Furthermore, studies suggest that repairs significantly reduce emissions only for cars with high emissions. Repairs made to cars that are only marginally over their emissions standards do little to reduce emissions and often even increase them. Because of the extreme variation of emissions, and because most emissions reductions will come from the gross polluters, the chief task of a cost-effective program must be to focus on gross polluters. Remote sensors appear to be capable of doing just that. The sensor receiving the distorted beam can infer the pollutant concentrations in the exhaust.
Remote sensors are inexpensive and mobile and can be set on many streets and highway ramps.
As the infrared beam passes through the exhaust plume, a camera automatically snaps a picture of the license plate. If government can use remote sensors to identify gross polluters, it can clean the air at low cost to the public. Regulators are beginning to show interest in remote sensing, but they have not yet recognized the full potential of the new technology. If remote sensing lives up to its promises, the best way to control auto emissions is a remote-sensing program that punishes persistent high emitters with monetary fines. The program simply polices the airshed, which is common property.