Accurate estimation of travel time is necessary for monitoring the performance of the
transportation system. Often, travel times are estimated indirectly by using instantaneous
speeds from inductance loop detectors and making a number of assumptions. Although
these travel times may be acceptable estimates for uncongested conditions, they may have
significant error during congested periods. Travel times also may be obtained directly from
intelligent transportation systems (ITS) data sources such as automatic vehicle identification …

Instrumented test vehicle runs are often performed to obtain travel time estimates for system
monitoring and other transportation applications. Distance-measuring instruments (DMI) are
a common method of instrumentation for test vehicles. This paper compares DMI travel time
estimates with AVI travel time estimates using a variety of statistical approaches. The results
indicate that the travel time estimates from test vehicles instrumented with DMI are within
one percent of travel time estimates from AVI along the study corridor. These results reflect …