Permits valid for seven days. Must have a permit prior to entering the state.
Missouri permitting system: https://mcs.modot.mo.gov/mce/login.htm
Contact phone number: 1-866-831-6277
One-half hour before sunrise to one-half hour after sunset, including Saturday and Sunday, except that loads over 14 feet wide will not be allowed weekend travel. Travel times are more limited in metropolitan and tourist areas (see Restricted Travel section below). Overweight only up to 112,000 pounds gross with legal-size may travel 24 hours except for metro and tourist areas.
No travel on major holidays, and from noon the day before these holidays or holiday weekends. No travel weekdays from 6:30 a.m. to 9:00 a.m. and 3:30 p.m. – 6:30 p.m., in St. Louis city and county (except for route 370), St. Charles County on I-70, Route 94 and route 40/61 and, and Jefferson County on I-55 and on routes 21, 30, 141 and 61/67. No travel from 7:00 a.m. to 9:00 a.m. and 4:00 p.m. – 6:00 p.m. in the Kansas City area on routes 150, 291, I-470, 291, 152 west to I-435 and inside the area bounded these routes, and inside the city limits of Springfield except on I-44 and Route 65. These metro area curfews do not apply to loads that are overweight only. No permit movement is allowed on Mississippi River bridges in St. Louis on I-70, I-55, I-64, and on route 60/62 to Cairo, IL. During the tourist season, Saturday and Sunday travel is not allowed on routes in Lake of the Ozarks and Branson (within 10 miles of Branson), with the exception of route 65 in the Branson area. Tourist season means June 1 through Labor Day at Lake of the Ozarks and through October 31st in the Branson area. These curfews are listed in more detail in part 9 of the MO Permit Regulations Booklet, which is available to drivers and should be carried if you do O/D loads in Missouri.
Width: 8'6" on Interstate, designated highways; 8' on other roads
Height: 14' on designated highways, 13'6" on other roads. Overheight loads must be on the drop-deck trailer to be permitted.
Length: 53' semi-trailer and load (including rear overhang) on Interstate and designated highways; 60' when more than 10 air miles from the designated system.
Weight: 80,000 Gross Single – 20,000 (22,000 on secondary) Tandem – 34,000 (36,000 on secondary) Tridem – 34,000 (8' of spacing), 42,500 (9' of spacings)
Note: Missouri will not give a permit for legal gross weight, but overweight on an axle group.
ROUTINE PERMIT LIMITS:
Height: 16' (15'7" maximum on some routes)
Weight: 5 axles – 104,000 6 axles – 120,000 7 axles (1-3-3) – 132,000 Single – 20,000 Tandem – 46,000 (40,000 on a 10' spread) Tridem – 60,000 Quad – 72,000
Note: A 1-2-2-1 (tandem drive tractor, tandem trailer, and booster) combination is not permittable in Missouri. You must have a Tridem drive tractor to use a tandem trailer and a booster. Loads exceeding these dimensions or gross weight over 160,000 pounds are considered as Super Loads.
Width: Over 12'4" – 1 escort (2 escorts off the designated highway system); over 14' – 1 escort on Interstate and divided highways, 2 escorts required on 2-lane and undivided highways
Length: Over 90' – 1 escort on all highways except divided highways
Height: Over 15'6" on 2-lane & undivided, and over 16' divided highways – route survey and 1 escort. A utility bucket truck may be required to lift wires.
If the trailer is stretched, Missouri wants to know how much used and unused space is in well, and on front and rear decks.
SIGNS, FLAGS & LIGHTS:
"Oversize Load" signs are required on the front and rear of the load vehicle when the width exceeds 10'6", and on the rear of the load when the overall length exceeds 90'. Flags are required at the extreme ends or projections of all over width and overlength loads.