Buckle Up: New Montana Driving Law To Make Major Changes

A summary of the key information is provided at the bottom of the article.

BUTTE, MT - Driving through Montana’s roundabouts may never be the same again.

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A new law—passed unanimously by the state House—will give towing vehicles the legal right to veer outside their lane when maneuvering through traffic circles, forcing other drivers to yield.

And yes, this is as big of a deal as it sounds.

Let’s break down what this means, why it’s happening, and how this may change your daily drive.

Towing Vehicles Now Take the Wheel—Literally

If you’re hauling livestock, a camper, or anything else that doesn’t exactly corner like it’s on rails, you’re in luck.

SB 433 legally allows towing vehicles to deviate from their lane while entering or exiting a roundabout. And if you're just driving your SUV or sedan? You’ll need to yield because towing vehicles now have the right-of-way.

Sen. Theresa Manzella, R-Hamilton, brought the bill forward after hearing complaints from her constituents in the Bitterroot Valley, especially near the Highway 93 roundabout at Bell Crossing.

From horse owners to commercial haulers, the message was clear: towing through a roundabout is like threading a needle with a bulldozer.

Double-Lane Roundabouts: A New Set of Rules

The bill doesn’t stop at simple single-lane roundabouts. It also applies to multi-lane roundabouts, which are becoming more common on four-lane highways.

Towing vehicles will now be allowed to legally cross from one lane into another when navigating these circles, giving them more flexibility—and less risk of clipping curbs, berms, or other cars.

This change acknowledges the very real physics of towing: trailers don’t follow perfectly behind.

They crowd the inside of turns, and without room to maneuver, things can go south quickly.

The Montana Department of Transportation (MDOT) is backing the bill, too.

MDOT maintains a full database of roundabouts across the state and agrees this change improves safety without compromising the overall goal of roundabouts—reducing severe crashes like T-bone collisions.

Is It a Done Deal? Almost.

With full bipartisan support in both chambers and MDOT backing, SB 433 is almost guaranteed to become law.

It now heads to Governor Greg Gianforte’s desk for final approval. And given the bill’s unanimous House vote, a veto seems highly unlikely.

Once signed, Montana drivers will need to brush up on their roundabout etiquette, because hauling vehicles will legally be taking the wide turns they've (allegedly) always needed.

Conclusion

In Montana, where road-tripping with a trailer is more a way of life than a luxury, this law makes sense. It adds nuance, safety, and realism to an intersection style that has long been a point of confusion for drivers across the U.S.

So next time you’re approaching a roundabout, take a look in your mirrors. If there’s a trailer behind you, don’t just yield out of courtesy—you’ll have to.

Because in Montana, the roads just got a little more interesting.

Summary:

Montana's House has unanimously passed Senate Bill 433, a new law that changes how drivers approach roundabouts—specifically giving the right-of-way to vehicles towing trailers.

Backed by both lawmakers and the Montana Department of Transportation, the bill allows towing vehicles to legally deviate from their lane while navigating single and double-lane roundabouts, citing safety concerns and real-world challenges faced by haulers.

The legislation, introduced by Sen. Theresa Manzella, stems from complaints about tight turns and trailer instability, especially near Victor on Highway 93. With only the governor’s signature left, the law is poised to take effect soon.