By Megan Hottman
In Colorado, when a driver overtakes a cyclist, the law is crystal clear: you must allow a minimum of three feet between your vehicle and the person on the bike. This isn’t a friendly tip or best practice—it’s legally required under state law.
What the Law Says
Colorado Revised Statute § 42-4-1003 (law in CO since 2009) states: “The driver of a motor vehicle overtaking a bicyclist proceeding in the same direction shall allow the bicyclist at least a three-foot separation between the right side of the driver’s vehicle, including all mirrors or other projections, and the left side of the bicyclist at all times.”
This applies whether the road is narrow or wide, whether there’s a shoulder or not, and regardless of how much traffic there is. The burden is on the driver to wait until it’s safe to pass with at least a 3-foot buffer.
Why 3 Feet?
Three feet isn’t an arbitrary number—it’s the minimum distance needed to provide a safety cushion for someone traveling unprotected and exposed on two wheels. That space helps account for:
- Wind gusts from fast-moving vehicles
- A cyclist swerving to avoid debris, potholes, or animals
- The natural side-to-side movement of a bike, especially on climbs
- The psychological and physical impact of a close pass
Even a mirror clipping a handlebar can send a rider crashing to the ground. And sometimes, the noise and shock of a vehicle passing too closely can cause a cyclist to panic or lose control.
This law exists because too many cyclists have been hit—or killed—by cars passing too closely. Every inch matters. The 3-foot rule sets a non-negotiable buffer to help prevent tragedy.
But What Does 3 Feet Look Like?
Here’s a list of common, easy-to-visualize items that are each about three feet long:
- A standard yardstick
- A baseball bat
- A golf club
- A guitar
- A broom handle
- A shovel
- A folding camp chair
- Three Subway footlong sandwiches
- Starwars Light Saber
- A Hattori Honzo Sword like that used by Beatrix Kiddo in Kill Bill 1&2
If you’re passing close enough that one of these items could touch your car—or worse, a cyclist’s elbow—then you’re too close. If you wouldn’t want someone passing your child or your friend that closely, give every rider that same courtesy.
What Drivers Must Do
- Slow down when approaching a cyclist from behind.
- Wait until it’s safe and clear to pass.
- Cross the double yellow line if needed—Colorado law allows this when safely overtaking a bicyclist so long as it’s clear of oncoming traffic.
- Do not try to squeeze by, especially on narrow or shoulderless roads.
- Give three feet minimum, more if possible.
This is not up for debate or left to interpretation. If there’s not enough room to pass with three feet, you wait behind the cyclist until there IS room to safely pass.
What If You’re in a Hurry?
Ask yourself: is saving five seconds worth endangering someone’s life? A cyclist is a vulnerable road user—someone’s child, spouse, parent, or friend. You may not know them, but they have just as much right to be on the road as you do. Waiting a few seconds to pass safely is a small ask. You’ll still get where you’re going, and they’ll get home in one piece.
If You Drive Around Colorado
If you drive around Colorado, you are likely to see the 3-Feet-to-Pass signs posted along roads and highways, educating motorists about this law. These signs—and the awareness campaign behind them—are thanks to the advocacy work of Bicycle Colorado, which has championed cyclist safety and helped push for clear, statewide signage. “The new signs, which read “State Law: Motorists Must Give Bicycles 3 Ft Clearance,” replace existing “Share the Road” signage and provide clearer direction to motorists of their legal responsibility to safely interact with bicyclists on the road.”
You can learn more about the campaign and see the signs at:
www.bicyclecolorado.org/three-
feet-signage These visual reminders help reinforce what the law requires and keep the message top of mind: three feet is not optional.
Bottom Line
The 3-foot passing law protects real lives—people who ride bikes to work, for fun, for fitness, for the environment. Respecting this law is the bare minimum we owe each other on the road. Driving safely around cyclists is not just courteous—it’s legally required, morally right, and incredibly simple.
So next time you approach a cyclist on the road, take a breath. Ease off the gas. Wait for the clear opportunity. Then pass safely, with three feet of space or more. They’ll thank you—even if silently—and you’ll both continue your day unharmed.