For Vehicles Registered in Maryland (Maryland Registered Vehicles)

If a Maryland registered diesel vehicle fails a smoke opacity test, the registered owner of that vehicle will be issued a Safety Equipment Repair Order (SERO). The SERO is actually given to the driver of the vehicle at the time of inspection and it is the driver's responsibility to pass the SERO along to the registered owner.

The SERO is similar to other SERO's issued for safety violations, but this SERO is only issued for diesel emissions violations. On the SERO you will see a space where the emissions test readings are written. The initial reading will be recorded at the time of the initial failed smoke opacity test given by the Maryland State Police. The post repair opacity is to be filled in by the person that certifies the SERO (either a Certified Diesel Emissions Retester (CDER) or one of the Maryland State Police Emissions Inspectors). The SERO requires the owner to have the vehicle repaired as necessary and retested to show compliance with the applicable smoke opacity standard. Once the vehicle has passed a retest and the post repair opacity is written on the SERO, the blue copy (Compliance Copy #4) of the SERO is to be mailed back to the Maryland Department of the Environment at the address as follows:

Maryland Department of the Environment - ARMA
Mobile Sources Control Program
1800 Washington Blvd.
Baltimore, MD 21230

It is the responsibility of whoever certifies the SERO to return this blue copy to the Maryland Department of the Environment within 30 days of the issuance of the SERO. This means that the vehicle must be repaired and retested prior to this 30 days.

Also within 30 days of issuance of a SERO, you must return the State Police Compliance Copy No. 6 of the SERO, which contains a signature of certification to:

Maryland State Police
Automotive Safety Enforcement Division
6601 Ritchie Highway
Glen Burnie, Maryland 21062

If the certified SERO is not received within 30 days of the date the SERO was issued, the registration of the vehicle will be suspended. If this vehicle has been traded, sold, repossessed, junked or otherwise disposed of submit a notarized statement and include the vehicle serial number and the date of the applicable transaction. Attach the notarized statement to the State Police compliance Copy #6 and return both to the Maryland State Police at the address above. Also include a copy of the notarized statement attached to the blue copy of the SERO and return both to the Maryland Department of the Environment at the address given above.

If the vehicle is caught operating with a suspended registration the vehicle owner is subject to receiving a fine of up to $1,000.

Vehicles Registered Outside of Maryland (Foreign Registered Vehicles)

If a foreign registered diesel vehicle fails a smoke opacity test, the registered owner will be issued a Maryland Driver/Vehicle Inspection Report (MdVIR also referred to as a "TI"). The MdVIR is actually given to the driver of the vehicle at the time of the inspection and it is the driver's responsibility to pass the MdVIR along to the registered owner.

The MdVIR requires that the registered owner must certify that the vehicle has been brought into compliance with the applicable smoke opacity standard. Owners must demonstrate that their vehicles are in compliance by signing the MdVIR and returning it to the Maryland State Police within 15 days of its issuance. Specific instructions on mailing the certified MdVIR are located on the MdVIR. If the MdVIR is more than 30 days delinquent the Department of State Police will provide notice to the Federal Highway Administration that the owner has violated State law in violation of 49 C.F.R. Section 392.2. The owner of the diesel vehicle is also subject to a fine of up to $1,000.

Smoke Opacity Standards

Vehicles are prohibited from exceeding the following smoke opacity levels:

70 percent for model year engines 1973 and older;
55 percent for model year engines 1974 to 1990; and
40 percent for model year engines 1991 and newer.

View and Download the Following Relevant Regulations and Statutes:

Transportation Article Sections 23-401 to 23-404