where the monitored trucks experienced congestion and to generate useful performance statistics.
The study found that both data collection technologies could be useful; however, the key to both technologies is whether enough instrumented vehicles pass over the roadways for which data are required. This basic condition affects whether the technologies will be effective at collecting the data required for any given benchmark project. The report also recommends the traffic data that should be collected for a benchmark program and the potential costs of using either data collection technology.