Maximum width on interstates, highways, roads. Commercial or private.

What is the maximum width on highways, roads and interstates?

What is the maximum width allowed on Interstates and highways (all reasonable access roads or what is referred to as the “National Network” or “NN”)? The maximum width allowed on Interstates and highways in North America is (unless otherwise posted by sign):

Standard:
8 feet and 6 inches or 102.36 inches.

Metric:
2.6 meters or 260 centimeters.

Exceptions:
Within the state of Hawaii commercial motor vehicles are permitted the following maximum width on all highways (unless otherwise posted by sign):

Standard:
9 feet or 108 inches.

Metric:
2.74 meters or 274 centimeters.

Notes: These rules are for personal, commercial motor vehicles including semi tractors, trailers and buses. Mirrors and other items such as “mirrors” or “certain safety devices” (such as flags, etc.) are not included and may protrude out within a reasonable distance further. It should also be noted that there are county roads that do not support the maximum widths governed by federal guidelines. These roads usually have signs posted that display the maximum legal width permitted with out obtaining a special travel permit. You should always inquire about the maximum widths permitted by the governing body of the particular road prior to travelling on it in order to prevent a fine or worse. In some situations depending on the width of the vehicle or shipment size a route survey will be required prior to being granted permission to travel.

Maximum width allowed.

Maximum width laws are created to protect motorists and public assets. Know the maximums.

The importance of setting maximum widths for vehicles.

Safety of motorists and public property are the main reasons regulations were set for vehicle width maximums. A standard was required based on the dimensions of the existing roads that would protect any/all persons operating a motor vehicle on highways, roads and interstates. It should also be noted public property is placed at risk for damage as well. Should a motorists accidentally hit one of the many existing obstructions such as guard rails, signs, traffic signal poles, etc. liability while ultimately is the motorists, if it is not reported the state is required to repair damages which then is passed on to the taxpayers in both the USA and Canada. So maximum widths were created to protect both human lives but public property as well.

Maximum width allowed

Maximum vehicle width permitted on highways. Image credit FHWA.

Noteworthy information:

“Federal width limits do not apply to special mobile equipment, which consists of self-propelled vehicles not designed or used primarily for the transportation of persons or property and only incidentally moved over the highways. Special mobile equipment includes the following, when moving under their own power: military or farm equipment; instruments of husbandry; road construction or maintenance machinery; and emergency apparatus, including police and fire emergency equipment. Federal rules do not require States to issue overwidth permits before allowing operation of special mobile equipment. However, if States wish to allow other vehicles more than 102 inches wide (i.e. non-special mobile equipment) to operate on the NN, then States must issue special overwidth permits.” Reference credit: FHWA website.

History:

“The Federal Government first enacted size regulations for CMVs with the passage of the Federal-Aid Highway Act of 1956. This Act provided a maximum vehicle width of 96 inches (2.44 meters) on the Interstate highway system. Subsequently, the Federal-Aid Highway Act of 1976 increased the allowable width for buses to 102 inches (2.6 meters). The Surface Transportation Assistance Act (STAA) of 1982 extended the same width requirement of 102 inches to commercial trucks. At the same time, the STAA expanded the highway network on which the Federal width provision applied from the Interstate to the National Network (NN) of highways.” Reference credit: FHWA website.

 

Related links:

See regulations for maximum load limitations.
Learn what a route survey is.
Maximum length allowed on roads, highways and interstates.
Maximum legal load sizes.
Multi state and regional permits.

 

 

Maryland State Shipping Regulations

Maryland state shipping regulations, limitations, rules and laws for the trucking of oversize and heavy haul loads over the roads and highways in the state of Maryland.

 If you would like to share your knowledge with others please do so at the bottom of this page.

 

Maryland oversize regulations.

Legal Loads.

Length: 65’ (48’ trailers) (53’ allowed on Interstate only with 41’ kingpin).
Overhang: 3’ front and 6’ rear maximum.
Weight: GVW 80,000
Tandem: 34,000
Width: 8’ on non designated highways – 8’6” on designated highways.
Height: 13’ 6”

Routine trucking permits.

Length: 120’
Weight: Less than 110,000 lbs
Width: 16’
Height: 14’ 6” – high pole required!

When you are required to have pilot cars.

Length: Over 120’
Weight: Over 110,000 lbs.
Width: Over 13’ requires 1 pilot car in front. Over 14’ requires 1 pilot car in front and 1 pilot car in rear.
Height: Over 16’.

Travel times and restrictions.

Times that you are not allowed to travel within the state or Maryland with oversize or heavy haul loads:

Daylight hours are defined as one half hour after sunrise and one half hours before sunset. You may not travel on Sunday. Saturday travel is permitted in till noon. Maryland state DOT has different curfews that have to be followed in areas with high traffic densities. Typically these hours are from 9 AM in till 3:30 PM. No travel is usually allow between these hours. The state of Maryland has many toll bridges and tunnels that may charge additional fees. You should contact the Maryland Transportation Authority (US-50:410–537–6601, I95: 410–537–1150, FC Key Bridge: 410–537–7600). Traveling on any of these toll roads bridges or tunnels. Always be sure to check your physical permit for curfew times. Especially if you are in excess of 45 gross tons 100 feet in length or over 12 feet wide. If you are over 14 feet by you will not be permitted to travel between the hours of 9 AM and 3:30 PM on any highway. Travel is not permitted on any of the following holidays: New Year’s Day, Good Friday, Memorial Day, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. The Maryland state DOT permit office for oversize and heavy haul loads is closed on the above-mentioned holidays as well as Martin Luther King Day, Columbus Day, election day and is also close on the day after Thanksgiving but travel is not restricted on these days.

Maryland DOT contact information.

Information and links for oversize and heavy haul shippers:

Maryland State Highway Administration
Office of Traffic Safety, Oversize and heavy haul division
Hauling Permits Unit
7491 Connelley Dr.
Hanover, MD  21076

E-mail: mdmotorcarrier@sha.state.md.us
Phone:  800-846-6435 or 800-543-4564
Fax: 410-787-2863 or toll free fax: 800-945-3416

Hours: are Monday thru Friday 7:30 am to 4:30 pm (closed noon to 1 o’clock).
NOTE: Single trip permits are valid for 5 days and costs $30 – you can view their fees. Also Maryland has a designated area for pilot cars which you can view here.

 

The information contained in these pages is research information primarily for use by oversize and overweight trucking company drivers, dispatchers and pilot car companies. While every effort is put into maintaining the accuracy of this information you must absolutely verify this information with the Maryland State DOT Permits office before commencing movement.

 

 

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