A roundabout is an intersection where traffic flows in a counter clockwise direction around a centre island. When you approach a roundabout you must wait for pedestrians to cross and wait for a safe gap in traffic already in the circle before you enter the circle. Traffic inside the roundabout has the right-of-way. That means that if you are in the roundabout, you do NOT stop to let other vehicles enter.
Roundabouts are designed to reduce traffic delays because you do NOT have to stop before entering a roundabout unless there is a vehicle or pedestrian in your way.
Roundabouts also reduce collisions because there are fewer points in the roundabout where vehicles can come into contact with one another.
Slower speeds in roundabouts mean that any collisions that do happen will be less severe.
Speeds are slower in roundabouts because you must turn right to enter the roundabout, turn left to go around the centre island, and turn right to exit the roundabout. All this turning means that you must slow down but you do not necessarily have to stop. Once you are in the roundabout, all traffic is moving in the same direction so traffic flows more smoothly.
Because roundabouts keep traffic flowing, you may use less fuel. This can lead to better air quality because there is less vehicle-related pollution.
Roundabouts may have one or more lanes.
When you approach a roundabout, do these 3 things:
Once you are in the roundabout, follow the traffic signs and road markings to your exit. Do NOT stop to let other vehicles enter.
Roundabouts were developed in the United Kingdom (UK) in the 1960s and now are widely used in many countries. You can expect to see increasing numbers of roundabouts across Canada and the United States.
No. The most important thing to remember about roundabouts is that you must wait for a safe gap in traffic before entering. Once you are in the roundabout you do NOT stop to let other vehicles enter.
You may have had bad experiences with large, old-style traffic circles (also known as "rotaries") such as the Mic Mac Rotary.
Old-style traffic circles were bigger than modern roundabouts. Traffic moved at higher speeds. Drivers were expected to merge and weave their way through. As a result, drivers were often nervous when they had to enter the traffic circle. They had good reason to be. Traffic circles had high collision rates. If roundabouts are new to you, you may think you will have the same issues since they are also circular intersections.
Some ways roundabouts are different from rotaries and traffic circles
The features listed above make entering roundabouts easier than entering traffic circles as most traffic circles do NOT have these features. In addition, traffic circles are unpredictable as different traffic circles have different kinds of entry points.
When you see the following features, you know you are driving on a well-designed roundabout:
All of these features work together to get drivers to slow down and look for a safe gap in traffic.
The design features of a good roundabout improve traffic flow and safety.
Roads leading to roundabouts should curve far enough ahead of the roundabouts to get drivers to slow down.
Traffic islands that separate entrance and exit lanes are called splitter islands. These should extend from the edge of the roundabout into the approaching road. This allows for pedestrian crossings where drivers need look only for pedestrians and not competing traffic.
Traffic signs, road markings, and lighting should warn drivers that they are coming to a roundabout and that they should slow down. With multi-lane roundabouts, signs and lane markings should help drivers choose the lanes they need to enter and exit the roundabout.
Nova Scotia is currently using resources from BC, Alberta, Quebec, Ontario, Florida, and the UK as well as our own experience to help design our roundabouts. In the future we will use the Canadian Roundabout Design Guide as our major resource.
Roundabouts may seem bigger than traditional intersections but they take up about the same amount of space. Since you must turn right to enter a roundabout, there is no need to widen roads to make room for right-turn-only or left-turn-only lanes.
Sometimes, roundabouts need more space than simple intersections controlled by stop signs or traffic signals because the road has to go around a centre island. But the roads leading to roundabouts usually need fewer lanes and so take up less space.
Roundabouts may need more space than traditional intersections. Many factors determine the size of a roundabout. These include the following:
No. Different traffic conditions call for different solutions. Roundabouts are only one tool in the road planning toolbox.
Engineers study one intersection at a time to decide whether a roundabout is right for that particular area. They look at where and how the roads come together as well as traffic conditions before coming up with the best solution for that intersection.
These are some of the reasons engineers would choose a roundabout over a traditional intersection:
These are some other good places for roundabouts:
Roundabouts are NOT the best choice everywhere. These are some areas where traditional intersections may be a better choice:
Yes. Most Nova Scotia roundabouts are designed to handle a standard 53-foot tractor-trailer.
Roundabouts are designed to handle trucks, buses, tractors, and larger vehicles. They do this using a "truck over-run area". This is a slightly raised area around the centre island. The rear wheels of a truck can roll safely over this area making it easy for larger trucks to drive in the roundabout.
A truck over run area lets large trucks go through the roundabout easily and at the same time prevents smaller cars from going too fast.
When you come to a roundabout, you must wait for a safe gap in traffic before entering. Most vehicles come to a rolling stop-if they stop at all-then go slowly through the roundabout. As the driver of a large vehicle, take care to stay close to the left side of the lane when you enter and leave the roundabout. You should be able to drive a standard 53-foot tractor-trailer through most Nova Scotia roundabouts without riding over the curb as long as you go slowly.
Trucks need more space to turn than cars do. When using roundabouts, large trucks need to use all the available space. This means that in multi-lane roundabouts, trucks will have to cross lanes. Roundabouts are designed to allow for this.
Roundabouts are good for trucking because they cut down on delays, idling, and the need for hard breaking and acceleration.
In a traditional intersection with traffic lights, you would have to stop for the red lights, idle your engine and wait. When it is your turn to go, you would have to accelerate from a stopped position to drive through the intersection. The wear on braking systems, fuel consumption, and lost time due to red lights can add up if an intersection is on a haul route.
Yes. Roundabouts add green space wherever they are built and fewer traffic delays mean less air pollution.
Some ways roundabouts are better for the environment:
Studies have found that replacing a traditional intersection with a roundabout can cut green house gas emissions and that drivers can save fuel.
The main benefits of roundabouts are the following:
More ways roundabouts are good things:
Yes. Roundabouts have more green space and less asphalt than traditional intersections. Planners and designers have more freedom to beautify these green spaces safely and at low cost.
Many communities use the centre island of a roundabout to welcome travellers. Designers can plant trees, shrubs, and flowerbeds, or install sculptures or other artwork to make the centre island attractive. Centre islands are safe spaces for gardens and art because pedestrians are NOT meant to use them. Landscaping should NOT encourage pedestrians to explore the centre island.
Yes. Whatever is placed in the centre of the roundabout is put there to get you to look left. You need to look left, rather than across the circle, to find a safe gap in traffic before you enter the circle.
The landscaping in the centre of a roundabout is, first and foremost, a safety feature. It is there to get you to look left in the direction of oncoming traffic. Good landscaping will block your view across the circle so that you are not distracted by activity there. Instead, you are forced to look left before you enter the circle.
Limiting vision in this way gets you to slow down and watch for a safe gap in traffic before you enter the circle.
Roundabouts are new to North America. The switch from traditional intersections to roundabouts began in the 1990s. People are slowly getting used to them, but some still need convincing.
People are creatures of habit. When we are used to doing something one way, we often resist change. Sometimes we can only see the benefit of the change AFTER the change has been made.
Transportation agencies have been installing traffic signals for a long time. It's normal that changing this practice will take a while.
Some drivers and elected officials still need to be convinced that roundabouts are safer and better for the environment than traditional intersections.
What we know is that more people like roundabouts AFTER they use them than when they are proposed.
A study of 6 communities in the US shows this to be true. In the first 3 communities people were asked their opinion of roundabouts before and after they were built. Before the roundabouts were built, only a third of the drivers supported the roundabouts. After they were built, support doubled. A study of 3 more communities had similar results. Just over a third of drivers supported roundabouts before they were built but support jumped to half the drivers after they were built.
About a year after these roundabouts were built, drivers were asked for their opinions again in all 6 communities. This time, 7 out of every 10 drivers supported the roundabouts.
There are thousands of roundabouts in North America. There are about 300 in Canada.
Nevada was the first state to build roundabouts. It began building them in 1990. Soon after, in the late 1990s, Quebec began to build roundabouts. Since then, about 3,000 roundabouts have been built in the US and about 300 in Canada. By comparison, there are about 15,000 roundabouts in Australia, 20,000 in the United Kingdom, and 30,000 in France.
Traditional intersections and roundabouts cost about the same amount to build.
Every intersection is different.
Here are some things that make any intersection more expensive:
Roundabouts use less electricity because it is only used to light the area at night. Some intersections need electricity to power traffic lights.
There are fewer serious collisions in roundabouts and that saves money on healthcare and related costs.
Roundabouts may or may not use more land depending on the number of turn lanes needed for a traditional intersection.
Traffic in the roundabout has the right-of-way. You must wait for a safe gap in traffic before you enter the roundabout.
There are a number of things you must do when you use a roundabout:
Slow down. Roundabouts are designed for speeds of between 30 and 50km/h. Look for signs that will help you to find your exit. Watch for people using the crosswalk and be ready to yield or stop.
Some roundabouts have 2 or more lanes. Follow the signs and road markings to choose the correct lane before you enter the circle. On multi-lane roundabouts, the lane you use to enter the roundabout determines where you can exit.
Remember to yield to ALL lanes of traffic in a multi-lane roundabout.
There are 2 places to yield when approaching a roundabout:
Enter the roundabout when there is a safe gap in traffic. Continue until you reach your exit. Stay in your lane at all times. Do NOT stop except to avoid a collision.
Never drive next to a large vehicle or truck on a multi-lane roundabout and don't try to pass one. Large trucks need a lot of room to turn. You can give them the room they need by staying farther behind them than you normally would with passenger vehicles.
As you near your exit, use your right-turn signal to let others know you plan to exit.
Exit at a slow speed. Watch for people using the crosswalk and be ready to stop. If you miss your exit, keep going around the roundabout until you reach it again.
Emergency vehicles with flashing lights and sirens ALWAYS have the right-of-way. In a roundabout, that means giving the whole roundabout to the emergency vehicle. There are 2 possibilities:
Do NOT stop in the roundabout as you might block the emergency vehicle's path.
Slow down and take your time. If possible, practise driving in the roundabout when traffic is lighter. That way, you will be better prepared to use it in heavier traffic.
Using a roundabout is a lot like making a right turn from a stop sign or traffic light. In that case, you signal your intent to turn, stop at the stop bar, watch for a safe gap in traffic coming from the left, and then turn right onto the cross street.
In a roundabout, you yield to traffic in the roundabout at the yield line. That means you look left for a safe gap in traffic, and drive into the roundabout when the way is clear. Once you are in the roundabout, follow the road until you reach your exit. Signal your intent to exit and continue on to your destination.
Remember to watch for pedestrians and cyclists in the crosswalks.
If the thought of driving in a roundabout makes you nervous, take some time to practise during off-peak hours or whenever traffic is lighter. This way you can get used to driving in the roundabout. The more you practise, the more comfortable you will be driving in the roundabout.
Because of the low speeds, your risk of being in a collision or getting hurt is lower than it is in a traditional intersection.
If you know the rules of the road, pay attention to those around you, and slow down you will do well.
As roundabouts become more common you will get used to how they work. The more you use roundabouts, the more confident you will become.
Studies of roundabouts in the US suggest that they are safer for older drivers than traditional intersections.
In fact, traditional intersections can be more challenging for seniors who are coping with vision loss, hearing loss, trouble thinking, or other physical impairments.
When older drivers are involved in collisions at intersections, it is often because they fail to yield the right-of-way. This is particularly true when they turn left or enter busy roads from side streets. These problems do not exist in roundabouts.
Many seniors like roundabouts. A 2007 study in 6 communities where roundabouts replaced traditional intersections found that about 2 thirds of drivers aged 65 and older supported the roundabouts.
Roundabout ahead. Slow down.
Yield to all traffic in the roundabout including pedestrians at the crosswalk. "Yield' means wait for a safe gap in traffic. You may have to stop. Traffic in the roundabout always has the right-of-way.
Follow the direction of the chevrons. Drive one way, counter-clockwise around the roundabout.
Roundabouts can handle as much traffic as they need to. They are designed to be the right size with the right number of lanes to handle the traffic.
Many people, even some traffic engineers, don't realize how many vehicles can go through a well-designed roundabout. Most roundabouts can handle more traffic with fewer delays than intersections with traffic lights.
Single-lane roundabouts can handle up to 30,000 vehicles a day. They can handle more vehicles than 4-way stop intersections. Roundabouts have fewer and shorter delays than both 4-way stop intersections and intersections with traffic lights. Roundabouts with more than one lane can handle even more traffic.
There are fewer and shorter delays because traffic flows slowly, continuously, and all exits are right turns.
Roundabouts change how traffic flows in an area. Because there are no red lights or stop signs, vehicles can go through without stopping as long as the way is clear. Roundabouts don't 'create' traffic; they just handle it differently.
The goal of a roundabout is to let traffic flow efficiently and continuously. This does not necessarily mean that traffic will increase.
Traditional intersections, particularly those with stoplights, produce stop-and-go traffic patterns. Large numbers of vehicles line up at a red light and move together when the light turns green. This means there is a large gap in traffic downstream when the light is red, but few gaps when the light is green. Joining the flow from a side street or driveway can be difficult.
Roundabouts create a steady flow of traffic with frequent, smaller gaps. These gaps are not predictable, as they are at intersections with traffic lights. They do, however, create more frequent opportunities for drivers to turn out of driveways and side streets.
Here's how it works:
Traffic already in the roundabout has the right-of-way. That means anyone who wants to enter the roundabout must wait for a safe gap in traffic. When vehicles leave the roundabout, they will use different exits. This means that there is NOT a constant flow of traffic leaving the roundabout in any one direction.
When a vehicle leaves the roundabout on a different road than the one a driver waiting to turn onto from a driveway or side street wants to use, there is a gap that that driver can use to enter the flow of traffic. Slower traffic caused by the roundabout also helps drivers turning from driveways or side streets.
Sometimes a large amount of traffic and certain turning patterns can create problems downstream from the roundabout. But these problems would also happen where there is an intersection with a traffic light. At intersections, traffic turning right and left from the cross street tends to fill the gaps between large strings of through traffic.
Snowplows can clear roundabouts just as easily as they do other roads and intersections.
Give snowplows the right-of-way in the roundabout. If you see a snowplow enter the roundabout ahead of you, wait until the plow has finished clearing the roundabout and exited before you enter.
Drivers have to slow down to use a roundabout. Slower cars mean safer intersections.
These are some things that make roundabouts safer than other intersections:
Roundabouts are designed to slow traffic. Slower speeds give everyone more time to fix their mistakes. Collisions that occur at slower speeds are less harmful than those that occur when people drive faster.
There's one main rule: wait for a safe gap in traffic before you enter the roundabout. When you come to a roundabout, the road and signs will prompt you to slow down. As you near the crosswalk, you can see if you need to wait for someone to cross. That person is the only thing to watch for at this point. Once you cross the crosswalk, the next thing to look for is a safe gap in traffic in the roundabout.
The most harmful collisions are those that occur at high speeds or at sharp angles. Roundabouts are designed for speeds of between 30 and 50km/h. If you obey the rules of the roundabout, it is impossible to be in a right-angle or head-on collision.
Collisions happen at conflict points. Conflict points are places where vehicles may hit each other or pedestrians. There are 32 vehicle-to-vehicle conflict points and 24 vehicle-to-pedestrian conflict points at any traditional intersection. That's a total of 56 conflict points. Roundabouts, on the other hand, have 8 vehicle-to-vehicle conflict points and 8 vehicle-to-pedestrian conflict points for a total of 16. This means there are 40 fewer potential crashes wherever roundabouts are built.
According to Transport Canada, there are about 2,500 deaths and 145,000 injuries caused by collisions each year.
Studies done in Europe, New Zealand, the US, and Canada all show that there are fewer injuries caused by collisions in roundabouts than in traditional intersections - up to 74 per cent fewer. These studies also show that injuries caused by collisions in roundabouts are less severe than those that occur at traditional intersections.
That's why Transport Canada recommends changing traditional intersections to roundabouts.
Two things make crossing at roundabouts safer than crossing at traditional intersections:
When you cross at a traditional intersection, you need to look for vehicles in 3 directions: your left, your right, and over your shoulder for vehicles turning right. You also have to watch for drivers running red lights. Drivers running red lights can kill you because they tend to speed.
You are often safer crossing at a roundabout because you only have to watch for traffic coming from one direction at a time. Also, traffic is usually moving more slowly.
Because of this, you are less likely to get hit at a roundabout than at a traditional intersection. Also, there are fewer places for a vehicle to hit you in a roundabout because there are fewer conflict points. If a vehicle does hit you, your injuries will likely be less serious because traffic is slower in roundabouts.
Since you and the driver both have to decide when to go, you are likely to watch for each other more carefully.
As with all intersections, you need to know when vehicles are stopped so you can cross safely. Technologies are being tested across North America to improve crossing for everyone.
The North American transportation community is currently studying how to make roundabouts safer for the visually impaired. Some countries, like the United Kingdom, use crosswalk signals. We are also looking at using tactile surfaces, defined walkway edges, and added lighting.
Yes. Cyclists can ride or walk their bikes through roundabouts.
Because roundabouts are designed for speeds of between 30 and 50km/h, you should be able to ride your bike at nearly the same speed as the vehicles around you. As a cyclist, you can choose to ride on the road, as a vehicle, or use the sidewalk around the roundabout.
When you ride on the road, stay near the middle of the lane so that drivers can see you and will not try to pass you. This is called "claiming the lane." Vehicles should be going about the same speed as you in the roundabout.
If you choose to use the sidewalk around the roundabout, get off your bike and walk on the sidewalk and in crosswalks. Pedestrians have the right-of-way here. Some roundabouts have multi-use trails around them. To use these, you may have to get off your bike to cross a sidewalk or use a crosswalk.
Rear-end collisions are the most common collisions to occur at roundabouts. These are often caused by drivers failing to wait for a safe gap in traffic, or choosing the wrong lane and changing lanes at the wrong time. Still, collisions in roundabouts are less severe than those in other places because of the slower speeds.
Despite the safety benefits of roundabouts, some collisions still occur.
There are 2 kinds of collisions that are more common at single-lane roundabouts: rear-end collisions and entering collisions.
Rear end collisions occur when a vehicle hits the back of another vehicle. This usually happens at the entrance to the roundabout.
Entering collisions occur when a vehicle entering the roundabout does not wait for a safe gap in traffic and hits a vehicle already in the roundabout. These kinds of collision are generally only minor "fender benders." In contrast, head-on and turning collisions that occur at traditional intersections can lead to serious injury or death.
At multilane roundabouts the 2 most common kinds of collisions are "failure to yield" and "improper lane selection".
"Failure to yield" is another way of saying, "did not wait for a safe gap in traffic." In multi-lane roundabouts you must be sure that all lanes are clear before you enter the roundabout. This includes the inside lane. Vehicles in the inside lane will NOT stay there. They will have to leave the roundabout, which means they could move in front of the entering vehicle. This kind of collision is the entering vehicle's fault because it failed to wait for a safe gap in traffic.
Improper lane selection means a driver chose the wrong lane to enter the roundabout. This means the driver has to change lanes quickly inside the roundabout. This happens most frequently near the exit. There are 2 reasons for this:
It is illegal to cause a collision by changing lanes quickly without warning nearby drivers. This is true on all roads, not just roundabouts.
Going too fast in a roundabout can also cause a collision. Some drivers approach the roundabout too quickly to slow down enough to turn into the roundabout or to wait for a safe gap in traffic.
Most roundabouts are designed to warn drivers to slow down in plenty of time. These are some of the warning features: