The smoking vehicle program is intended to lower the number of vehicles with visible tailpipe emissions that drive on the streets of Denver. This can include emissions from the engines of cars, motorcycles, trucks, or buses. The smoking vehicle ordinance maintains and improves the air quality in the City and County of Denver. Because of a growing number of vehicles, the Denver metro area could face an increasing incidence of poor air quality in coming years. The combination of all vehicles giving off unnecessary contaminants contributes significantly to smog problems in the region.

For example, a vehicle with a poorly running engine frequently burns fuel incompletely, which results in an excess emission of smoke. This smoke can contain pollutants such as unburned hydrocarbons, small particles, or carbon monoxide. An individual car or truck that is out of compliance with emissions standards can add up to 13 tons of carbon monoxide into the air per year. The pollution can be damaging to everyone's health, but is especially dangerous for those with heart, lung, or other existing health problems. The smoking vehicle ordinance exists to improve the health and well-being of the citizens of Denver and the environment by helping to keep the air free of pollution.

SMOKING VEHICLE FAQ's

1) Q: How do I know if my vehicle violates the ordinance?

A: For gasoline engines:

If the exhaust from your tailpipe is visible, then it is in violation of the smoking vehicle ordinance. For instance, if you have black, blue, or gray-white smoke coming from the tailpipe of your car, it is in violation of the law.

However, low temperatures can cause a billowy, white smoke to come from your tailpipe. This is normal for all engines and is not considered in violation of the ordinance.

A: For diesel engines:

Because diesel fuel burns differently from gasoline, diesel engines are permitted to have some visible smoke, even when they are running properly. Diesel engines are allowed to have visible smoke if it is at less than 20% opacity.

Opacity is a measure of the ability to "see through" smoke. The emissions from the tailpipe of your vehicle are at 0% opacity when there is no visible smoke; if there is thick smoke that you cannot see through, the emissions are at 100% opacity.

2) Q: Are smoking vehicles really any worse than other vehicles?

A: EPA estimates 20% of the vehicles driven produce half the pollution! In fact, a badly smoking vehicle can emit 2600 pounds of carbon monoxide per year while newer vehicles emit less than 150 pounds per year.

3) Q: How do I report a smoking vehicle?

A: Anyone who sees a vehicle smoke for over ten seconds in the City and County of Denver can call in the license plate, make and model, date and time, and location to 720-865-5452. For smoking vehicle complaints outside of Denver, please call 303-692-3211.

Throughout the 1980's, stricter federal emission guidelines for vehicles led to several technological advancements in engine design including catalytic converters, fuel injection, and oxygen sensors. Although, these advances significantly contributed to the reducing the days Denver exceeded the federal standards--by 1990 only three exceedences were reported--Denver was still classified as non-attainment for carbon monoxide by the EPA.

The non-attainment status provided the impetus to pass additional legislation during the 1990's to further reduce mobile source pollution. The idling vehicle ordinance was passed in 1990 prohibiting vehicles within the city limits to idle more than 10 minutes in any one-hour period of time.