Do semi-trucks need to be smog checked?

Question

It seems like one puff of their cloud of smoke would be more than a week of a regular car that might not pass smog..

Answer 1

In California, at least, semi trucks don't under go the standard California smog check inspection as do passenger vehicles. They do however need to pass an annual and/or random "smoke test". The smoke test determines, based on the color and density of the exhaust, whether the semi is polluting or not.

The fines are hefty, and most truck operators are very careful to make sure their semi's don't smoke. Every so often you pass by one that does pollute, but be assured, first glance of a CHP Officer and that vehicle is pulled over and sent for official inspection and possible fines.

Random inspections are performed at semi weight stations which are located through out the state near freeway off ramps. During a semi's weighting, a CHP Officer will randomly or as seen necessary, ask the driver to move the vehicle into a special facility on site and administer the smoke test. If the semi fails, it is fined right away. Fines usually range $1000.00 or more.

Hope this information is helpful.

Answer 2

Diesel smoke contains lots of carbon, but very little of the chemicals that are prime contributors to smog. Therefore, diesels are exempt from smog checks in most jurisdictions.

Answer 3

In most states diesels do not get smog checked. Although they emit more vi sable pollutants they emit less invisible pollutants.A properly adjusted diesel is cleaner burning than most gasoline engines and considerably more efficient( diesel is 25% efficient at obtaining energy from burning the fuel, gasoline engines are 12 1/2 %) and produces nearly twice the mileage per gallon.

Answer 4

in N.J. they spot check diesels at the scales for smog

Answer 5

They are exempt, at least in my state... So are diesel powered pick-ups and cars...