When you drive into a traffic circle, the rule that matters most is simple: yield to any vehicle already going around inside it. Everything else — lane choice, signaling, when to exit — builds on that one idea. Modern roundabouts are engineered to keep speeds low and traffic moving, but only if every driver approaches them the same way.
Yield Before You Enter
Every approach to a roundabout has a yield sign and a dashed yield line painted across the pavement. As you reach that line, slow down and look to your left for vehicles already circulating. If the gap in traffic is wide enough that you can merge in without forcing anyone inside the circle to brake, go. If it isn’t, stop at the line and wait.
An entering driver who causes a circulating vehicle to slow or swerve has violated the right-of-way rule. In a collision between an entering car and a circulating car, the entering driver is almost always found at fault. Failure to yield when entering a roundabout typically results in a traffic citation, points on your driving record, and a fine that varies by state.
Speeds inside a modern roundabout are low by design, generally 15 to 25 mph, because the tight curve forces drivers to slow down.1Federal Highway Administration. Roundabouts Save Lives Yellow advisory speed signs are often posted on the approach. Ignoring a posted advisory speed can contribute to a finding of negligence if something goes wrong.
Pick Your Lane Before You Reach the Yield Line
At a multi-lane roundabout, choosing the correct lane on the approach is the single most important thing you can do to avoid a conflict inside the circle. Signs and pavement markings tell you which lane serves which exit. The general pattern:
- The right lane handles right turns and straight-through movements.
- The left lane handles left turns and U-turns.
That pattern isn’t universal. Markings vary by location, so follow the arrows painted on the road in front of you rather than a rule of thumb. The federal Manual on Uniform Traffic Control Devices allows agencies to place lane-use arrows on the approach and inside the circulating roadway itself.2Federal Highway Administration. 2009 Edition Chapter 3C – Roundabout Markings Those arrows are binding traffic control devices. Entering in the wrong lane and then cutting across to reach your exit is a common cause of sideswipe crashes and can bring an improper-lane-use citation.
Inside the Circle: Stay in Your Lane
Once you’re circulating, do not change lanes. The geometry is tight, sight lines are short, and drivers in adjacent lanes are focused on their own exit rather than on someone drifting sideways. A driver who starts a lane change inside the circle and clips another vehicle will generally be found at fault for the sideswipe.
If you realize mid-circle that you’re in the wrong lane for your exit, don’t try to fix it by cutting over. Take whichever exit your lane directs you to, then reroute from there.
If You Miss Your Exit
Just keep driving around and take it the next time. There’s no penalty and no law broken. Never stop, back up, or reverse direction inside a roundabout. Going the wrong way in a circular intersection creates a head-on risk in a space where every other driver expects traffic to flow one way. Going around again is both the legal option and the safe one.
Signal When You Exit
The habit to build is signaling your exit, not your entry. The timing most state transportation departments recommend: activate your right-turn signal as you pass the exit just before the one you plan to take. That gives waiting drivers at the next entry a clear cue that you’re leaving the circle and they can prepare to move.
- Taking the first exit (a right turn): signal right as you approach the yield line.
- Going straight through or turning left: enter without signaling, then signal right once you pass the exit before yours.
Failing to signal when exiting can result in a citation under the general turn-signal requirement that exists in every state.
Sharing the Circle
Pedestrians
Roundabouts place marked crosswalks on each approach leg, set back roughly 25 feet from the yield line at single-lane designs and up to 50 or 75 feet back at multi-lane designs.3Federal Highway Administration. Roundabouts – An Informational Guide, Chapter 6 Geometric Design The setback separates the decision to yield to a pedestrian from the decision to yield to circulating traffic, so you’re not processing both at once.4Federal Highway Administration. Roundabouts with Pedestrians and Bicycles Splitter islands in the middle of each leg give pedestrians a refuge, letting them cross one direction of traffic at a time. You must yield to pedestrians in these crosswalks just as at any other marked crossing.
Cyclists
Cyclists are legally allowed to ride through a roundabout as vehicles. At single-lane roundabouts they’re encouraged to take the center of the lane, and shared-lane markings and “Bicycles Allowed Use of Full Lane” signs reinforce that. Don’t try to pass a cyclist inside a roundabout. The circle is too short and too tight for a safe pass, and the cyclist will be exiting shortly. Give them the same space you would give another car.
Large Vehicles and Truck Aprons
Semi-trucks, buses, and vehicles towing trailers need more room than the circulating lanes provide. At a multi-lane roundabout, a large truck may straddle both lanes to make it through the curve. Don’t try to squeeze past it.
Many roundabouts also include a truck apron, a raised, textured strip of pavement between the central island and the travel lane. It’s designed to be mountable by the rear wheels of a long trailer but uncomfortable enough to discourage passenger cars from using it.3Federal Highway Administration. Roundabouts – An Informational Guide, Chapter 6 Geometric Design Truck aprons are often colored or textured concrete and sit slightly higher than the road surface. In a regular car, stay off the apron.
Emergency Vehicles
If you hear a siren or see flashing lights while you’re circulating, do not stop inside the circle. Continue to your nearest exit, pull off to the right, and stop to let the emergency vehicle pass.5Federal Highway Administration. Roundabouts and First Responders Stopping inside the roundabout blocks the emergency vehicle and every other driver trying to clear out of the way.
If you haven’t yet entered when you notice the emergency vehicle, stay at the yield line and wait. Let it pass through the circle before you proceed.
A Note on Older Rotaries
People use “traffic circle,” “roundabout,” and “rotary” interchangeably, but transportation engineers treat them as different designs. Older rotaries, common in the Northeast, were built with diameters of 300 feet or more and allowed vehicles to enter at highway-like speeds. Some placed stop signs or traffic signals inside the circle, and a few gave entering traffic the right of way over circulating vehicles.1Federal Highway Administration. Roundabouts Save Lives
The advice above applies to modern roundabouts, which is what nearly every newly built circular intersection is. If you encounter an older rotary with traffic signals or signs inside the circle, follow whatever those devices tell you. When no such devices exist, the default rule is the same everywhere: yield to circulating traffic before you enter, stay in your lane, and signal your exit.