Faulty Loop Data Analysis/correction and Loop Fault Detection

Inductive Loops are widely used in California for traffic detection and monitoring. Extensive studies have been conducted to improve loop detection system performance. This paper reviews previous work on faulty loop data analysis for correction and faulty loop diagnosis. It is necessary to distinguish faulty loop data analysis and loop fault detection according to the data level. According to the level of data used, it divides the work in three levels: (1) macroscopic level as in TMC (Transportation Management Center) or PeMS (Performance Measurement System) in California, which uses highly aggregated data to look at loop problems related wide range; (2) mesoscopic level, which involves synchronized data for a section of freeways involving several control cabinet such as Berkeley Highway Lab (BHL); and (3) microscopic level: or at a control cabinet level including all the loop stations involved. Corresponding data correction methods are also briefly reviewed.