Truck Speed Limit Regulations by State

In the United States, there are different speed limit regulations for cars and trucks per each state or jurisdiction — which usually means that the truck speed limit is lower than that of passenger vehicles (depending on various conditions).

These specific speed limits are usually only applicable to large commercial motor vehicles (CMVs) such as trailers, buses, and heavy trucks, and depend on whether it is in urban or densely populated areas, as well as whether it is day or night driving.

Highway speed limits can range from 35 mph (56 km/h) in urban areas to 85 mph (137 km/h) in rural areas. Typically posted in increments of five miles per hour (mph), truck speed limits are set by either the state or the local counties, municipalities or other local statutes. Many jurisdictions have speed limits that are lower for trucks (not light trucks or large passenger vehicles referred to as trucks). 

Be sure to check all posted speed limits and drive according to the conditions of the road. The information listed below is only general information and is only meant to be used as a reference. It should not be considered the legal authority. 

Traditionally, states are responsible for setting speed limits. However, in the mid-1970s Congress withheld funds from states that had speed limits that were higher than 55 mph by passing the National Maximum Speed Law. It was done for a couple of reasons:

• As a response to the 1973 oil crisis, to reduce gasoline consumption. It was done since cars were thought to run more efficiently and use less gas at a speed of 55 mph (this effect on fuel efficiency has been heavily debated.)
• Thought to increase safety. But the impact on safety is unclear as studies and opinions of safety advocates are mixed when it comes to speed limits for trucks.

At the time, motorists widely disregarded the law, and in 1987 the requirements were changed for rural interstates and then completely repealed by 1995. Speed limit choices were again up to the states and today, 41 states have some portions of the roadway system that have speed limits of 70mph or higher.

In rare instances, such as for West Virginia, speed limits are not set by law, but by the Commissioner of the Division of Highways. In Rhode Island, speed limits not set by law, but by state traffic commission. For more information on individual state speed limits or transportation laws, contact the State Highway Safety Offices in each state.

_{*Guam does not have any Interstates. The maximum truck speed limit is 35 in rural areas, 15 in residential areas, 15 or 25 in school zones.}

_{**Based on an engineering and traffic investigation, Pennsylvania truck speed limit is 70 on specific segments.}

_{***Table data was compiled from the Insurance Institute for Highway Safety (IIHS).}