Field Test of Nonintrusive Traffic Detection Technologies

Abstract

The results of a 2-year field test of nonintrusive traffic detection technologies are presented. Seventeen devices representing the following eight technologies were evaluated: passive infrared, active infrared, magnetic, radar, doppler microwave, pulse ultrasonic, passive acoustic, and video. The devices were tested in a variety of environmental and traffic conditions at both intersection and freeway test sites. Emphasis was placed on urban traffic conditions, such as heavy congestion; locations that typify temporary counting situations, such as 48-hour or peak hour counts; and performance in the wide variety of weather conditions found in Minnesota. The evaluation also focused on the ease of system set-up and general system reliability. The results show that nonintrusive technologies are capable of performing as well as conventional methods in some, but not all, situations. At the freeway test site, most nonintrusive devices counted within 3 percent of baseline data. At the intersection test site, however, congested stop-and-go traffic hindered the performance of the majority of the devices. Weather and other environmental variables were found to have minimal impact on the majority of devices. This test is the first phase of an ongoing project to evaluate new, nonintrusive technologies and devices. Further research will expand into areas such as real-time datacollection to support intelligent transportation system applications.