Motorcyclists will soon be allowed to ‘filter’ through gridlock traffic. Here’s what Colorado drivers need to know about the new state law

A new law that will take effect next month in Colorado aims to increase safety for motorcyclists by allowing them to “filter” through stopped traffic.

The Colorado State Patrol (CSP) said in a news release this month that both lane filtering and lane splitting are “controversial.” But while lane filtering will become legal on Aug. 7, lane splitting will remain illegal.

“The first thing Coloradans need to understand is that there is a seemingly small but important difference between lane filtering and lane splitting,” CSP Chief Col. Matthew Packard said in a statement. “One will soon be legal, and the other remains prohibited, so let’s all start by getting on the same page.”

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Lane filtering, which is the act of a motorcyclist passing a completely stopped vehicle traveling in the same direction, will become legal next month under Senate Bill 24-0749. Once legal, CSP expects lane filtering to be most common at stop lights or in gridlocked traffic.

But lane filtering is different from lane splitting, which is when a motorcyclist passes between two rows of moving or stopped traffic and typically involves a motorcyclist riding down the painted line dividing the lanes on either side, according to CSP.

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CSP Trooper Gabriel Moltrer said in an email that the new law aims to allow motorcyclists to filter to the front of the line, aiding traffic flow, while also removing motorcycles from the “vulnerable” position where they are sandwiched between two vehicles in stopped traffic.

While motorcyclists make up less than 3% of all vehicles on the road, motorcyclists represent almost 20% of all transportation deaths, according to the Colorado Department of Transportation (CDOT). In 2023, 134 motorcyclists were reportedly killed on Colorado roads.

“Colorado’s new lane filtering law could save motorcyclists from injuries or death,” Moltrer said. “Lane filtering reduces the chance of motorcyclists being rear-ended by a car or truck in high-volume, stop-and-go traffic. Collisions from behind by larger vehicles can cause serious injury or kill motorcycle riders.”

One of the biggest differences between lane filtering and lane splitting comes down to the movement of surrounding vehicles, according to CSP. Under Colorado’s new motorcycle filtering law, there are five rules that motorcyclists must follow to filter.

First, the vehicle a rider wants to pass must be at a complete stop. The lane must also be wide enough to fit the vehicle and motorcycle while passing. The motorcycle must drive 15 mph or slower. The rider must pass safely and be in control of the motorcycle. Finally, the rider must pass on the left and not enter the oncoming traffic lane.

A motorcycle rider is not allowed to overtake or pass on the right shoulder, to the right of a vehicle in the farthest right-hand lane, or in a lane of traffic moving in the opposite direction, according to the CDOT. Once vehicles resume moving, motorcyclists must stop passing.

Moltrer said that with the new law, other motor vehicle drivers who are stopped will have to be wary that there may be motorcycles passing them, and that those motorcycles will have to reintegrate into the traffic queue when it starts moving again.

Drivers who see motorcyclists or any other vehicle that is not abiding by lane filtering laws should call *CSP, or *277, to report it, he said. If there is a passenger in the vehicle, they can attempt to record the situation. When giving information to law enforcement, those reporting the situation should provide as much information as possible, including vehicle type, color, direction of travel, and, if possible, a license plate, he said.

Riders who do not abide by rules related to lane filtering could face a variety of penalties, depending on the situation, Moltrer said. Violators could be cited with changing lanes while unsafe, a traffic infraction with fees starting at $100, or with reckless driving or careless driving, both traffic misdemeanors with fines over $100.

While motorcyclists will soon be allowed to lane filter, he noted that there is no requirement that riders do so. It is up to riders to make safe decisions about when or when not to filter, he added.

“With the ability to filter in Colorado on Aug. 7, riders will also assume the responsibility to do it safely and legally,” he said. “Filtering is not required. It is an option and can only be exercised legally when the rider follows all five of the rules to filter.”