The objective of this project is to develop an inductive loop-based technology for monitoring the travel time and origin-destination performance of vehicles that augments a Bluetooth-based travel time system now under development. To their advantage, loop signatures characterize almost 100 percent of the vehicles traveling over them while Bluetooth technology characterizes none of them. Bluetooth always correctly reidentifies vehicles while loops may mismatch or miss signature matches. Research findings during phase I of this project have led the research team to conclude that it is feasible to use 60 Hertz (Hz) samples from single loop detectors in order to perform reidentification between loop detector stations on freeways. The method employed was robust to loop calibration errors, easily corrects for metadata concerning the exact location of the loops, and demonstrated that it was possible to reidentify vehicles up to 1.5 miles away (which was the extent of our test section). This project proposes to productize this research by implementing the software in the commercial archive data management systems, PeMS. We will then perform large field tests of this methodology in both a congested, urban area as well as in a rural area in order to demonstrate its effectiveness over a variety of conditions. These tests will be done on live freeways with the support of California Department of Transportation (Caltrans).
This phase I project was successful and established the possibility of obtaining travel time data using high-frequency conventional loop data. A phase II followup project was recommended. May 12, 2014. The project successfully demonstrated that it was possible to collect travel time data similar to Bluetooth data using existing loop detectors and modified signal controller software. The project reports are being reviewed to determine if a Phase IIb commercialization project should be recommended.