Roundabouts
Some content adapted from information supplied by the NYS Department of Transportation 
A roundabout is a type of intersection control, just as signals and stop signs are examples of intersection control. A roundabout is a circular intersection with a center island where traffic moves counter-clockwise around the center island.
Roundabouts are Different from Traffic Circles
A roundabout is not the same as the older-style rotary or traffic circle.
In New York State, the right of way rule for a rotary or traffic circle is the same as the rule for a roundabout. Traffic about to enter the circle or rotary must yield to traffic that is in the rotary or circle.
A roundabout normally has all of the following:
- Yield entries - require that a driver about to enter the roundabout must wait for a gap in the traffic inside the roundabout before they enter the roundabout.
- Traffic islands that separate the entries of the roundabout from the exits.
- Designated crossing areas for pedestrians.
- Designated speeds of 15 - 20 miles per hour.
Driver Opinions of Roundabouts
At first drivers can feel anxious and uncomfortable about using roundabouts. Until they get experience with roundabouts, drivers prefer traditional intersections with traffic lights and stop signs. When drivers get experience in using roundabouts, they become more comfortable with them and most drivers come to prefer roundabouts.
Efficiency
Roundabouts can handle traffic more efficiently than traditional intersections. Roundabouts help to maintain a continuous flow of traffic. Drivers need not wait at a traffic light if there is no traffic to interfere with their movement. More vehicles can move through the intersection with less delay.
The one-way traffic design of roundabouts makes it easier for large vehicles like trucks and buses, to turn.
Safety
Roundabouts are statistically safer than both traffic circles and traditional intersections. Collisions that occur in roundabouts are normally less severe than collisions in traditional intersections. Less severe crashes at lower speeds are even more important to older drivers than to drivers in other age groups.
A study compared traffic crashes in roundabouts in the U.S. with crashes in the traditional intersections that were replaced by the roundabouts. There were 40% fewer vehicle collisions, 80% fewer total injuries and 90% fewer serious injuries and fatalities in the roundabouts.
At intersections with stop signs or traffic lights, the most common and serious crashes are right-angle, left-turn, or head-on collisions. These collisions are more severe because of the angle of the impact and the speed of the vehicles.
These types of severe crashes rarely occur in roundabouts because in a roundabout:
- Vehicles interact as they travel in the same direction.
- Roundabouts do not have traffic signals. There is no need for a driver to increase speed to enter the intersection before the signal changes.
- Speed is controlled by the curve of the roadway. Drivers normally follow the rules and slow down when they enter a roundabout.
For these reasons, the few collisions that occur in roundabouts are normally less serious, with few injuries.
Pedestrians can find that crossing in a roundabout is also safer for them because:
- Vehicles are moving at slower speeds than in traditional intersections.
- Traffic will approach a crossing pedestrian from only one direction at a time.
- Since pedestrians cross in two movements using the median refuge, the time to cross and the exposure to traffic are much less.
A bicyclist can ride in the travel lane(s) of the roundabout or walk the bicycle through the crosswalks. It can be safer for a rider with less experience to walk and use the pedestrian crosswalks to get through the roundabout. Some roundabout designs have a ramp from the roadway shoulder to the sidewalk. This ramp can make it easier for a bicyclist to use the sidewalk option of a roundabout.
When an emergency vehicle approaches a typical intersection, a driver normally gets out of the intersection as quickly as possible. The driver then pulls to the right side of the road and stops until the emergency vehicle has passed.
The procedure is the same in a roundabout. If you are in the circle when an emergency vehicle approaches the roundabout with lights or sirens on:
- Do no stop inside the roundabout.
- Continue to your exit.
- When you are outside the roundabout, pull over to the right side of the road and stop.
If you are not yet in the roundabout and there is enough space for the emergency vehicle to go by your vehicle, pull over and stop before you enter the roundabout. If you determine that there is not enough space, enter the roundabout, and exit the roundabout. Then pull over to the right and stop.
How to Drive through a Roundabout Intersection
As you approach a roundabout, there will be a YIELD sign. Slow down, stop for any pedestrians or bicyclists in the crosswalk. Also be prepared to stop for any traffic already in the roundabout.
As you approach a roundabout with two or more traffic lanes, look for pavement markings and traffic signs that direct you to the correct lane for the road or turn you want to take.
Get in the correct traffic lane early. You can normally use the right traffic lane (shown in blue below) to go right and straight through the roundabout. You can normally use the left lane (shown in red below).to go straight, to go left around the center island, or to make a U-turn.
IMPORTANT: You CANNOT go left from the right lane (blue). It results in a conflict with the traffic in the left lane (red) and can cause a crash.
At the YIELD sign, yield to all traffic (in both lanes) that approaches from the left in the circle. However, do not stop if the way is clear.
This is not a merge situation, you must stop for all traffic already in the roundabout. At a multilane roundabout, you must yield even if you will only use the right lane and the first exit from the roundabout.
Never pass other vehicles or change traffic lanes in the roundabout.
Traffic in a roundabout always goes counter-clockwise. The roundabout has ONE WAY traffic signs mounted in the center island. The signs help to guide traffic and indicate that the driver must stay to the right of the center island.
Give large, long vehicles, like tractor trailers, the space to use both traffic lanes throughout the roundabout, including approaches to, and exits from the roundabout.
