How RSD Works

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AccuScanâ„¢ remotely measures exhaust emissions from motor vehicles as they are driven past the remote sensing device on streets and highways. Measurements are recorded in a computer database without the vehicle ever coming to a stop or even slowing down.

Emissions are measured by casting a narrow infrared (IR) and ultraviolet (UV) beam of light across the road. A transfer mirror module then reflects IR/UV light back to a series of detectors that monitor light intensity at characteristic wavelengths. By measuring the absorption of IR/UV light by the various pollutants in the air, the system is able to calculate the pollutant concentrations in the vehicle exhaust plume.

While emissions are measured, a video camera system captures an image of the vehicle's license plate. Meanwhile, speed/acceleration sensors record the speed and acceleration of each vehicle. Emissions and related data are stored in a computer for reporting and analysis. The entire process is accomplished in a fraction of a second.