Is Lane Splitting Legal in Montana? (2026 Lane Filtering Law)

Montana allows lane filtering, not lane splitting through moving traffic. Under MCA 61-8-392, the operator of a two-wheeled motorcycle may overtake and pass a vehicle that is stopped or traveling no faster than 10 miles an hour in the same direction and the same lane, at no more than 20 miles an hour, on a road with lanes wide enough to pass safely, and only when conditions permit continued reasonable and prudent operation. Riding between lanes of traffic moving faster than 10 miles an hour falls outside that section, so the single-lane rule in MCA 61-8-328(1) and the passing rules in 61-8-323 and 61-8-324 govern it. A violation of these rules is a misdemeanor with a first-conviction fine of $10 to $100 under MCA 61-8-711. For how other states treat the same maneuvers, see our guide to lane splitting laws by state.

Information last verified on 2026-10-09. This article has not been reviewed by a licensed lawyer.

Jurisdiction scope: This article covers Montana state law in the Montana Code Annotated (MCA) 2025: the lane filtering statute (61-8-392) and its enacting act (Chapter 52, Laws of 2021), the default effective-date rule (1-2-201), the laned-roadway, passing and motorcycle operation rules (61-8-323, 61-8-324, 61-8-328, 61-8-359), the definitions in 61-1-101, the basic speed, reckless driving and careless driving rules (61-8-301, 61-8-302, 61-8-303), the penalty sections (61-8-711, 61-8-715, 61-8-716), the work-zone rule (61-8-314), the meaning of a conviction for driver records (61-5-213) and the point schedule (61-11-203). It does not cover city or county ordinances, local bond amounts, insurance consequences, or the law of other states.

What Montana's lane filtering law says

Montana has a statute that expressly authorizes a motorcycle to pass stopped or slow traffic in the same lane. The full text of MCA 61-8-392 reads:

"(1) An operator of a two-wheeled motorcycle may engage in lane filtering when: (a) the operator of a two-wheeled motorcycle is on a road with lanes wide enough to pass safely; (b) the overtaking motorcycle is not operated at a speed in excess of 20 miles an hour when overtaking the stopped or slow-moving vehicle; and (c) conditions permit continued reasonable and prudent operation of the motorcycle while lane filtering. (2) As used in this section, 'lane filtering' means the act of overtaking and passing another vehicle that is stopped or traveling at a speed not in excess of 10 miles an hour in the same direction of travel and in the same lane."

The three conditions in subsection (1) are joined by "and," so a rider must meet all of them at once. Two speed limits work together. The vehicle being passed must be stopped or moving no faster than 10 miles an hour, and the motorcycle may go no faster than 20 miles an hour while it overtakes.

The permission belongs to "an operator of a two-wheeled motorcycle." Montana's general definition of a motorcycle in MCA 61-1-101 is broader: "a motor vehicle that has a seat or saddle for the use of the operator and that is designated to travel on not more than three wheels in contact with the ground." A three-wheeled motorcycle meets that definition but is not a two-wheeled motorcycle, so 61-8-392 does not reach it.

When the law took effect

The Legislature passed the filtering law as Senate Bill 9 of the 2021 session, printed as Chapter 52, Laws of 2021, "AN ACT PROVIDING FOR MOTORCYCLE LANE FILTERING." The act was approved March 2, 2021, and directs that its first section be codified in Title 61, chapter 8, part 3, the rules of the road. The act sets no effective date of its own, so Montana's default rule in MCA 1-2-201 applies: a statute adopted after January 1, 1981, "takes effect on the first day of October following its passage and approval unless a different time is prescribed in the enacting legislation." That makes the effective date October 1, 2021. The history line of 61-8-392 in MCA 2025 lists only Chapter 52, Laws of 2021, and the act contains no expiration date.

Filtering, splitting, shoulders and riding two abreast

Riding between lanes of moving traffic

Once the traffic being passed is moving faster than 10 miles an hour, the filtering law no longer applies, and the general lane rule takes over. MCA 61-8-328 provides:

"Whenever a roadway has been divided into two or more clearly marked lanes for traffic, the following rules, in addition to all other consistent rules, apply: (1) A vehicle must be operated as nearly as practicable entirely within a single lane and may not be moved from the lane until the operator has first ascertained that the movement can be made with safety;"

The rule applies on any road with two or more clearly marked lanes, not only on multi-lane freeways. Riding along the line between two lanes of moving traffic is not operating "as nearly as practicable entirely within a single lane."

Montana's motorcycle operation statute, MCA 61-8-359, does not carry the model-code sentence many states use to ban riding between lanes outright. It does set a general standard for every ride: under subsection (9), "A person operating a motorcycle or quadricycle shall operate the motorcycle or quadricycle in a reasonable and prudent manner at all times."

Riding on the shoulder and passing on the right

The shoulder answer starts with what Montana calls the roadway. MCA 61-1-101 defines it this way:

"'Roadway' means that portion of a highway improved, designed, or ordinarily used for vehicular travel, exclusive of the berm or shoulder."

A rider on the shoulder is off the roadway. MCA 61-8-324 sets the limits on passing on the right:

"(1) The operator of a vehicle may overtake and pass on the right of another vehicle only under the following conditions: (a) when the vehicle overtaken is making or about to make a left turn; or (b) on a roadway with unobstructed pavement of sufficient width for two or more lanes of vehicles moving lawfully in the direction being traveled by the overtaking vehicle. (2) The operator of a vehicle may overtake and pass another vehicle on the right only under conditions permitting safe movement. The movement may not be made by driving off the pavement or main-traveled portion of the roadway, except that a person operating a bicycle may pass on the shoulder, provided the movement may be done in safety."

The shoulder exception names bicycles and no other vehicle. The filtering law does not mention shoulders at all; it covers passing a vehicle "in the same lane." Marked bicycle lanes are also off limits: under 61-8-328(6), "A motor vehicle may not be driven or parked in a bicycle lane that is signed and delineated as a bicycle lane by official traffic control devices."

Full use of a lane and riding two abreast

Section 61-8-359 protects every vehicle's lane and lets two motorcycles share one:

"(6) No more than two motorcycles may be operated side by side in a single traffic lane. (7) All motor vehicles, including motorcycles and quadricycles, are entitled to the full use of a traffic lane, and a vehicle may not be driven or operated in a manner that deprives any other vehicle of the full use of a traffic lane, except that motorcycles may, with the consent of both drivers, be operated no more than two abreast in a single traffic lane."

Riding two abreast is a separate matter from filtering. It needs the consent of both riders, and it never allows a third motorcycle in the same lane.

What happens if you are caught

The fine for a lane, passing or filtering violation

None of 61-8-323, 61-8-324, 61-8-328, 61-8-359 or 61-8-392 contains a penalty clause of its own, so the chapter's general penalty applies. Under MCA 61-8-711(1), "It is a misdemeanor for a person to violate any of the provisions of this chapter unless the violation is declared to be a felony." Subsection (2) sets the fines for a violation "for which another penalty is not provided":

The statute sets a range, not a fixed amount. Under 61-8-711(5), "the court costs or any part of the court costs may be assessed against the defendant in the discretion of the court."

In a work zone

MCA 61-8-314 reaches every rule in part 3 of chapter 8, which includes the filtering, lane, passing and motorcycle sections. A traffic violation in a work zone is a misdemeanor, and if a highway worker was present in the work zone at the time "and within 1,000 feet of the traffic violation," the fine is "not less than double the penalty provided for the violation in part 7 of this chapter." With no worker present, the ordinary part 7 penalty applies.

Paying the ticket counts as a conviction

For driver-record purposes, MCA 61-5-213 treats as a conviction "a forfeiture of bail or collateral deposited to secure the person's appearance in court that has not been vacated" and "the payment of a fine or court cost, regardless of whether it is suspended or rebated." Forfeiting bond or paying the fine on a lane or passing ticket therefore goes on the record as a conviction.

Points

Montana's conviction point schedule in MCA 61-11-203 does not list lane filtering, lane use or passing by name. Its catch-all, subsection (2)(m), assigns "all other moving violations, 2 points." A lane or passing violation on a highway is a "moving violation" as 61-11-203(1)(d) defines it ("a violation of a traffic regulation of this state ... while operating a motor vehicle ... upon a highway"), so it falls under that catch-all. Reckless driving carries 5 points and speeding 3 points (except as provided in 61-8-725(2)(a)), and when two or more convictions involve a single occurrence, only the points for the conviction carrying the highest points are chargeable (61-11-203(3)). A person who accumulates 30 or more conviction points within a 3-year period is a habitual traffic offender under 61-11-203(1)(b).

Other rules and heavier charges

Reckless and careless driving are separate charges with their own elements; whether a particular ride meets them depends on the facts. A between-lanes stop can also involve the general speed rule:

A rider who filters within the limits of 61-8-392 is doing what the statute allows. A rider who splits lanes in faster traffic faces a single-lane or passing charge under the general rules, and a reckless driving charge only if the riding shows willful or wanton disregard for the safety of persons or property, as 61-8-301(1)(a) requires.

Recent changes and open points

The filtering law has not changed since it was enacted: the MCA 2025 history line of 61-8-392 shows only Chapter 52, Laws of 2021. The passing rule in 61-8-324 was last amended in 2015, the lane rule in 61-8-328 in 2003, the motorcycle operation statute 61-8-359 in 2017, the general penalty section 61-8-711 in 1995, and the reckless driving sections 61-8-301 and 61-8-715 in 2023.

Several 2025 acts touched sections near this topic:

• Chapter 255, Laws of 2025 (House Bill 312), amended 61-8-303 and 61-8-725 to set a 75 mph daytime and 70 mph nighttime limit on national highways expanded to four lanes and to add those highways to the speeding fine schedule. The basic speed rule in 61-8-303(3) reads as quoted above, and the fine amounts in the table are the schedule as amended.
• Chapter 47, Laws of 2025, amended 61-8-303 and the definitions in 61-1-101, and Chapters 395 and 693, Laws of 2025, also amended 61-1-101. The "roadway" and "motorcycle" definitions quoted above are the text as it reads in MCA 2025.

Local courts may use their own bond amounts within the statutory fine ranges, and this page does not list them.

Federal law and lane splitting

We found no federal statute or regulation that addresses lane splitting or filtering; the rules come from state traffic law. The federal motorcyclist safety grant rule, 23 CFR 1300.25, sets criteria for training, motorist-awareness and impaired-riding programs and says nothing about lane use, and NHTSA's motorcycle safety guidance does not mention splitting or filtering. Montana's rule comes from state law.

If a crash happens while filtering or splitting

Whether a rider stayed within the filtering conditions, or rode between lanes outside them, can come up after a collision. How it bears on fault, insurance and an injury claim is covered in our guide to Montana motorcycle accident laws. For the rules that apply to crashes generally, see Montana car accident laws.

Related pages

• Lane splitting laws by state
• Montana motorcycle accident laws
• Montana car accident laws
• Idaho lane splitting laws
• Wyoming lane splitting laws

This article provides general legal information about Montana law, not legal advice. For advice about a specific situation, contact a lawyer licensed in Montana.

Last updated: 2026-10-09.

Frequently Asked Questions

Is lane splitting legal in Montana?

Not through moving traffic. MCA 61-8-392 allows only lane filtering, passing a vehicle that is stopped or moving no faster than 10 miles an hour; riding between lanes of faster traffic falls under the single-lane rule in MCA 61-8-328(1).

Is lane filtering legal in Montana?

Yes, for two-wheeled motorcycles. Under MCA 61-8-392, a rider may pass a vehicle that is stopped or traveling 10 miles an hour or less in the same direction and lane, on a road with lanes wide enough to pass safely, at no more than 20 miles an hour, when conditions permit continued reasonable and prudent operation.

How fast can you lane filter in Montana?

No faster than 20 miles an hour while overtaking (MCA 61-8-392(1)(b)), and only past vehicles that are stopped or traveling no faster than 10 miles an hour (61-8-392(2)).

When did lane filtering become legal in Montana?

October 1, 2021. Senate Bill 9 (Chapter 52, Laws of 2021) was approved March 2, 2021, and set no effective date, so Montana's default rule in MCA 1-2-201 made it effective on the first day of October following passage.

Can motorcycles ride on the shoulder in Montana?

Not to pass traffic. MCA 61-8-324(2) bars passing on the right by driving off the pavement or main-traveled portion of the roadway, and its shoulder exception applies only to bicycles; the filtering law in 61-8-392 does not mention shoulders.

Can a three-wheeled motorcycle lane filter in Montana?

No. MCA 61-8-392 applies only to the operator of a two-wheeled motorcycle, even though Montana's general definition of a motorcycle in 61-1-101 includes vehicles on up to three wheels.

What is the fine for illegal lane splitting in Montana?

Under MCA 61-8-711, a violation is a misdemeanor with a fine of $10 to $100 for a first conviction, $25 to $200 for a second within one year, and $50 to $500 for a third or later within one year, plus court costs at the court's discretion. The fine is at least doubled in a work zone with a highway worker present within 1,000 feet (61-8-314).

Can two motorcycles ride side by side in one lane in Montana?

Yes, with the consent of both drivers, and never more than two. MCA 61-8-359(6) and (7) allow no more than two motorcycles abreast in a single traffic lane.