Vehicle Emissions Fact Sheet ( PDF )
Free to download, print & distribute.

Over a period of years we have tried to tell state and federal officials that the mandates embodied in the Clean Air Act of 1990 were based on incorrect assumptions, faulty science and hidden or self-serving agendas. One of the more counterproductive elements of this law is the wholesale expansion of universal automobile inspection programs.

Mandating emissions inspections of the entire vehicle fleet benefit the manufacturers of testing equipment, contractors that conduct the tests, the automotive repair industry and the bureaucracy that evolves to regulate the inspection and certification process. Mandated emissions inspection systems are very expensive, complicated, intrusive, inconvenient and value the citizens’ time at zero. The ultimate insult is that mandated universal emissions inspection systems do not significantly improve air quality.

The most onerous of the inspection technologies, known as “IM 240” can indeed measure emissions down to the most minute levels. The issue at hand is do we need to employ this kind of technology to clean the air? Should we spend billions of dollars creating a testing infrastructure that, if deployed as proposed by EPA, will do little more than punish motorists?

There is an alternative that will cost far less and improve air quality far more. Its an alternative that targets the more serious polluters, with an emphasis on repairing defective vehicles rather than punishing errant motorists.

The logical solution is to identify the defective vehicles before they are brought into the inspection/repair system. The inspection /repair system should be used to confirm the existence of a defect, diagnose the cause and specify the needed repair.

Vehicles with moderate to serious emissions problems can be identified through the use of roadside remote sensing equipment. Traffic is not interrupted. Motorists with vehicles in good repair are not marched through inspections stations, at great expense and irritation. And, inspection and diagnostic professionals can concentrate on defective cars, not the crowds of angry drivers that wait in line, most of whom have “clean” cars.

Here’s how it can work.


Mobile teams working varied shifts and locations would operate remote sensing devices that measure the emissions of passing vehicles and photograph the license plates of vehicles with high emissions. (This technology already exists)


Licence plate numbers would be used to identify the owners of the defective vehicles. Letters would be sent to the vehicle owners describing the general program, providing a list of certified inspection/diagnostic centers and setting a liberal time frame during which the inspection should take place. Compliance with the inspection/diagnosis requirement would be enforced through equipment violation penalties and the withholding of vehicle registration. (The registration would be “flagged” at the time the letter was sent.) The emphasis of the letter would be on fixing the problem, not threatening the recipient.


The inspection/diagnostic facilities could be state-operated or state-certified private businesses. The state would set standards for personnel and equipment requirements and operational procedures.

The vehicle owner would not be charged for the inspection/diagnosis service. If the vehicle passes the inspection the inspection/diagnostic center will notify the state to lift the flag on the registration. If a vehicle has an emissions defect the cause will be identified and repairs will be specified. The owner will be given a reasonable time frame in which to have the specified repairs made. (Waivers and limits are options.)


The vehicle owner would have the option of having the vehicle repaired at a state certified emissions repair facility, a non-certified repair facility or to do the repairs him/herself. To fulfill the regulatory requirements and to lift the registration restraint, only those repairs specified by the state certified or operated inspection/diagnostic center would need completion. Even if the repairs failed to correct the emissions problem the vehicle owner would be given a one year waiver excusing he or she from further “forced” repairs. If, after a year, the vehicle was again identified as a high emitter it would be processed through the system.

Following repair at a state certified repair facility the state would be notified to lift the registration restriction on the repaired vehicle. Vehicles repaired by their owners or non-certified repair facilities would have to be taken to state certified inspection/diagnostic centers or state certified emissions repair facilities to have the repairs inspected and the registration restriction lifted. Note that the purpose is not to retest the vehicle but to insure that the specified repairs have been made. (a retest could be requested by the vehicle owner if he or she felt that repairs, other than those specified, corrected the emissions problem.)


The state would be responsible for funding the remote sensing program, establishing and enforcing certification standards for inspection/diagnostic centers and repair facilities and enforcing compliance with the inspection/ diagnostic requirements. Another important role for the state is the monitoring of state certified repair facilities to insure that proper repairs were being executed and that consumers were not being persuaded to make unnecessary repairs or purchases.

All contacts with the vehicle registration agency would be made by the inspection/diagnostic center or state certified repair facility. The vehicle registration agency would have to develop procedures for notifying vehicle owners, flagging registrations of vehicles identified for inspection and removing the flag when notified of properly completed repairs. Registration records would also be required to note date of last inspection to prevent the owner from being continually re-run through the system because his or her vehicle is identified as a high emitter, even after repairs have been completed or a waiver is granted. (Courtesy notices could be sent, suggesting the vehicle should be inspected and repaired.)


To avoid a punitive connotation the inspection/diagnostic function should be funded by a tax applied to all vehicles, e.g. fuel tax, registration fee or a related broad-based tax, given that everyone benefits from clean air. The certification of repair facilities and the monitoring of these facilities could be at least partially funded by fees levied on the certified shops.


  • The goal is clean air, not punishing motorists.
  • The highest priority targets of the remote sensing program will be vehicles with very high emissions.
  • The onus is on the state or state contractor to properly inspect the vehicle and diagnose the emission problem, on the first visit to the inspection and diagnostic facility.
  • The state, not the vehicle owner, is responsible for all paperwork.
  • State certification of emission repair facilities will denote a high level of competence, capability and integrity.


The relatively small capital investment for remote sensing equipment is in itself a major improvement over stationary inspection facilities. Because a remote sensing based program will only identify the vehicles most likely in need of repair there will be far fewer vehicles moving through the inspection (and diagnostic) centers, meaning fewer such centers will have to be built and operated, publicly or privately.

Most vehicles that are properly maintained will never be forced into a mandatory inspection system. The vehicles most likely to be identified as high emitters will also be vehicles that are driven a great deal within the non-attainment zone. The likelihood of not identifying high emitters that are seldom driven does exist. However, these vehicles are not responsible for a large share of the overall emissions burden.

A remote sensing based program can be phased in slowly, allowing adjustments and modifications to accommodate unexpected obstacles or challenges. Remote sensing activity can be adjusted to accommodate the capacity of the inspection and diagnostic centers. Such a system can also be adjusted to identify the worst emitters first and then identify less severe emitters as inspection and diagnostic capacity is freed up.

(It should be noted that the physical and professional infrastructure needed for an effective emissions inspection, diagnostic and repair system does not exist. A program that will allow gradual development and systematic expansion will save billions of dollars and avoid significant political backlash.)

The remote sensing and inspection/diagnostic functions can be carried out by public agencies or private contractors. Repair services would remain within the private sector.

Because this system would operate continually, vehicles suffering an emissions failure would be more likely to be identified soon thereafter, rather than a year or two later when they would otherwise report for a mandated inspection. A sophisticated diagnostic center staffed with professionals whose area of expertise is emissions systems has a high probability of identifying the cause of failures. The fact that they do not carry out repairs removes any incentive to recommend unneeded repairs.

There will be no “ping-pong” effect associated with this program. The vehicle owner will be given specific repair requirements. When those repairs are certified as being completed the vehicle owner’s obligation is completed.

Because real emissions and real air quality will be measured, versus computer simulation, there will be a continuous record of vehicle emissions and regional air quality. This will provide information on the programs effectiveness as well as help document the true impact of vehicle emissions on overall air quality. Lastly, when the need for emissions inspections is made obsolete by new technology, this program can be very easily dismantled.

NMA Position on Vehicle Emissions

The NMA supports emissions reduction programs that are cost effective and that do not place onerous, time consuming and expensive burdens on vehicle owners.

Join The NMA

NMA Vehicle Emissions Fact Sheet

Download, Print & Distribute (PDF)