How It Works
RapidScreen testing vans set up at highway on-ramps and other locations where vehicles are accelerating or driving uphill at a moderate speed, because these conditions generate the most representative sample of a vehicle’s exhaust emissions.
As a vehicle passes by, the roadside testing equipment is able to analyze the vehicle’s exhaust in less than a second. Here’s how RapidScreen works:
The vehicle first passes through (3) speed and acceleration detectors, while an (5) image of the license plate is recorded for identification.
The vehicle then passes through the infrared and ultraviolet beams of the (2) emissions analyzer. A laser light source directs the beams across the road, where they are bounced off (1) mirrors and directed back to a detector module. As the light beams are broken by the vehicle’s exhaust plume, the detector module measures the levels of carbon monoxide, carbon dioxide, hydrocarbons and oxides of nitrogen in the plume. (4)The emissions readings are matched to the license plate and an official test record is created.
To ensure accurate, uncontaminated readings, RapidScreen testing vans do not operate during rain, snow, high winds or other adverse weather conditions. RapidScreen also holds to stricter emissions limits than those of a standard tailpipe emissions test.