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Heavy Duty Diesel Vehicle Inspection/Maintenance Program

Heavy duty diesel vehicles (HDDVs) play a major role in commercial transportation and operate across NYS, but diesel exhaust has the potential to cause serious health problems (leaves DEC website). In an effort to reduce potentially harmful diesel exhaust emissions, DEC has developed a program to inspect HDDVs and ensure their emission control systems are being properly maintained. DEC has two emission inspection programs for HDDVs:

  1. An annual emission inspection program for HDDVs registered in the New York City Metropolitan Area (New York City, Long Island, Westchester and Rockland Counties).
  2. A roadside emission inspection program for HDDVs operating on New York State roadways.

HDDVs are diesel engine powered vehicles with a Gross Vehicle Weight Rating (GVWR) exceeding 8,500 pounds. Some vehicles in this weight class are exempt, such as authorized emergency vehicles. Both the annual and the roadside emission inspections are conducted by a certified inspector. The emission inspections can include a visual inspection to verify that the vehicle's emissions control equipment is functioning, a check for tampering and an opacity (smoke) test using an approved opacity meter.

DEC maintains a list of approved opacity meters (smokemeters).

Annual HDDV Inspections

The annual emissions inspection is performed at the time of the vehicle's annual NYS Department of Motor Vehicles (NYSDMV) safety inspection. This inspection applies only to HDDVs registered in the New York City Metropolitan Area and must be performed by a certified inspector. A vehicle safety inspection station that performs emissions inspections of HDDVs is authorized by the NYSDMV as an Official Diesel Emissions Inspection Station (ODEIS).

HDDV Roadside Inspections and Standards

Roadside emissions inspections are performed at various times on New York State roadways by NYS certified staff. DEC staff who are certified emission inspectors have the authority to emissions test (smoke test) HDDVs. A HDDV can be roadside inspected regardless of the vehicle's registration location.

Smoke tests measure the opacity of exhaust smoke from the vehicle. Opacity is a measure of the amount of light that cannot pass through a substance, such as the amount of light obstructed as it passes through the exhaust. It is expressed as a percentage. These tests are conducted using an opacity meter, which samples the exhaust smoke at frequent intervals and calculates the smoke coming from the tailpipe. The exhaust smoke will be tested with an Opacity Meter using a Snap Acceleration Test.

  • The wheels will be chocked
  • Transmission in neutral
  • Brakes disengaged to activate all emission control equipment
  • The sensor will be inserted to the end of the exhaust stack
  • The accelerator is rapidly depressed and held for a few seconds, then released. This is repeated a minimum of five times.
  • The meter will average three consistent results and create a print out for your records.

The smoke opacity standards are shown below:

Standards of Emission Failure
Engine Model Year Opacity
1991 or Newer greater than 40%
1974-1990 greater than 55%
1973 or Older greater than 70%

To help the inspection go quicker, make sure the following information is readily available:

  • Make and year of vehicle
  • Mileage
  • Engine manufacturer
  • Horsepower

Improving Smoke Opacity

It is important to maintain and repair a vehicle to ensure it passes the emissions test. Common causes of excessive smoke include:

  • Clogged or worn fuel filters
  • Restricted air filters
  • Contaminated fuel
  • The oil level is overfilled
  • Defective turbochargers
  • Defective or inoperable emissions control devices

Smoke opacity can be improved in several ways:

  • Adjusting emissions control equipment
  • Replacing air filter elements
  • Tuning up your engine
  • Adjusting engine timing
  • Ensuring correct operation of the cooling system
  • Repairing the restricted exhaust system

Penalties for Failing Inspections

No vehicle will be put out of service for failing a roadside opacity test. However, it will result in a fine. Failure of the roadside or annual emissions inspection can result in a penalty of $700 for the first violation and $1,300for the second and each subsequent violation. These penalties can be reduced if the violation is corrected within 30 days.

A retest, which may be done to seek a penalty reduction, must be conducted by an ODEIS. The roadside and/or annual inspection penalties do not apply to school buses or municipally owned HDDVs for a first violation, provided the vehicle is repaired and the violation corrected within 30 days of the cited violation.

Heavy Duty Inspection/Maintenance Program DEC Approved Smokemeters

The approved list of smokemeters will be amended to comply with the implementation of NYVIP 3. This current list of smokemeters will not be compatible with the upcoming NYVIP 3 system.​

Robert H. Wager Co., Inc
570 Montroyal Rd.
Rural Hall, NC 27045
Phone: (336) 969-6909
Approved smokemeter: Wager 7500*

Red Mountain Engineering
17767 Mitchell N.
Irvine, CA 92614
Phone: (949) 595-4475
Approved smokemeter: Smoke Check 1667*

Previously-Approved Smokemeters

The smokemeters listed below are no longer approved for new smokemeter purchases, but are considered valid under the heavy duty inspection/maintenance program if properly maintained and calibrated.

Cal Test Instruments, Inc.
126 Marine Ave.
Wilmington, CA 90744
Phone: (310) 835-6909
Approved smokemeter: CalTest 1000-WIN-TR*

Robert Bosch Corporation
2800 South 25th Ave.
Broadview, IL 60153
Phone: (855) 426-7247
Approved smokemeter: Bosch RTT 100*

Environmental Systems Products, Inc. (ESP)
11 Kripes Rd.
East Granby, CT. 06026
Phone: (860) 392-2162; (800) 695-4377
Approved smokemeter: ESP Diesel-sense 1667*

SPX Corporation
8001 Angling Rd.
Portage, MI 49024
Phone: (800) 233-7055
Approved smokemeter: SPX Dieseltune DX-240*

ProTech USA
No longer in business
Approved smokemeter: Protech OPAX 2000-II*

*Note: The above smokemeters must come equipped with functioning engine oil temperature and engine RPM sensors

(updated March 26, 2020)