Urban Transformation

The US is saving lives - and energy costs - with this one radical change to its traffic system

Cars drive round a roundabout in New York August 24, 2011. New York will mark the 10th anniversary of the attacks on the World Trade Center with ceremonies on September 11. REUTERS/Lucas Jackson (UNITED STATES - Tags: CITYSCAPE)

Road safety ... how one US state is circling back on a good idea. Image: REUTERS/Lucas Jackson

Douglas Broom
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This article is part of: Urban Transformation Summit

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  • Traffic lights are often seen as the best solution to road safety at junctions.
  • But a growing number of US states are replacing them with roundabouts.
  • And they are saving lives as well as reducing air pollution.

Here’s a controversial idea that turns conventional thinking about road safety on its head: traffic lights cause accidents, increase pollution and we’d be better off without them.

Faced with a rising toll of deaths and injuries at traffic-light-controlled junctions, a growing number of states in the US are replacing them with roundabouts at road intersections. Those that have claim the improvements in road safety have been dramatic.

When it comes to the number of roundabouts already in place, the US is lagging behind other developed countries with just 73 per 1 million inhabitants. There are currently estimated to be around 7,900 in total across the US, according to data collected by a nationwide database.

The US has proportionately few roundabouts for the size of its population, but the appetite for them is growing.
The US has proportionately few roundabouts for the size of its population, but the appetite for them is growing.

But the benefits of expanding this figure are clear. The state of Indiana, for example, has installed 256 roundabouts (also known as traffic circles) to replace traffic lights since 2016. This has reduced accidents, delays, fuel consumption, air pollution and construction costs, it says.

Overall, it has seen a 90% reduction in fatalities, 76% fewer injuries and a 30%-40% fall in the number of accidents involving pedestrians, the state says, adding that roundabouts also increase road capacity by up to 50%.


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Deadly junctions

Across the US, two people are killed every day by drivers running red lights, according to the American Automobile Association, which says most of the victims are passengers in other vehicles or pedestrians.

The Federal Highway Administration (FHWA) says a third of all road-junction deaths occur at those with traffic lights. And according to the US National Coalition for Safer Roads, close to 850 people are killed every year by drivers ignoring red lights, while 143,000 are injured.

Road safety has been one of the issues under discussion at the World Economic Forum’s Urban Transformation Summit in Detroit, Michigan, from 6 to 8 December 2021. The state is one of many across the US adopting roundabouts to improve road safety.

Across the US, two people are killed every day by drivers running red lights.
Across the US, two people are killed every day by drivers running red lights.

Solutions across states

Neighbouring Wisconsin, which with 500 “traffic circles” has the most roundabouts of any US state, credits them with a “significant” reduction in road fatalities. Each roundabout is also reported to save around $5,000 a year on the State’s electricity bills.

“Overall, we see fatalities and serious injuries almost go down to nothing in roundabouts,” Andrea Bill of the Traffic Operations and Safety Laboratory at the University of Wisconsin-Madison told the Milwaukee Journal Sentinel.

The average roundabout has only eight points of potential collision compared with 32 at a normal four-way intersection, the US Department of Transportation points out in its report Roundabouts: An Informational Guide. It also says they are safer for pedestrians because drivers have to slow down to use them.

But it's not just red lights that cause deaths and injuries. Two-fifths of all San Francisco’s traffic fatalities are caused by cars turning left, whose drivers fail to spot pedestrians on crosswalks (pedestrian crossings), according to the city’s Municipal Transportation Agency.

The agency’s solution is to install vertical posts, rubber speed bumps and painted areas on the road to encourage drivers to slow down and look out for people crossing the road. It’s part of the city’s Vision Zero programme to eliminate road deaths altogether.

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