Missouri Truck Lane Restrictions

Which lanes a truck can use in Missouri

Missouri keeps heavy trucks out of the far-left lane, but only in the big metros. If your truck is registered over 48,000 pounds, you can't run the left lane on any interstate, freeway, or expressway inside an urbanized area with three or more lanes each way (RSMo 304.015). That covers St. Louis and Kansas City. On rural three-lane stretches the ban doesn't apply. The only legal reasons to be over there are a lane-control sign directing you or a right side closed for construction.

Roads, exceptions, and signs

• Where it applies: Urbanized areas only. That means the St. Louis and Kansas City metros on roads like I-70, I-64, I-44, and I-270. The stretch must carry three or more lanes each way. Rural multi-lane sections are not covered.
• Statutory. The ban applies inside urbanized areas whether or not a sign is posted, though some metro segments also carry lane-use signs.
• General rule: Slower traffic keeps right; you drive in the right-hand lane unless passing or turning left (RSMo 304.015). Applies to every vehicle.
• Trigger is registered gross weight over 48,000 lbs, not the actual load. "Urbanized area" is a densely populated region, so the ban is a metro rule, not a statewide one.

What a lane violation costs

The base offense is a Class C misdemeanor, not a simple ticket. That is up to 15 days and a fine up to $750 (RSMo 304.015(9)). It rises to a Class B misdemeanor if it creates an immediate crash risk, and a Class A misdemeanor if a crash results.

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