Lane Filtering Is Now Legal in Colorado: What Denver Riders Need to Know for 2026
For years the answer to "can I move up between the cars in Colorado" was a flat no. That changed. In 2024 Colorado passed SB 24-079 and became one of the few states to legalize lane filtering, and going into 2026 it is one of the more important rules a Denver rider needs to understand. The line between what is now legal and what is still illegal is narrow, and crossing it does more than earn a ticket. It can hand an insurer the argument that wrecks your injury claim.
Filtering Versus Splitting: The Distinction That Matters
These two words get used interchangeably in the parking lot, but the law treats them as opposites, and the difference is entirely about whether the traffic around you is moving. Lane filtering is now legal: under SB 24-079 you may move past stopped vehicles at 15 miles per hour or less, generally passing on the left of stopped traffic, on a road wide enough to do it safely. The key word is stopped. Traffic is at a standstill, and you are easing forward through it slowly. Lane splitting is still illegal: splitting means riding the line between lanes of traffic that is moving, often at speed, and Colorado did not legalize that. If the cars around you are rolling, filtering rules do not apply and you are back to illegal territory. Get that distinction wrong and you are not filtering within the law, you are splitting, and everything that follows a crash changes.
What SB 24-079 Actually Allows
The law sets specific conditions, and all of them have to be true at once. This is not a green light to weave through traffic whenever it suits you.
- ✓ The vehicles you pass must be stopped. Not slowing, not crawling. Stopped. The moment traffic starts moving, the filtering allowance ends.
- ✓ Your speed must be 15 miles per hour or less. This is a slow, controlled pass, not an acceleration lane. Above 15 and you are outside the law.
- ✓ The road has to be wide enough. You need lanes of travel in the same direction with room to pass safely, typically on the left of the stopped traffic. A narrow two-lane does not qualify.
- ✓ It must be safe to do so. The law builds in a judgment call. If conditions do not allow a safe pass, the allowance does not cover you.
Why Doing It Wrong Hands the Insurer a Weapon
This is where the law matters far beyond a traffic ticket, and it comes down to how Colorado assigns blame. Colorado follows modified comparative negligence with a 50 percent bar. If you are found 50 percent or more at fault for a crash, you recover nothing. If you are less than that, your recovery is reduced by your share of the blame. Now picture a crash while you are moving between cars. If you were splitting through moving traffic, or filtering above 15, or filtering where the road did not allow it, the other driver's insurer will argue you were doing something illegal at the moment of impact. That argument is aimed straight at pushing your share of fault up. Every percentage point they pin on you shrinks your recovery, and if they can get you to 50 percent, they can try to deny the claim entirely under the bar. Filtering legally protects your body and your claim. Filtering illegally, or splitting, does the insurer's work for it.
How to Filter Within the Law on I-25 or C-470
Front Range backups are exactly where this comes up. I-25 through Denver, a C-470 or E-470 slowdown, the crawl toward the Eisenhower Tunnel on I-70. Only filter when traffic is fully stopped, and get back into the lane before it starts rolling again. Keep it slow, at or under 15 miles per hour, so you have time to react and you stay inside the rule. Pass on the left where there is room, and do not force a gap that is not really there. Watch for doors, mirrors, and drivers changing lanes without looking, because a stopped car is not a parked car and people move without warning. And if the road is too narrow or the pass does not feel safe, stay put, because the law rewards the safe call and so does your body. Filtering is a tool for getting out of the dangerous spot at the back of a stopped line of traffic, not a shortcut to the front of every jam.
Confirm the Current Rule Before You Rely On It
Colorado's filtering law is relatively new, and rules like this can be amended, extended, or changed as the state studies how they work in practice. What is described here is the framework as of 2026, built on SB 24-079 and its August 2024 effective date. Before you count on any of it in a specific situation, confirm the current status of the law. Riding on last year's rule is its own kind of risk.
Scott O'Sullivan and the Denver motorcycle accident attorneys at Rider Justice represent riders hurt by negligent drivers. If you have questions after a crash, their team is here to help.