[Jim Sims]

"As a practical matter, it is." Heard of photo radar; here comes photo smog test:

What is a gross polluter?
Vehicles that fail by a wide margin are considered "gross polluters." (10 percent of vehicles produce about half the auto-related emissions — or 12 percent of emissions from all sources.) A gross polluter can be any age or type of vehicle that has been tampered with, poorly maintained or in need of repair. It is illegal to drive or sell a gross polluting vehicle in California, and it cannot be registered with the DMV.

There is no cost limit on repairs to these vehicles. If they are repaired to below gross polluter threshold, they are eligible for a one-time waiver or "economic hardship extension." After the waiver period, the car must be brought in to compliance or disposed of in a proper manner. Gross-polluting vehicles are not subject to confiscation by the state.

Why am I seeing roadside emission sensors?
The state will use roadside sensors to help in the identification of gross polluters. The program is not yet fully operational. The equipment motorists are now seeing in Southern California is gathering information on locations and set up. When the plan is implemented, owners of vehicles identified as gross polluters by a roadside sensor will be mailed a notice and must have the car tested at a designated test-only station. If it passes, the owner will not need to take any further action. If the car fails, the procedures are the same as those described above, depending on how badly the vehicle fails. Failure to respond to the notice will result in fines.

Additional changes compared to the old smog check program:

Pre-1976 vehicles have been exempted from biennial smog checks as well as smog checks upon transfer of title. The 1966 to 1975 vehicles are still subject to smog checks if they are identified as "dirty" by a roadside sensor or audit.
New cars under five years old receive the same exemptions as pre-1976 cars. Gross polluters must go to a designated station for a retest after repairs have been made.
Smog check test information is electronically transmitted by the technician directly to the state. Vehicle owners will no longer submit certificates to the DMV at vehicle registration time. Motorists should take their registration renewal form to the test site to assure the accuracy of the information transmitted.
Smog check technicians and mechanics are subject to improved training, testing and monitoring by the state.
Where can I get more information?
The Bureau of Automotive Repair has an information line — (800) 952-5210.