jwalther

Is anyone aware of academic research on cyclist safety when group riding single file v. two abreast? TIA.

johnny99

All I can say is whenever I see two bicycle police on city streets, they are always riding side by side instead of single file

Kontact 

Generally speaking, bicycles are not the subject of much research and even less data gathering. There is no government or academic entity that does the kind of sampling your question requires.

Daniel4

Generally, I would prefer to ride side by side. It makes sense of taking-the-lane.

I'm guessing the single-file law is to appease the motorists because otherwise too many cyclists will end up blocking the motorist who only want squeeze by you regardless of the three-foot rule.

Motorcycles ride scattered in a lane. Why can't bicycles?

mr_bill

My understanding that Toronto removed single file four years ago? (Waterloo more recently.)

Everyone, double, triple check your (national/state/province/county/parish/city/town) laws, bylaws and regulations. In some cases local regulation is pre-empted. In other cases, court decisions have invalidate regulations.

To say this is a muddled mess is an understatement.

-mr. bill

Kontact 

Because we don't ride at traffic speed most of the time.


Roads exist to allow everyone to get where they need to go, not to exercise everyone's "rights" to use the road in some manner that is not about transportation. If the law says no abreast riding, it is so the inevitable passing will happen with minimal impact.

Bicycles have as much right to use the road as cars or motorcycles, but bicycles are not cars or motorcycles and don't get to pretend they are. We have our own set of restrictions AND privileges not afforded to motor vehicles.

mr_bill

Uh, speak for yourself. I ride faster than motor traffic most of the time. (It’s not that I’m fast, it’s that motor traffic is the traffic they are stuck in.)

-mr. bill

Kontact 

I'm going to speak for both of us when I say that we aren't able to keep up with traffic that is 35mph, let alone 45 or 55. I'm sure you can really shame the cars in school zones, though.

ccinnz

Seconded...

Paul Barnard

I am not aware of any academic research. Since the common excuse when there is collision is "I didn't see..." it stands to reason that a larger object will be easier to see. We appear larger to vehicles in front of us and behind us when we are side by side. It has been demonstrated that a group of cyclists is faster to pass when they are side by side as opposed to strung out.

Daniel4

Cyclists don't need to keep up with anybody. But motorists do need to pass properly, which they don't when they think they have room to squeeze out a vulnerable road user regardless of the 3-foot rule. Single-file allows motorists do that. Two abreast don't.

Fjl229

Wow, really?


Speed only comes into play when a slower moving driver isn’t operating in the correct position on the roadway.

Access to the road is first come first served. If someone is already occupying that space you’re obligated to wait until it’s safe to pass. If you’re already there first it’s the duty of others wishing to use that space to do the same.

Nowhere in the traffic code is a person’s trip purpose prioritized or deemed “more important” by whether they’re on the road for transportation of for recreation. Their trip purpose is not your business and you have no place speculating. Bicyclists (not bicycles, it’s the person, not the vehicle. Bicycles don’t have rights!) have the same rights to the road and are required to follow the same rules as other drivers. Bicyclists obeying traffic laws are not “pretending” to be motorized vehicles either. Motor vehicles are objects controlled by other people, or drivers. The rights and duties are extended to the human, not the object they’re driving.

Kontact 

Your suggesting that cyclists should be in the traffic direction and enforcement business by deciding when we feel drivers can pass us or not. That isn't how our road system and laws work.

The road exists for use as transportation - you don't get to play football in the road if you get there first. The purpose of transportation isn't the issue, but riding abreast isn't a necessity for transportation.

Cars are obligated to wait until it is safe to pass. That isn't the same as saying that cyclists have a right to determine when to allow drivers to pass. The road system works on the premise that everyone is making their own good judgments unless there is a signal or police traffic director. Blocking the road by riding abreast is blocking the road and the cyclists usurping the other road users' discretion.


I get the impulse to forcefully block cars from passing when you don't think they should by riding abreast, but that really isn't much different than a car getting next to you and pushing you into the right side of the lane where they think you ought to ride. It is a use of force that no road user has the right to. Drivers are right to be pissed when their ability to make their own judgments about how to drive in the traffic conditions are being interfered with by abreast riders where that is illegal.

CliffordK

I haven't seen the research, but it is an interesting question.

My preference:

Small groups (2 to 4 people), ride to the right on narrow, busy roads. In some cases one can squeeze two wide into a shoulder or bike path if both wish.

On not very busy streets, ride side-by-side until a car approaches, then have the outside rider either drop back or pull forward into single file.

There seem to be anecdotal reports of road rage. And, I think car drivers and cyclists work better together if they all think they are sharing the road and respecting each other's needs. There was a Recent post of "road rage" after a car couldn't get around cyclists quick enough

Once one gets to larger groups (5+ riders?), then:

• Spread out a bit if the situation allows (road ride).
• Form a draft line if one wishes.
• Or, in some cases, especially in urban areas, it may make sense to group up a bit so the group can pass through stop signs and traffic lights as a group.

I've been in urban groups that enveloped cars, and that doesn't work well, unless it is a huge slow moving group (100+).

IronM

too much 'it depends' variability. road width, lane count; shoulder or bike lane present or not; number of riders, rural vs urban. Personally, in my experience: safety in numbers: any size group is often safer (from cars) than solo. I feel safer in urban (slower traffic) than I do suburban. Safest in lightly travel rural roads. Two abreast on quiet roads (talking, rotating, etc) but if it's a busy two-lane, it's time to single-up.

jon c. 

I never decide when drivers can pass. That's up to them based on whether or not the road is clear. If it's safe to pass, they can do so whether there's a single rider at the right or two riders abreast in the lane. On the roads I ride, it's very rare to be in a situation where you could safely pass one rider but not two. But whether or not the driver does pass is always up to them. Similarly, my position on the road is up to me.

CliffordK

Perhaps our riding is different, but most of my riding is on roads where a car can squeeze past me, and pass an oncoming vehicle, and not hit either.

I do get a bit nervous on bridges and pinch points, and will at times stop or slow down to let following cars past before I cross the bridge.

A couple of roads are too narrow to pass a bike + car, and I'm less concerned with riding down the non-existent fog line, but will still pull to the right to let cars past. Mom's road is narrow enough that it might not be safe to force a car fully into the oncoming lane to pass. That is the road where the local fire department dumped their truck in a ditch when passing an oncoming pickup/trailer on the road.

Kontact 

It isn't up to you when riding abreast is illegal. Nor is it up to you to slow traffic by unnecessarily using up lane space where cars could pass you if you simply made room for them to do so. So I don't understand how your post has much to do with the my answer to what was quoted.

dedhed

WI 346.80 - (a) Any person operating a bicycle or electric personal assistive mobility device upon a roadway at less than the normal speed of traffic at the time and place and under the conditions then existing shall ride as close as practicable to the right-hand edge or curb of the unobstructed traveled roadway, including operators who are riding 2 or more abreast where permitted under sub. (3), except:


(3) 
(a) Persons riding bicycles or electric personal assistive mobility devices upon a roadway may ride 2 abreast if such operation does not impede the normal and reasonable movement of traffic. Bicycle or electric personal assistive mobility device operators riding 2 abreast on a 2-lane or more roadway shall ride within a single lane.

CliffordK

The problem with all these laws is that they are written to be unambiguous, but are still up to interpretation.

"As far right as practicable" is a judgement call, as we know shoulders are often strewn with glass, debris, garbage cans, and there is lots of discussion about doors and parked cars.

Likewise "does not impede the normal and reasonable movement of traffic" is also a judgement call, and one could argue that a car would be unable to safely pass single file bikes any easier than side-by-side bikes, and thus side-by-side doesn't impede traffic any more than simply riding on the road.

Kontact 

It's a judgment, as is all operation on a road. But what it doesn't say is that you can do whatever you want in the lane when there is traffic.

B. Carfree

You omitted a key piece of that law. The exceptions very explicitly include: Thus, a rider legally can, and in fact should, ride towards the center of a substandard width lane (generally accepted as any lane in which it would not be safe for a motorist to pass a cyclist while remaining fully within the lane, which itself is generally accepted to be a lane width of fourteen feet). Most other states have similar wording.

On the typical two-lane road, lane widths under fourteen feet are the norm and it is legal and proper for a cyclist to ride away from the right edge on these roads. Once one rider is there, it matters little where the second rider chooses to be unless it's one of those states that prohibits riding two abreast. In fact, it will be easier for a motorist to pass two riders who are side by side than single file simply because they are a shorter object to pass, so it will take less time.

This is lawful use of the road, not "blocking" or any other loaded term.

noimagination

Thank you. People ask this type of question all of the time without thinking about what they're actually asking.

OP: Think about what you're asking of the "study". You want a study comparing the "safety" of riding 2 abreast vs. single file. Ignoring, for the moment, that you have not defined what "safety" means, for the sake of argument I'm going to assume that you mean "bicycle accident rate (hit by car) per mile traveled" (even this is probably not precise enough).

In order to compare the two riding modes, you'd have to have the following data:
Miles traveled by bicycles riding single file.
Miles traveled by bicycles riding 2 abreast.
Accidents between autos and bicycles while bicycles were traveling single file.
Accidents between autos and bicycles while bicycles were traveling 2 abreast.
Then you'd have to control for a variety of additional factors where the likelihood of the accident is not affected by single file vs 2 abreast riding, for example:
- accidents between cyclists and oncoming car
- accidents between cyclists and car entering the roadway
- etc.

The data needed are not collected. I don't think that there is any database listing the number of cycling miles single file, 2 abreast, 3 abreast, etc. So, you'd have to come up with a methodology for estimating the numbers, and you'd have to justify the methodology.

Also, accident reports are not collected this way - there is no database listing car/bike accidents and whether the cyclists were riding single file or 2 abreast (or 3, or 4, or....), nor many other factors that might affect whether or not single file vs 2 abreast might have an effect on the likelihood of the accident. So, the researcher would have to read all auto-bike accident reports individually to determine whether they fit into the data set. Again, it would be difficult, if not impossible, to formulate unambiguous criteria, so the researcher would probably be forced to make judgments that would be open to challenge.

Once all of that was done, they would have to determine if there were a sufficient number of incidents so that the results would be statistically significant.

I'm sure I'm vastly oversimplifying, but only after all of the above were done would the study mean anything. This is also why it takes work to determine if you can believe someone when they say "Studies have shown....". There are a lot of BS "studies" that prove absolutely nothing.

Controlled scientific experiments are one thing. Statistical studies of data, especially of data collected for reasons unrelated (or only weakly related) to the purpose of the study, are a whole different kettle of fish.

ItsJustMe

Whenever I am talking to someone who complains about cyclists riding two abreast, and explain both the law regarding that being legal and the law regarding sufficient passing space, and point out that if they are giving the proper space when passing in the first place, it doesn't matter at all to a car whether the cyclists are one or two abreast, they just get mad at me for pointing out that really they just want cyclists to disappear and stop making them put down their donut and cell phone for 5 seconds.

Daniel4

Protected Bike Lanes. No more getting in the way of cars. No more close passes. No more keeping up with traffic. No more as far right as practical.

Self-driving cars. No more road ragers. No more close passes.