Vehicles registered in the five-parish area around Baton Rouge consisting of Ascension, East Baton Rouge, Iberville, Livingston, and West Baton Rouge parishes are subject to emissions testing during an annual combined safety/emissions inspection.
Diesel Vehicles:
Diesel vehicles are not tested for emissions.
Exemptions:
1. New vehicles for the newest two (2) model years
2. Pre-1980 model year vehicles
3. Vehicles with a GVWR of more than 10,000 lbs
For more information visit: https://deq.louisiana.gov/
Louisiana Revised Statutes
§ 32:352. Mufflers; requirements; prevention of excessive noise, fumes and smoke
A. Every motor vehicle shall at all times be equipped with a muffler in good working order and in constant operation to prevent excessive or unusual noise.
B. No person shall use a muffler cut-out, bypass or similar device upon a motor vehicle on a highway of this state.
C. The engine and power mechanism of every motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.
§ 32:353. Modification of exhaust systems
No person shall modify the exhaust system of a motor vehicle in a manner which will amplify or increase the noise emitted by the motor of such vehicle, above that emitted by the muffler originally installed on the vehicle and the original muffler shall comply with all of the requirements of R.S. 32:352.

Antique
Available for vehicles that are at least 25 years old that have been restored to their original condition without modifications.

Military Vehicle
Military honor license plates are available for motorized and nonmotorized World War II or Korean War military vehicles, including motorcycles and trailers. Military honor license plates are available for other motorized and nonmotorized military vehicles, including motorcycles and trailers, which can be classified as vehicles of historic or special interest and which are owned by collectors.

Street Cruiser
Available for vehicles that are at least 25 years old and have undergone some type of modernizing, including modernization of the engine, transmission, drive train, interior refinements, and any other modifications the builder desires, which must be driven to events under their own power and used as safe non-racing vehicles for total family enjoyment.

Street Rod
Available for any antique automobile or truck produced in 1948 or earlier, which is an automobile or truck that is recognized as a street rod by the National Street Rod Association, and which has undergone some type of modernizing, to include modernizing of engine, transmission, drivetrain, interior refinements, and any other modifications the builder desires, which vehicle is to be driven to events under its own power and to be used as a safe, nonracing vehicle for total family enjoyment.

YOM
Vehicles registered as "Antique" may display YOM plates with DMV approval.