Filtering and splitting are not the same maneuver
Lane filtering is moving between lanes past traffic that has stopped. Lane splitting is riding between lanes of traffic that is still moving. In ordinary conversation the two words get used interchangeably; in a statute they do not, and the distinction decides whether what you just did was legal.
Colorado’s Department of Transportation puts the line in one sentence: “Lane filtering allows motorcyclists to safely navigate through stopped traffic. Lane splitting, which remains illegal, involves riding between lanes of moving vehicles.” That is the shape of every American filtering law written so far. Five states have authorized filtering. None of them has authorized splitting, and the one state where splitting happens legally — California — got there by a different route entirely.
If what you want is the position in your own state rather than the mechanics, the state-by-state map is in the national lane splitting picture. This page is about what filtering actually is and the exact numbers each state attached to it.
The five states where lane filtering is legal
| State | In force since | Traffic must be | Max speed for the motorcycle | Road condition |
|---|---|---|---|---|
| Utah | May 2019 | Stopped | 15 mph | Speed limit 45 mph or less, two or more lanes each way |
| Montana | 2021 | Stopped or under 10 mph | 20 mph | Lanes wide enough to pass safely |
| Arizona | 2022 | Stopped | 15 mph | Speed limit 45 mph or less, two or more lanes each way |
| Colorado | 7 August 2024 | At a complete stop | 15 mph | Pass on the left only; expires September 2027 |
| Minnesota | 1 July 2025 | Stopped, for filtering | 15 mph over the speed of traffic | Two or more lanes in the same direction |
Five laws, five different numbers. That is the part the summaries skip, and it is the part that matters when you cross a state line.
Utah, the first one
Utah legalized filtering in May 2019 and wrote the tightest version of it. All of the following must be true at once: the road’s speed limit is 45 mph or lower, it has two or more lanes in the same direction, the vehicles being overtaken are stopped, the motorcycle is traveling at 15 mph or less, and the movement can be made safely. The state’s own Ride to Live program adds two limits people miss: filtering is not legal on the freeway or on on-ramps, though it is allowed on off-ramps, and riders may not use the shoulder or a bike lane to do it. Once traffic starts moving, the rider must merge back into a lane as soon as possible.
Montana, the outlier
Montana is the only one of the five that does not require traffic to be fully stopped. Montana Code Annotated 61-8-392 defines lane filtering as overtaking a 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 conditions are that the lanes are wide enough to pass safely, that the motorcycle is not operated above 20 miles an hour while overtaking, and that conditions permit continued reasonable and prudent operation.
Montana therefore allows the maneuver against slow-moving traffic, at a higher speed, and without a posted speed-limit ceiling on the road. It is the most permissive filtering law in the country, and it is the one most often misdescribed as matching Utah’s.
Arizona
Arizona Revised Statutes 28-903 allows a two-wheeled motorcycle to overtake between lanes only when the road is divided into at least two adjacent traffic lanes in the same direction, the speed limit does not exceed 45 miles per hour, the motorcycle travels at no more than 15 miles per hour, and the vehicles being passed are stopped. Arizona’s version reads almost word for word like Utah’s. Our full state page is is lane splitting legal in Arizona.
Colorado, and the date on it
Colorado’s Senate Bill 24-079 took effect on 7 August 2024 and is the newest of the five. CDOT lists five conditions: traffic must be at a complete stop; the motorcycle must not exceed 15 mph while passing; it must pass on the left of the vehicle in front; the lane must be wide enough to pass safely; and when the stopped vehicles begin to move, the rider must re-enter the flow of traffic. Passing on the right shoulder is prohibited, as is crossing the centre line into oncoming traffic.
The detail nobody repeats: the law has an expiry date written into it. CDOT states that “this law will automatically expire in September 2027,” pending a state report on its effect. Unless the legislature acts, Colorado’s filtering law ends on its own. The full page is is lane splitting legal in Colorado.
Minnesota, the broadest
Minnesota’s law took effect on 1 July 2025 and is the only one that addresses both maneuvers. For filtering, where two or more lanes run in the same direction and traffic is not moving, a motorcycle may move through it at no more than 15 mph over the speed of the traffic in the relevant lanes. Minnesota also permits a limited form of splitting: passing in the same lane and direction at no more than 25 mph and no more than 15 mph over the speed of surrounding traffic. The statute additionally places a duty on other drivers not to intentionally impede a motorcyclist who is filtering lawfully.
California does something else entirely
California is on every list of “states where lane splitting is legal”, and the reason is a piece of legislation that does not say what people think it says. Vehicle Code section 21658.1 defines lane splitting — and that is all it does. The section contains no prohibition, no express authorization and not a single speed figure. Splitting is lawful in California because nothing forbids it, not because a statute permits it under conditions.
One line of that definition does bite: it applies to a motorcycle with “two wheels contacting the ground”. A trike or a sidecar outfit is outside the definition, which means the rider of one has no defined maneuver to point to. The detail is in is lane splitting legal in California.
What “stopped” means, and where riders get caught
Four of the five filtering statutes hang on the word stopped, and it is doing real work. Traffic crawling forward at walking pace is not stopped in Utah, Arizona or Colorado. The moment the queue starts to roll, the permission ends and the rider is required to be back in a lane — Colorado and Utah both say so explicitly.
The second trap is the speed of the motorcycle rather than the traffic. Fifteen miles per hour is slower than most riders think when they are moving past a stationary queue. It is roughly a fast jog. A rider who filters at 25 mph past stopped cars in Colorado has broken the condition even though everything else about the maneuver was lawful.
The third is geography. Utah excludes freeways and on-ramps. Colorado excludes the right shoulder and the oncoming lane. Arizona and Utah both require a posted limit of 45 mph or lower, which rules out most of the roads where a rider would want to filter in the first place.
Everywhere else, it is illegal
In the remaining 44 states and the District of Columbia, filtering between lanes is not authorized. In most of them the prohibition is explicit: the state’s motorcycle lane statute bans operating between lanes of traffic or between adjacent rows of vehicles, and contains no exception of the kind Utah, Montana, Arizona, Colorado and Minnesota added to theirs.
Two states worth checking because riders assume otherwise: Washington and New Jersey both prohibit it, and neither statute carries a filtering carve-out. We cover both on is lane splitting legal in Washington and is lane splitting legal in New Jersey.
The rules that change at a state border are mostly these two: the lane rules and the helmet rule. The second is mapped in helmet laws by state. And if you are riding on a permit rather than a full endorsement, note that permit conditions often bar this kind of maneuver regardless of the state’s filtering law — see the restrictions on a learner permit.
Frequently asked questions
What is lane filtering?
Lane filtering is riding a motorcycle between lanes to pass vehicles that have stopped, typically at a traffic signal or in a queue. It differs from lane splitting, which is passing between lanes of traffic that is still moving. Five states have made filtering legal under set conditions; splitting remains illegal in every state that has legislated on it.
Which states allow lane filtering?
Utah since May 2019, Montana since 2021, Arizona since 2022, Colorado since 7 August 2024 and Minnesota since 1 July 2025. Each sets different conditions, and Colorado’s law is written to expire in September 2027 unless the legislature extends it.
What is the difference between lane filtering and lane splitting?
Filtering is done past stopped traffic; splitting is done past moving traffic. Colorado’s transport department puts it directly: filtering lets riders move through stopped traffic, while splitting, which remains illegal, means riding between lanes of moving vehicles.
How fast can you filter?
It depends on the state. Utah, Arizona and Colorado cap the motorcycle at 15 mph. Montana allows up to 20 mph. Minnesota frames it as no more than 15 mph above the speed of surrounding traffic. Exceeding the cap removes the protection even if every other condition is met.
Is lane filtering legal on the freeway?
Not in the states that have addressed it. Utah excludes freeways and on-ramps, though it permits filtering on off-ramps. Utah and Arizona both restrict the maneuver to roads with a speed limit of 45 mph or lower, which excludes freeway travel in practice.
Why is lane splitting legal in California but not filtering?
California never passed a statute authorising either. Vehicle Code section 21658.1 defines lane splitting without prohibiting or expressly permitting it and without setting any speed figure. Splitting is lawful there because nothing forbids it, which is a different legal position from the conditional permissions written in Utah, Montana, Arizona, Colorado and Minnesota.