Last week, I attended a driving event at the GM Proving Ground in Milford MI. Driving through the campus, there were several places where roads converged at roundabouts (sometimes also known as rotaries) rather than intersections with stop signs. (I’ll have more to say about the content of that event later.) But even before I arrived, I had gone through a couple more roundabouts on the roads in Milford, MI, where GM’s Proving Ground is located. That started me thinking about roundabouts, and how they are greener than standard intersections.
A modern roundabout … is a circle “designed for very low traffic speeds, about 15 mph.” Entrances and exits are curved so that motorists must travel slowly — far different from the rotaries of decades ago, which typically allowed drivers to enter at 35 mph or faster. The Institute says a modern roundabout typically needs to be about 100 feet across so that it can be properly designed to slow the entering traffic. (New Urban News)
Because the traffic only needs to slow down rather than stopping, all the cars traveling through a roundabout avoid the stop-and-go of a stop sign or a red light. Collectively, this adds up to thousands of gallons of fuel saved for each intersection. Avoiding a full stop also allows each driver to get through the intersection faster, which helps make overall travel times shorter.