Book Description

This report presents both survey results and field data analysis investigating information needs for motor carrier logistics. Relevant research in the area of estimating travel time characteristics is presented. Survey results of trucking companies and trucking professionals are also included. Although the sample size is low, useful insight obtained from the respondents is discussed. The accurate estimation of travel time data is valuable for a variety of real-time and off-line transportation applications including motor carriers. This report includes methodologies for estimating corridor travel time mean and variance from field data collection at two test sites. The test sites are two limited-access freeway corridors: one instrumented with automatic vehicle identification (AVI) antennas and one instrumented with dual inductance loop detectors at 0.5 mile spacings. The estimates using the intelligent transportation system (ITS) data were compared to simultaneous instrumented test vehicle and commercial vehicle travel time data. A procedure was outlined for using the loess nonparametric statistical technique to obtain corridor travel time mean and variance estimates from each ITS data source, commercial vehicles and instrumented test vehicles. The estimates from each data source were then aggregated to five minutes, and the ITS data source estimates were compared to the commercial vehicle and instrumented test vehicle corridor travel time estimates. A methodology for testing the accuracy of instrumented test vehicle drivers along a corridor was also developed. The research demonstrates that commercial vehicles have statistically different travel time mean and standard deviation than AVI-equipped vehicles, which suggests it may be beneficial to provide traveler information in real-time for commercial vehicles. It was also found that AVI-equipped vehicles were not statistically different than the instrumented test vehicles and that an AVI system with an adequate number of tag reads could replace traditional data collection methods. By comparing inductance loop travel time estimates to the commercial vehicle and test vehicle data sources, the research quantifies how aggregated inductance loop detector travel time estimates do not capture the travel time variance characteristics of individual vehicles.