You'll often hear that cyclists shouldn't ride two abreast – it's a classic for angry people on social media – but what does the law say and when is it appropriate? Here's what you need to know.
We reported on road.cc a few years ago that a police officer in Essex had pulled over a couple of cyclists and insisted they were breaking the law by not riding in single file. The cyclists were told, "You are causing other road users to drive carelessly."
Even after consulting a copy of The Highway Code, the officer insisted that the cyclists were endangering themselves and other road users by riding side by side, and took down their details.
Let's see what The Highway Code says.
Rule 66 states: "You should... never ride more than two abreast, and ride in single file on narrow or busy roads and when riding round bends."
Side-by-side cycling isn't prohibited, then.
What constitutes a 'narrow or busy road'? How many degrees are there in a bend? Sorry, none of that is defined.
The Highway Code is clear, though, in making a distinction between rules that use the words 'must/must not', which are legal requirements, and rules that use wording such as 'should/should not' or do/do not', which are advisory.
The instructions not to ride more than two abreast, and to ride in single file in certain circumstances are advisory. You can ignore the advice, then? It's worth bearing in mind that according to The Highway Code, "Although failure to comply with [advisory] rules of the Code will not, in itself, cause a person to be prosecuted, The Highway Code may be used in evidence in any court proceedings under the Traffic Acts to establish liability".
Riding two abreast can be the sociable choice, of course, in that it allows you to chat easily with other riders rather than shouting forwards and backwards along a line. That's a big part of cycling's attraction for many people.
You might see comments from armchair experts saying that the road isn't the place for going out and being sociable. That might be their opinion but it certainly isn't a rule you'll find in The Highway Code... not even an advisory one.
Riding side by side can improve your safety too. It allows you to be seen more easily by other road users, both ahead and behind (see our article Why don't cyclists stick to the left of the lane? for more on visibility in different road positions).
It also helps motorists in many circumstances by shortening the distance required for overtaking. Cyclists riding side by side take up about half the road length of cyclists riding in a single line (the example figures of 4m and 8m shown in our illustrations are dependent on how closely each cyclist follows the wheel in front, of course).
'Close pass' initiatives make it clear that motorists should always give cyclists clearance of at least 1.5m when coming by. This virtually always means moving on to the opposite side of the road, at least partially, so overtaking when traffic is coming in the other direction isn't an option. With that in mind, riding two abreast doesn't generally prevent overtaking when it would otherwise be safe and reasonable, although it might stop motorists squeezing past when there's not enough space.
In his cycling skills manual Cyclecraft – which forms the foundation of Bikeability, the UK's national standard for cycle training – John Franklin says, "If the road situation is such that it would be unsafe for traffic to pass cyclists riding in single file, 10 riding two abreast can help dissuade following drivers from doing so."
John Franklin also advises, "The longer the riding group, the more difficult it will be for other vehicles to overtake and the more likely they will be to cut in between riders. For these reasons, groups should divide, as necessary, into sub-groups about five riders long, with a gap of at least 20m between sub-groups. This allows traffic to overtake one sub-group at a time."
As mentioned above, The Highway Code says that cyclists should "ride in single file on narrow or busy roads and when riding round bends", but it doesn't define those terms.
You need to use your own judgment here, and that develops with experience. You'll probably consider it appropriate to move to single file if traffic is getting held up behind you and it's safe to let it overtake.
This video with Chris Boardman makes things clear...
Mat has been in cycling media since 1996, on titles including BikeRadar, Total Bike, Total Mountain Bike, What Mountain Bike and Mountain Biking UK, and he has been editor of 220 Triathlon and Cycling Plus. Mat has been road.cc technical editor for over a decade, testing bikes, fettling the latest kit, and trying out the most up-to-the-minute clothing. We send him off around the world to get all the news from launches and shows too. He has won his category in Ironman UK 70.3 and finished on the podium in both marathons he has run. Mat is a Cambridge graduate who did a post-grad in magazine journalism, and he is a winner of the Cycling Media Award for Specialist Online Writer. Now over 50, he's riding road and gravel bikes most days for fun and fitness rather than training for competitions.