Missouri OS/OD Overview
Permit Required
Yes – all oversize or overweight loads require a permit from the Missouri Department of Transportation (MoDOT).
Legal Limits (Without Permit)
- Width: 8'6"
- Height: 13'6"
- Length: 53' trailer; 65' overall (combo)
- Weight: 80,000 lbs GVW
Permitted Load Maximums (Typical Upper Limits)
- Width: Routine permits to 16'; over 16' on a 2-lane undivided highway, or over 18' on a divided highway, brings in the Highway Patrol
- Height: Over 15'6" requires a height detection vehicle ahead of the load; over 17' also requires written utility-company approval to disturb aerial lines
- Length: Routine permits to 150'; over 150' requires a Highway Patrol escort
- Weight: Over 160,000 lbs with axle spacing and bridge analysis
Superloads require review by MoDOT’s Bridge Division and may take longer to approve.
Travel Hours
- Standard: Sunrise to sunset once width exceeds 12'6"
- Sunday: No travel, statewide — not just for the wide ones
- Holidays: No travel on New Year's Day, Memorial Day, July 4, Labor Day, Thanksgiving or Christmas. The “from noon the day before” cutoff that appears further down this page is older compiled text; 7 CSR 10-25 gives me the six days and nothing about the preceding afternoon. It is the stricter reading, so plan to it, but confirm it on the permit rather than treating it as the rule.
- Night travel: Rarely allowed; must be specifically authorized on the permit
Escort Requirements (7 CSR 10-25)
| Dimension | Escort Requirement |
|---|---|
| Width over 12'6" — two-lane road | 1 civilian escort, in front |
| Width over 12'6" — divided highway | 1 civilian escort, at the rear |
| Width over 14' — all road types | 2 civilian escorts, front and rear |
| Width over 16' on 2-lane undivided, or over 18' on divided | Missouri State Highway Patrol escort |
| Height over 15'6" | Height detection vehicle — Missouri's own term for the pole car. It must precede the load and hold continuous two-way communication with the power unit |
| Height over 17' | Missouri State Highway Patrol escort, plus written utility-company approval before aerial lines are disturbed |
| Length over 110', combination unit — all highways except divided | 1 civilian escort, at the rear |
| Length over 125', combination unit — all highways, divided included | 1 civilian escort, at the rear |
| Length over 150' | Missouri State Highway Patrol escort |
Every trigger above is exclusive. The rule says “exceeding,” so a load measuring exactly 12'6" wide needs no escort and one measuring exactly 15'6" high needs no height detection vehicle. A lot of sites publish Missouri's first width trigger as “over 12 feet” — the rule reads “exceeding twelve feet, six inches (12'6").” Source: 7 CSR 10-25.030(8)(G).
Additional Notes
- “Oversize Load” signs, red/orange flags, and amber beacon lights are required
- Bridge restrictions, detours, and height clearances must be checked on permit route
- Permits issued via MoDOT’s MODOT Carrier Express System
Detailed Information
PERMITS: Permits valid for seven days. Must have permit prior to entering the state.
OPERATING TIME: Sunrise to sunset once the load is wider than 12'6". There is no Sunday travel anywhere in the state — the version that circulates, and that this page used to carry, has Saturday and Sunday both open except for loads over 14 feet wide, and it is wrong about Sunday. Travel times are more limited in metropolitan and tourist areas (see Restricted Travel section below). One older line on this page reads that overweight-only loads up to 112,000 pounds gross at legal size may travel 24 hours except in metro and tourist areas. I cannot square a 24-hour allowance with the Sunday prohibition in 7 CSR 10-25, and I have not confirmed the exception with MoDOT, so treat Sunday as closed until they tell you otherwise.
RESTRICTED TRAVEL: No travel on New Year's Day, Memorial Day, July 4, Labor Day, Thanksgiving or Christmas, and none from noon the day before those holidays or holiday weekends. No Sunday travel at all. 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 are not allowed on routes in Lake of the Ozarks and Branson (within 10 miles of Branson), with the exception of route 65 in Branson area. Tourist season means June 1 through Labor Day at Lake of the Ozarks and through October 31st in 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.
LEGAL DIMENSIONS: Width: 8'6" on Interstate and designated highways; 8' on other roads. Height: 14' on designated highways, 13'6" on other roads. Over height loads must be on 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 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: Width: 16' Height: 16' (15'7" maximum on some routes) Length: 150' Weight: 5 axles – 104,000 6 axles – 120,000 7 axles (1-3-3) – 130,000 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.
ESCORTS: Width: over 12'6" – 1 escort, in front on a two-lane road and at the rear on a divided highway; over 14' – 2 escorts, front and rear, on all road types; over 16' on a 2-lane undivided highway or over 18' on a divided highway – Missouri State Highway Patrol escort. Length: a combination unit over 110' – 1 rear escort on all highways except divided highways; over 125' – 1 rear escort on all highways, divided included; over 150' – Missouri State Highway Patrol escort. Height: over 15'6" – a height detection vehicle, which is Missouri's own name for the pole car. It has to precede the load, carry a vertical clearance detection device, and hold direct, continuous, uninterrupted two-way communication with the power unit; it satisfies a front escort requirement except where more than one front escort is prescribed. Over 17' high adds a Highway Patrol escort and written approval from the utility company before aerial lines are disturbed. All of these triggers are exclusive — the rule says “exceeding,” so a load sitting exactly on the number is under it. Cites: 7 CSR 10-25.030(8)(G), 7 CSR 10-25 (9)(G)3, (15)(C). The older numbers that still circulate on escort sites — 1 escort over 12'4", and a rear escort starting at 90' of length — are not what the Missouri rule says.
MISCELLANEOUS: If 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 front and rear of the load vehicle when width exceeds 10'6", and on the rear of the load when overall length exceeds 90'. Flags are required at the extreme ends or projections of all overwidth and overlength loads.
