ALTHOUGH often criticised, traffic circles, or roundabouts, are highly effective in reducing the risk of accidents at intersections. For proof of this, look no further than Carmel, Indiana, considered a leader in the field, with around 140 roundabouts in the city.


The city of Carmel is now world-famous for its roundabouts. Since 1998, the city has built over 138 of them, mostly replacing traditional traffic lights. No other US city can boast as many.


In addition to improving traffic flow, especially during rush hour, roundabouts can significantly reduce the number of fatalities and serious-injury accidents. In Carmel, injury accidents have been reduced by about 80% and the number of accidents overall has been reduced by about 40% over the last 20 years. Moreover, roundabouts can help make it easier and safer for cyclists and pedestrians to get around.


In Carmel, there are literally roundabouts everywhere. And this can help significantly reduce CO2 emissions because, without traffic lights, drivers don't have to stop, but simply idle, which means they use less gas. And that's far from negligible, considering the number of roundabouts and journeys involved.


In addition, since they have no electrical infrastructure, roundabouts are more resistant to the severe weather that the United States can sometimes experience (storms, tornados, etc.). In fact, for the city of Carmel, these modern roundabouts represent the most sustainable intersections out there.


To help residents better understand these roundabouts, the city of Carmel has published a detailed map of their locations on its website, along with various tips on how to use them.


With a total of more than 100,000 roundabouts, France is the world champion in the field. In comparison, there are just 8,000 roundabouts in the whole of the United States.