Safety & Rules
Roundabouts Are Where Riders and Drivers Read the Road Differently
A roundabout asks every user to judge gaps, speeds and exits at once. Cyclists are the smallest and least expected participants in that judgement.
The points below about roundabout riding are ordered by how much difference they make, not by how often they get repeated.
What matters most
- Being passed inside a roundabout is the main hazard.
- Central positioning prevents overtakes that end in a turn across you.
- Entry rules and lane conventions vary between countries.
Why roundabouts are difficult
A roundabout requires you to judge approaching vehicles, choose a gap, position for an exit and monitor other users simultaneously. Drivers doing the same are scanning for vehicle-sized gaps and vehicle-sized threats, which is not what a cyclist presents.
Cyclists are also slower to accelerate into a gap, so a gap that looked adequate can close during entry. The greatest risk is a vehicle passing you within the roundabout and then leaving at the exit you are riding past. Multi-lane roundabouts multiply all of this, since vehicles change lanes within the circulation as well.
Position on approach and inside
Riding towards the centre of your lane on approach prevents a vehicle from entering the roundabout alongside you. Holding that position within the circulation prevents an overtake that would end with the vehicle turning across your path.
Riding near the outer edge invites vehicles to pass on your right or left depending on the country's direction of travel, which is precisely the conflict to avoid. This feels assertive and is the standard advice in cycle training in several countries for exactly this reason. Return to a normal position once you have left the roundabout, which keeps the interaction cooperative.
Choosing and taking a gap
Accept a larger gap than a driver would, because your acceleration is lower and your speed within the roundabout will be too. Look at the approaching vehicles' speed rather than their distance, since a fast approach closes a gap quickly. Waiting is free, and being pressured into a marginal gap by a queue behind you is how riders get into trouble.
Mid-traffic, if the roundabout is genuinely too busy or too fast, using a pedestrian crossing on foot is a legitimate choice. There is no obligation to ride something that feels beyond your judgement on a given day.
Signalling within a roundabout
Signal your exit as you pass the one before it, which is when the signal is most informative to waiting drivers. Do not signal on entry in a way that suggests you are leaving at the first exit unless you are.
The bit that actually matters: return your hand to the bars before actually exiting, since you need control more than continued signalling. Look over your shoulder before moving towards an exit, because a vehicle may already be beside you. Conventions on signalling within roundabouts differ between countries, so learn the local expectation.
Cycle infrastructure at roundabouts
Some countries build separated cycle tracks around roundabouts, with priority rules that vary considerably between designs. Where such tracks exist, whether cyclists have priority over exiting traffic is a design decision with real safety consequences. Painted lanes around the outside of a roundabout are generally considered poor practice, since they place riders exactly where vehicles cross.
Turbo and multi-lane designs are particularly hostile to cyclists riding on the carriageway. Where the design is bad and the traffic is heavy, dismounting and using crossings is a reasonable and unglamorous answer.
Large vehicles specifically
Lorries and buses swing wide and their trailers cut in, so the space beside a large vehicle changes shape as it turns. Never enter a roundabout alongside a large vehicle, and never remain beside one within the circulation.
By the second week of riding, if a large vehicle is entering behind you, consider waiting rather than sharing the roundabout with it. Hanging back and letting it go is a few seconds lost against a category of collision that is frequently fatal. This is the one situation where being slow is unambiguously the right decision.
Everything above, in order of what to do first
- Why roundabouts are difficult. A roundabout requires you to judge approaching vehicles, choose a gap, position for an exit and monitor other users simultaneously.
- Position on approach and inside. Riding towards the centre of your lane on approach prevents a vehicle from entering the roundabout alongside you.
- Choosing and taking a gap. Accept a larger gap than a driver would, because your acceleration is lower and your speed within the roundabout will be too.
- Signalling within a roundabout. Signal your exit as you pass the one before it, which is when the signal is most informative to waiting drivers.
- Cycle infrastructure at roundabouts. Some countries build separated cycle tracks around roundabouts, with priority rules that vary considerably between designs.
- Large vehicles specifically. Lorries and buses swing wide and their trailers cut in, so the space beside a large vehicle changes shape as it turns.
The takeaway
Take the lane, take a bigger gap than a driver would, and never share a roundabout with a lorry.
Most of riding well is being boring and predictable to everyone else on the road.
Questions readers ask
Where should I ride on a roundabout?
Towards the centre of your lane, both on approach and within the circulation, so vehicles cannot pass you and then exit across your path. Move back to a normal position after leaving.
Is it acceptable to walk around a busy roundabout?
Entirely. Using pedestrian crossings on foot is a legitimate choice when traffic speed or volume makes riding it feel beyond your judgement.
