Idling Laws: Do They Apply To Semi Trucks?

Idling laws vary across the United States, with no federal regulations limiting truck idling. However, more than half of the states and many cities and counties have enacted idling laws. These laws are aimed at reducing air pollutants and fuel consumption, and apply to all semi-trucks, though some states provide exemptions for certain types of equipment. For example, Wyoming prohibits idling outside business or residential areas, while Delaware, Washington DC, and New Jersey allow idling for 3 minutes with exceptions for cold weather. Texas does not have a state law, but individual counties and cities have their own regulations, with a 5-minute idling allowance and exemptions.

Idling laws by state

Idling laws vary from state to state in the US, and they can be tricky to remember, especially in states with larger, more regulated cities. While there are no federal limits on idling time, emissions laws have been enacted by a growing number of states and municipalities. As of 2024, 31 states and the District of Columbia regulate how much time trucks can spend idling, although some of these laws are limited to specific counties or municipalities.

• Arizona: Commercial passenger transportation or school purposes can idle up to 30 minutes in any 60-minute period. If temperatures are above 75°F, passenger buses can idle up to 60 minutes in any 90-minute period.
• Colorado: If the temperature is less than 10°F, a driver may idle for 20 minutes in any 60-minute period when they need to warm or cool their sleeper berth during rest or sleep periods.
• Connecticut: A driver may idle if the temperature is less than 20°F.
• Delaware: A driver may idle if the temperature is between -10°F and 32°F for no longer than 15 consecutive minutes.
• Georgia: In Macon, drivers may idle for a maximum of 25 minutes if the temperature is less than 32°F.
• Illinois: In certain cities and counties, drivers may idle for 30 minutes in any 60-minute period while waiting to load or unload freight. There is no time limit if the temperature is below 32°F or above 80°F.
• Maine: Drivers may idle for air conditioning or heating during rest or sleep periods. If the ambient temperature is 32°F or below, a motor vehicle can idle for up to 10 minutes beyond the limit to operate heating equipment.
• Michigan: In Detroit, a diesel-fueled truck can remain motionless for more than two hours if the ambient temperature is continuously below 25°F.
• Minnesota: If the outside temperature is between 32°F and -10°F, idling to operate heaters is allowed for up to 15 minutes. If the temperature is below -10°F, there is no time restriction on idling to use heating equipment.
• New Hampshire: Drivers may idle five consecutive minutes longer if the temperature is above 32°F, 15 minutes longer if between -10°F and 32°F, and there are no restrictions if the temperature is below -10°F.
• New Jersey: Drivers can idle for 15 minutes in a 60-minute period if the temperature is less than 25°F.
• New York: Extended idling is allowed if drivers are parked for more than two hours and the temperature is less than 25°F.
• Ohio: In Cincinnati, drivers may idle for 10 minutes in any 60-minute period if the temperature is below 32°F or above 85°F.
• Oregon: Commercial vehicles with a gross vehicle weight rating of more than 26,000 lbs can idle for air conditioning or heating during rest or sleep periods if the outside temperature is less than 50°F or greater than 75°F.
• South Carolina: Drivers may idle if the temperature is less than 40°F or greater than 80°F.
• West Virginia: Drivers may idle if the temperature is below 40°F or above 75°F.
• Wisconsin: In Madison, drivers may idle if the temperature is below 40°F or above 80°F.
• Wyoming: Idling is not allowed outside business or residential areas, but there are no restrictions on open stretches of road.

It is important to note that these laws are subject to change, and there may be additional city or county-specific regulations within each state.

No federal idling laws

There are no federal laws limiting idling time for semi-trucks. However, this does not mean that truckers are free to idle indefinitely. While there is no federal regulation, more than half of US states and many cities and counties have implemented their own idling laws and ordinances. This means that truckers need to be aware of the specific laws in each state and local jurisdiction they travel through.

The absence of federal idling laws does not mean that there are no federal initiatives to address the issue of idling emissions. In 2018, the Trump administration announced the CLEANER TRUCKS INITIATIVE (CTI) to reduce nitrogen oxide (NOx) emissions from semi-trucks and engines. While the CTI will impose new emissions standards, it is expected to ease other regulations, such as changing annual testing requirements and allowing alternative technologies for compliance.

The Environmental Protection Agency (EPA) has also played a role in addressing idling emissions. In 2016, the EPA set new emissions standards specifically targeting pollution caused by idling trucks. However, the EPA has not promulgated any regulations regarding vehicle idling and instead sees its role as facilitating the creation of more consistent idling laws across the country. The EPA's SmartWay transport program has also developed and encouraged the use of various technologies and strategies to reduce long-duration idling.

The lack of federal idling laws means that truckers must navigate a patchwork of state and local regulations. These laws can vary significantly, but they all share the common goal of minimising unnecessary diesel engine emissions, especially in populated areas. The most common idling limits range from 3 to 15 minutes, with many states and local jurisdictions providing exemptions for factors such as traffic congestion, outside temperature, and emergencies.

Idling laws and temperature

Idling laws are in place to limit emissions, particularly in residential areas and near schools. While there are no federal laws limiting idling time, many states and municipalities have enacted their own laws. These laws vary greatly across the United States, with some states imposing a complete ban on idling outside of business or residential areas, and others allowing idling for a certain number of minutes.

Temperature plays a significant role in idling laws. In many states, exceptions are made to idling restrictions when temperatures are extremely high or low. For example, in Delaware, drivers are allowed to idle for up to 15 consecutive minutes if the temperature is between -10 and 32 degrees Fahrenheit. In New Jersey, drivers are allowed to idle for 15 minutes in a 60-minute period if the temperature is less than 25 degrees Fahrenheit. In South Carolina, drivers are exempt from idling restrictions if the temperature is less than 40 degrees or greater than 80 degrees Fahrenheit.

Some states have more complex, tiered systems that allow longer idling times at colder temperatures. For example, in New Hampshire, drivers may idle for five consecutive minutes longer if the temperature is above 32 degrees, 15 consecutive minutes longer if the temperature is between -10 and 32 degrees, and if the temperature is below -10, there are no idling restrictions.

In extremely cold states such as Minnesota, idling restrictions are lifted entirely when temperatures reach a certain low. In Minnesota, if the outside temperature is below -10 degrees Fahrenheit, there is no time restriction on idling to use heating equipment.

In addition to state laws, some cities and counties have their own idling restrictions and exceptions based on temperature. For example, in the city of Macon, Georgia, drivers may idle for a maximum of 25 minutes if the temperature is less than 32 degrees Fahrenheit. In Detroit, Michigan, a diesel-fueled truck may remain motionless for a period exceeding two hours if the ambient temperature is continuously below 25 degrees Fahrenheit.

Idling laws and fines

Idling laws vary across the United States, and it can be challenging to keep track of them, especially in states with larger, more regulated cities. These laws are in place to reduce emissions from large engines and to protect the health and safety of communities, particularly children, and the environment.

State Laws

No Idling

Wyoming: No idling outside business or residential areas.

3 Minutes Allowed

• Delaware: No idling for more than 3 minutes.
• District of Columbia (Washington, D.C.): No idling for more than 5 minutes, with an exception for operating a heater in freezing temperatures.
• Hawaii: No idling for more than 3 minutes.
• Virginia: No idling for more than 3 minutes.

5 Minutes Allowed

• California: No idling for more than 5 minutes, with specific regulations about where, when, and how to avoid polluting the air.
• Maine: No idling for more than 5 minutes, with exceptions for weather and loading/unloading.
• Maryland: No idling for more than 5 minutes.
• Massachusetts: No idling for more than 5 minutes.
• New Hampshire: No idling for more than 5 minutes, with weather-dependent time limits.
• New York: No idling for more than 5 minutes.
• Oregon: No idling for more than 5 minutes.
• Pennsylvania: No idling for more than 5 minutes, following Californian laws as the standard.
• Rhode Island: No idling for more than 5 minutes.
• Texas: No idling for more than 5 minutes, with exemptions for certain cities and months.
• Utah: No idling for more than 5 minutes.
• Vermont: No idling for more than 5 minutes.

10 Minutes Allowed

• Illinois: No idling for more than 10 minutes, or 30 minutes if weighing, loading, or unloading.
• South Carolina: No idling for more than 10 minutes, with exemptions for sleeping and temperature.

15 Minutes Allowed

• Nevada: No idling for more than 15 minutes.
• West Virginia: No idling for more than 15 minutes, following Californian emissions law.

City/County Laws

• Arizona: Commercial passenger transportation or school purposes can idle up to 30 minutes in any 60-minute period.
• Colorado: If the temperature is less than 10 degrees, idling is allowed for 20 minutes in any 60-minute period for warming or cooling a sleeper berth.
• Connecticut: Idling is allowed if the temperature is less than 20 degrees.
• Delaware: Idling is allowed for up to 15 minutes if the temperature is between -10 and 32 degrees Fahrenheit, and there is no time limit if the temperature is below -10 degrees.
• Georgia: In Macon, idling is allowed for up to 25 minutes if the temperature is less than 32 degrees.
• Illinois: In Aux Sable, Goose Lake, and Oswego, and several counties, idling is allowed for 30 minutes in any 60-minute period while waiting to load or unload freight. There is no time limit if the temperature is less than 32 degrees or greater than 80 degrees.
• Maine: Idling is allowed for air conditioning or heating during rest or sleep periods, with an additional 10 minutes allowed if the temperature is 32 degrees or below. There is no time limit if the temperature is below 0 degrees.
• Michigan: In Detroit, a diesel-fueled truck may idle if the ambient temperature is continuously below 25 degrees.
• Minnesota: If the temperature is between 32 and -10 degrees, idling is allowed for up to 15 minutes to operate heaters. There is no time limit if the temperature is below -10 degrees.
• New Hampshire: Drivers may idle for 5 minutes longer if the temperature is above 32 degrees, 15 minutes longer if the temperature is between -10 and 32 degrees, and there is no time limit if the temperature is below -10 degrees.
• New Jersey: Idling is allowed for 15 minutes in a 60-minute period if the temperature is less than 25 degrees.
• New York: Extended idling is allowed if drivers are parked for more than 2 hours and the temperature is less than 25 degrees.
• Ohio: In Cincinnati, idling is allowed for 10 minutes in any 60-minute period if the temperature is below 32 or above 85 degrees.
• Oregon: In commercial vehicles with a gross vehicle weight rating of more than 26,000 lbs, idling is allowed for air conditioning or heating during rest or sleep periods if the temperature is less than 50 or greater than 75 degrees.
• South Carolina: Idling is allowed if the temperature is less than 40 or greater than 80 degrees.
• West Virginia: Idling is allowed if the temperature is below 40 or above 75 degrees.
• Wisconsin: In Madison, idling is allowed if the temperature is below 40 or above 80 degrees.

Fines and Penalties

While the fines for violating truck idling laws vary depending on the state and the severity of the violation, they can range from a few hundred to several thousand dollars per incident. For example, in Texas, the idling time allowed is five minutes (with exemptions), and fines vary across jurisdictions.

To avoid fines and penalties, truck drivers and companies should adopt practices to minimize idling, such as using auxiliary power units (APUs) or battery-powered HVAC systems, and stay informed about the laws and regulations in the states where they operate.

Idling laws and exemptions

While there are no federal regulations limiting truck idling, more than half of US states and many cities and counties have enacted idling laws. These laws apply to trucks operating within their jurisdictions, including out-of-area vehicles in transit. The purpose of these laws is to reduce air pollutants, such as nitrogen oxide (NOx), and cut fuel consumption.

State and Local Laws

State and local idling laws vary significantly, but they all aim to minimize unnecessary diesel engine emissions, especially in populated areas. The most common idling limits range from 3 to 15 minutes. Most states and local laws have exemptions from idling standards, which vary widely. These often include fixed exemptions, such as truck size (less than 8,000 lbs. GVWR), or variable conditions, such as traffic congestion, outside temperature, emergencies, and driver sleeping or resting.

• Wyoming – Idling an unattended vehicle outside a business or residential area is illegal. This does not apply to open stretches of road.
• Delaware – Idling of a vehicle over 8,500 pounds gross vehicle weight for more than three minutes is prohibited, with some exceptions.
• Washington DC – Motor vehicles powered by gasoline or diesel are limited to three minutes of idling while parked, stopped, or standing. An exception is made for operating a heater when it's freezing outside, extending the time to five minutes.
• New Jersey – The state has a three-minute idling rule with exceptions for sub-freezing temperatures and sleeping berths.
• Arizona – Commercial passenger transportation or school purposes can idle up to 30 minutes in any 60-minute period. If temperatures are above 75 degrees, passenger buses can idle up to 60 minutes in any 90-minute period.
• Colorado – A driver may idle for up to 20 minutes in any 60-minute period if the temperature is less than 10 degrees and they need to warm or cool their sleeper during rest or sleep periods at designated locations.
• Illinois – In certain cities and counties, drivers may idle for 30 minutes in any 60-minute period while waiting to load or unload freight. There is no time limit if the temperature is less than 32 degrees or greater than 80 degrees.

Federal Initiatives

While there are no federal limits on idling time, the federal government has introduced initiatives to reduce emissions from semi-trucks. In 2018, the CLEANER TRUCKS INITIATIVE (CTI) was announced to decrease NOx emissions from on-highway semi-trucks and engines. Additionally, the Environmental Protection Agency (EPA) has set emissions standards for diesel-fueled auxiliary power units (APUs) used during rest periods.

Frequently asked questions