How do roundabouts help traffic

Find out more about why roads are built and how they help us get around the country with Dan and Bex! Roundabouts in the playground are lots of fun, but the roundabouts we drive around on the roads are a clever way to manage traffic at intersections where roads meet. They help everyone get where they need to go safely, and often much more quickly than at junctions with traffic lights.

Roundabouts are safer for pedestrians too, because unlike at a road junction where traffic may be coming from several different directions, traffic enters and leaves roundabouts in the same direction, making it easier to cross. They also help vehicles use less fuel because they keep traffic moving along as opposed to sitting in queues at lights.

Of course, back then the main form of traffic had four legs and a tail. Unless one asserts some type of driver exceptionalism see incompetence , the evidence that roundabouts safer than traditional signalized or signed intersections is overwhelming. A snapshot regarding previous research from around the world from that report:. In , a before-and-after study was conducted in the Netherlands of roundabouts that were previously stop controlled or signalized intersections.

A before-and-after study of 73 roundabouts in Australia conducted in the year showed a reduction of 74 percent in the casualty i. In , 34 modern roundabouts in Germany were studied. This study found that the number of fatalities and severe injuries decreased from 18 to 2. The number of accidents with heavy property damage decreased from 24 to 3. France studied about 83 roundabouts in the year , and concluded that the transformation of regular intersections into roundabouts yielded significant safety benefits.

While the fatalities reduced by 88 percent, the injuries fell by approximately 78 percent. Another study of roundabouts in the year found that 90 percent of them had no injury accidents at all.

Sixty years later, the maverick traffic engineer Frank Blackmore invented the modern roundabout, where entering vehicles yield to circulating traffic. To help introduce the new idea to motorists, he would park himself on a traffic island in Peterborough and bark instructions at them through a loud-hailer. The UK today boasts 25, roundabouts: the most in the world as a proportion of road space.

France has more in total. The roads themselves, however, are changing. Congestion is greater. Cyclists are more numerous. Accident black-spots are highlighted: an algorithm has ranked roundabouts and junctions according to casualties and injuries. Three roundabouts in the northern Gosforth suburb rank fourth, seventh and 10th worst for injuries caused by moor vehicle collisions.

Roundabouts, he says, cause tailbacks unless the traffic on each approach road is equal. He clicks play on a video of blinking lights that move across another map of the city.

These are cars, captured by number plate recognition. Grant points to large areas that are dark: gaps in his control of the network. It was a known unknown.

Sometimes you can nudge people who drive in a Thaler-and-Sunstein way authors of the influential book on human behaviour. But sometimes you have to actually intervene. Among road chiefs in the US, meanwhile, sentiment towards the roundabout is doing a U-turn. Jeff Shaw, intersections programme manager at the Federal Highways Agency, explains that the better safety record of roundabouts in the US has meant that they are now the default option.