Truck Speed Limit Regulations by State
Why do state laws vary?
In the United States, each state or jurisdiction sets its own speed limit regulations for cars and trucks. While each is different, truck speed limits are often lower than that of passenger vehicles.
These specific speed limits are usually only applicable to large commercial motor vehicles (CMVs) such as trailers, buses, and heavy trucks. They can vary depending on whether the area is rural or densely populated, as well as whether it's day or night driving.
Truck Speed Limit Laws: The Complete List
Highway speed limits can range from 50 mph (80 km/h) in urban areas to 80 mph (128 km/h) in rural areas. Typically posted in increments of 5 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.
|State||Rural Interstates||Urban Interstates||Other Limited Access Roads|
|Montana||70||65||70 Day / 65 Night|
|New Hampshire||65 or 70||65||55|
|Oregon||55 or 65||55||65|
Why Do State Laws Vary?
Traditionally, states are responsible for setting speed limits. However, in the mid-1970s Congress withheld funds from states that had speed limits higher than 55 mph by passing the National Maximum Speed Law. It was done for a couple of reasons:
- Fuel economy: As a response to the 1973 oil crisis, it was considered a gas saver because 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.
- Safety increase: The effect 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. In 1987, the requirements were changed for rural interstates and then completely repealed by 1995.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 in 2019, 41 states have some portions of the roadway system with speed limits of 70 mph 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 are not set by law, but by the state traffic commission. The State Highway Safety Offices in each state can supply up-to-date information on individual state speed limits and transportation laws.
*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.
***Table data was compiled from the Insurance Institute for Highway Safety (IIHS).