Long-Term Research into Vehicle Detector Technologies

Project Description

Many transportation applications require the use of systems that can detect vehicle presence and traffic flow. Detector systems have traditionally used inductive loops, but loop systems have well-documented concerns. Combined with the increasing availability of newer detectors, these concerns prompted Texas Transportation Institute (TTI) researchers to investigate the performance aspects of newer detectors.

Determining appropriate loop-replacement strategies required investigating accuracy and reliability of new detection technologies along with the means of interfacing new detector systems with the Texas Department of Transportation's (TxDOT's) existing components. Therefore, TTI researchers conducted field tests of detectors and investigated interfacing options with the TxDOT Advanced Traffic Management System (ATMS).

This research found that microwave radar, magnetometers, and some video image vehicle detection systems (VIVDSs) are suitable for freeway applications:

• Of the technologies studied, VIVDSs offer the best view of the traffic stream but are more complex, require periodic lens cleaning, and are usually more expensive. Even the latest VIVDS technology appears to remain affected slightly by some weather and lighting conditions.
• Magnetometer technology warrants continued evaluation over a longer period of time. Its accuracy levels are noteworthy and it is not affected by weather, but battery life might be an issue under some conditions with one of the available products.
• The microwave radar device investigated in this project proved to be a rugged auto-configuring device that can be installed and maintained without interfering with traffic, can be mounted on an existing pole, can cover up to eight lanes in sidefire orientation, and is apparently not affected by weather or lighting conditions.

Each technology has unique advantages and disadvantages, but all were shown to be applicable to freeway traffic management needs.

Project Publications

Investigation of Vehicle Detector Performance and ATMS Interface 0-4750-2

Long-Term Research into Vehicle Detector Technologies 0-4750-S

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