Remote Sensing Devices

How it works

  • • The vehicle first passes through (3) speed and acceleration detectors, while an (5) image of the license plate is taken to ensure the vehicle tag matches the registration record.

  • • The vehicle then passes through safe, low intensity infrared and ultraviolet beams of the (2) emissions analyzer. A safe 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 and particulate matter in the exhaust. (4) The emissions readings are matched to the license plate and an official test record is created and compiled for RSD Data Applications.


  • To ensure accurate, uncontaminated readings, RSD’s do not operate during rain, snow, high winds or other adverse weather conditions.

RSD Data Applications

How it works

RSDs allow for the measurement of:

  • the effectiveness of I/M programs.
  • the evaluation of entire fleets in geographic areas comparing emissions of vehicles from I/M and non-I/M areas.
  • the impact vehicles registered outside of a testing region (e.g. commuters or tourists) have on air quality within a program area.
RSD data can be used to:
  • compare computer models to real-world data.
  • cost-effectively characterize entire fleets.
  • provide comparison data from I/M and non-I/M areas.
  • provide emissions by county and identify out-of-area commuters.