Evaluation of Dual-Loop Data Accuracy Using Video Ground Truth and Data.

摘要

If sufficiently accurate, dual-loop detectors can be very cost-effective collectors of real-time vehicle-classification and speed data. This report describes a Washington State Department of Transportation (WSDOT)/TransNow-funded study that addresses the problems with the existing detection system encountered by the original freight study, and recommends remedial actions to rectify these problems. The researchers (1) investigated the level of inaccuracies in the existing WSDOT dual-loop freeway detectors, (2) identified the types and potential causes of these inaccuracies, and (3) proposed methods to effectively improve the quality of the dual-loop data. The objectives of the project were to (1) identify a station of good dual-loop detectors to represent the WSDOT system, (2) quantitatively analyze the data collected from the selected station and determine the accuracy of the sample dual-loop measurements for vehicle volumes and vehicle classifications, (3) identify the types and potential causes of the observed inaccuracies, and (4) recommend appropriate methods to improve overall dual-loop data quality.