“Bicycles Ride Single File” signs: law or suggestion?

From The Cyclist Lawyer

We got a great question in our inbox from a Boulder-area cyclist:

“Hi Megan, I appreciated your recent blog post on riding two-abreast in Colorado. It solidified my understanding of how this state law applies to cyclists in practice.”

This week I had an encounter on Four Mile Canyon Dr west of Boulder with an extremely aggressive driver. He was enraged that our group did not single up quickly enough (or more accurately, that we were riding two abreast at all). While out of his vehicle threatening to assault us, he claimed that the presence of yellow “Bicycles Single File in Four Mile Canyon” signs required us to ride single file at all times. My understanding is that these yellow signs are advisory in nature, much like the yellow reduced speed limit signs that precede a corner. They do not trump posted speed limits or state law. Is this an accurate assessment? Or, do these signs overrule the state law on two abreast cycling that you discuss in your blog post?

These signs are common in other Boulder County canyons, so it’s a question that is widely applicable to local cyclists. The residents of Four Mile Canyon Dr. however seem to be particularly hostile towards cyclists with regard to two-abreast riding.”

The short answer is: those signs are not laws, they are suggestions.

I also consulted one of our best contacts in Boulder County law enforcement and he concurred: “The signs came about after a working group comprised of county transportation, fire, law, mountain area citizens, cyclists, etcetera, met to address issues. I was part of the group that met soon after the 2013 floods. You may remember Four Mile, Lefthand, Jamestown and St. Vrain canyon roads were severely damaged. Most have been repaired as of this year.

Even after the rebuilding there are many sections of our canyons that are narrow and, while legal to ride two abreast, it’s hazardous for the cyclists on the blind curves. These signs were installed to encourage safe cycling.

I don’t see any mention that she reported the incident but if she didn’t I would encourage her to do so in the future.” (Sidenote: Remember, cyclists, you can call *277 to report menacing drivers to the CSP aggressive driver hotline, or you can call the local authorities to report this kind of conduct!).

In short: those signs are placed in areas where it is really best and safest to ride single file – the signs were placed with intention and not randomly. While they are not law, they are suggestive of best practices given the curves, road conditions and so on.

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  1. Dennis Olsen

    I’ve run into an old idiot on 4 Mile Canyon that was yelling at me to get off the road. I’d strongly encourage you to call the police on that douchebag.

  2. Josh Abram

    Ya know, it doesn’t really matter if its optional or required, its the safest way for cyclists to ride on 4 mile. Hands down. Get off your high bike and ride safely FIRST, then worry about socializing with your riding mates. Sheesh! This is a no brainer. I’m in my mid 50s and have been riding since I was a teen. Ride single file, doofus! And stop complaining. I’d be pissed if was that motorist too. You do nothing as ambassadors for the sport by insisting the road is yours to ride any way you wish. Really stupid and frustrating. Get a clue.

    • Sorry, but...

      Josh, sorry but you’re wrong. Riding two abreast is actually safer for cyclists AND it makes it easier for cars to pass safely, because no matter how many people are riding together, a group that’s two abreast takes up half as much linear space on the road as a group that’s single file.

      If you think you can pass safer because a group of cyclists is half as wide by riding single file, you’re passing too closely anyway.

      • Canyon resident

        Title 42 section 6. It is the law for cyclists on roadways to ride single abreast.

  3. Mike Parrish

    Was it a guy in a older white Jeep? My friends and I had a run in with him last summer. If so he lives in Wallstreet in the paved section. Then there is the gentleman that lives on Gold Run at the first 90 degree corner in Sunset. He yells at cyclists all the time.

    • Mike Parrish

      I made a mistake. Salina, not Sunset. I always get the two mixed up. Even after riding up that way for 20+ years…. Do’h.

  4. Anonymous

    “The signs came about after a working group comprised of county transportation, fire, law, mountain area citizens, cyclists, etcetera, met to address issues.”…’Nuff said.

    Many miles of Boulder County roads are not suitable for two-abreast, and it would cost the county a lot of money to place a sign in every single place that single-file riding is suggested. Signs were limited, and placed at the bottom to alert riders this is the case for the entire stretch of road.

    Reasons NOT to ride two (or more) abreast in 4mile, Sunshine, Lefthand, etc:
    –It’s dangerous.
    –The closer you are to the center line, the more danger you are in.
    –Visibility is poor.
    –The more lane you take up, the more lane the overtaking driver has to take up. This puts at risk the oncoming traffic including both cars and other cyclists.
    –You do not live there. It is primarily a residential road, not a theme park.
    –If you do live there, you know that it is dangerous and you already ride single-file.
    –If you are involved in an accident, it puts a strain on local resources including fire/rescue and possible road closures.

    • Sorry, but...

      You are as mistaken as Josh.

      The closer to the edge, the more danger you are in.
      The closer you are to the edge, the more likely a driver will try to pass you without crossing the center line. When a vehicle passes without crossing the center line, the more likely it is there is not enough room to pass safely.
      Drivers should, by law, wait until it is safe to pass and if there is oncoming traffic in the opposite lane, it is not safe to pass.
      If visibility is poor, it is because you are driving too fast. Slow down. Driving too fast causes accidents and puts a strain on local resources.

      We’re all human beings, whether in a car or on a bike. Getting to your destination a few seconds sooner is not worth the risk of killing someone. Try driving a little more relaxed and a little more considerate of your fellow man. You’d be surprised what it’ll do for your mental well being. You’ll be a lot less stressed.

      • Canyon resident

        When someone comes around a corner and the bikers are in the lane or double abreast it is harder to react quickly if they need to avoid rear ending you, and the driver does not even have to be speeding for this to be a problem.

        You should respect the cars on the road and they should respect you, so don’t ride double abreast or in the middle of the road just to prove a point.

  5. Canyon resident

    For everyone using this article and the comment section as an argument for riding double abreast… please stop.

    When you are in the middle of the road or double abreast, it is not safe in the twisting canyons. Cars should wait behind you and pass you safely… but make it easier on them and they can make it easier on you.

    It’s not a battle. It’s letting everyone get home alive.


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