Peterson, Scott

While most vehicle classification currently conducted in the United States is axle-based, some applications could be supplemented or replaced by length-based data. Common length-based methods are more widespread and can be less expensive, including loop detectors and several types of non-loop sensors (both sidefire and in-road sensors). Loop detectors are the most frequently deployed detection system and most dual-loop installations have the capability of reporting vehicle lengths. This report analyzes various length-based vehicle classification schemes using geographically diverse data sets. This report also conducted field and laboratory tests of loop and non-loop sensors for their performance in determining vehicle length and vehicle speed. The study recommends a four bin length scheme with a fifth bin to be considered in areas with significant numbers of long combination vehicles. The field and laboratory testing found that across a variety of detection technologies, the sensors generally reported comparable length and speed data.

This phase of the project focused on conducting field tests of selected non-intrustive sensors to determine their accuracy for volume, speed and classification by length and classification by axle configuration. The project also identified deployment issues and costs associated with the technologies.

The Aurora Consortium is a joint program of collaborative research, evaluation and deployment of advanced technologies for detailed road weather monitoring and forecasting. Members seek to implement advanced road and weather information systems that fully integrate state-of-the-art roadway and weather forecasting technologies. Many agencies use various models of in-ground and mobile sensors to measure pavement temperature. However, little documentation exists on the accuracy of the various sensors, and there is no standard methodology for sensor testing. The data and conclusions drawn from this study are published so that Aurora members and others will have additional information to assist in their implementation and procurement decisions. Additionally, results from this study will be used by the NCHRP to develop testing and calibration standards for pavement sensors. The objective of this project was to conduct both laboratory and field studies of various competing models of in-pavement (contact) and mobile (non-contact) type pavement temperature sensors and compare them to baseline readings in order to quantify the surface temperature measurement performance of each sensor and sensor type. The laboratory tests were conducted at the Braun Intertec laboratory in Bloomington, Minnesota. Field tests were conducted at the Minnesota Department of Transportation's (Mn/DOT's) Mn/ROAD facility near Monticello, Minnesota.