Field Test Of Monitoring Of Urban Vehicle Operations Using Non Intrusive Technologies PDF Download

The use of non-intrusive technologies for traffic detection has become a widespread alternative to conventional roadway-based detection methods. Many sensors are new to the market or represent a substantial change from earlier versions of the product. This pooled fund study conducted field tests of the latest generation of non-intrusive traffic sensors. Sensors were evaluated in a variety of traffic and environmental conditions at two freeway test sites, with additional tests performed at both signalized and unsignalized intersections. Emphasis was placed on urban traffic conditions, such as heavy congestion, and varying weather conditions. Standardized testing criteria were followed so that the results from this project can be directly compared to results obtained by other transportation agencies. While previous tests have evaluated sensors' volume and speed accuracy, the current generation of sensors has introduced robust classification capabilities, including both length-based and axle-based classification methods. New technologies, such as axle detection sensors, and improved radar, contribute to this improved performance. Overall, the sensors performed better than their counterparts in previous phases of testing for volume and speed accuracy. However, the additional classification capabilities had mixed results. The length-based sensors were generally able to report accurate vehicle lengths. The axle-based sensors provided accurate inter-axle measurements, but significant errors were found due to erroneously grouping vehicles, affecting their ability to accurately classify trucks.