Commercial vehicle traffic is at an all-time high on America's highways, comprising over 30% of all interstate highway vehicle traffic. Each year there are hundreds of thousands of accidents that involve commercial trucks and the related number of deaths runs in the thousands annually. A significant portion of these truck accidents list faulty brakes as a contributing factor, so break inspection has become an important part of traffic safety enforcement policies around the US.

The Washington State Department of Transportation's (WSDOT) has therefore installed an Automated Infrared Roadside Screening (AIRS) system that utilizes a FLIR A315 thermal imaging camera to automatically detect defective breaks in trucks at several weighing stations.

Automatically Detect Malfunctioning Brakes

Thermal imaging cameras like the A315 detect and display differences in temperatures by detecting the intensity of thermal radiation. The FLIR A315 thermal imaging camera can accurately measure the temperature of millions of separate points and export all of that thermal data to a computer for precise analysis.

The FLIR A315 thermal imaging camera used for the AIRS system is installed in a protective enclosure and mounted in the entrance of a commercial vehicle weighing station. The camera provides detailed thermal images of the undercarriage of commercial vehicles as they enter the station. "AIRS automatically scans and assesses the underside of commercial vehicles for conditions such as malfunctioning brakes, overheated bearings and tire risks," project manager Victor Bagnall explains.

Once the vehicle has passed the camera, the AIRS computer analyzes the captured data and compares the signal patterns with the system's predefined conditions. The computer creates a record of the vehicle, including all of the relevant temperature data and the thermal image of the vehicle. This record is displayed on the AIRS screen, alongside the records of other vehicles that come into the station before and after it. Records are deleted from the system once the truck leaves the station. Defective brakes are typically colder than a vehicle's operational brakes. This difference is clearly visible on a thermal image. This enables the AIRS system to detect these defective breaks automatically.