The intersection of Routes 82 and 85 in Salem, sometimes called the Four Corners, used to have a lot of crashes, many of them serious.

Now it doesn’t.

The reason for the welcome decline is deceptively simple: the state changed the geometry of the crossroads. In 2012, the Connecticut Department of Transportation installed a modern roundabout in the center of the intersection.

The numbers make the point: From 2003 through 2008, the junction saw an average of 22 crashes, nine of them injury-related, each year. However, from 2018 to 2022, the average was down to 10 crashes, one injury-related, each year — a 55% decline in crashes and a 90% drop in injury-related crashes.

“I think it has saved lives,” said Salem First Selectman Ed Chmielewski.

A retired New London police sergeant, Chmielewski said that before the roundabout was built, the intersection was “deadly, with numerous accidents.” Now, he said, “we get some fender-benders, but we’re not seeing serious injures and fatalities. Life Star isn’t landing to take people away.”

The data from Salem is reflected around the state and the country. According to the Federal Highway Administration, roundabouts have 78% fewer injury and fatal crashes than signal-controlled intersections and 82% fewer than two-way stop (sign) controlled intersections.

The need for safer roads is clear; 2022 was the deadliest on record for fatal car crashes in Connecticut, taking an estimated 368 lives.

The message is not lost. The state Department of Transportation and a good number of towns are moving briskly to build more roundabouts, among other safety measures, so there could be one coming to an intersection near you.

Yield on entry

Though they may appear similar, modern roundabouts are decidedly not the same as traditional rotaries, or traffic circles. The latter have dotted the country’s roadscape since at least 1905, when Manhattan’s Columbus Circle opened. The older circles or rotaries are typically larger than modern roundabouts, so drivers don’t necessarily have to slow down to enter them, especially since cars in the circle were supposed to yield to cars entering the circle. Well, some do and some don’t, often causing delays, confusion and crashes.

Hartford’s Pulaski Circle is a prominent example. The circle is at the end of the Whitehead Highway connector to I-91 and brings cars from the interstate to the Capitol area. There is room for two lanes, but they aren’t marked, creating something of a free-for-all at busy times.

According to a traffic analysis conducted as a part of the Greater Hartford Mobility Study, there were 109 crashes at Pulaski Circle from 2018 to 2022.

CDOT has eliminated some older traffic circles and turned a couple into modern roundabouts. That could well happen to Pulaski Circle. The department is in the “early concept design phase” of a redo of the intersection, said a CTDOT spokesperson.

The modern roundabout, invented in Britain in the 1960s, is a radical rethinking of the traffic circle. In the old rotary model, cars already in the circle were supposed to yield to cars entering the circle. But Old Blighty flipped the switch and required cars entering the roundabout to yield to those already in the circle, a concept known as “yield on entry.”

Roundabouts have raised center islands and raised medians or “splitter islands” in each leg of the intersection, which channels incoming cars off to the right in a counterclockwise direction around the circle, from which they can exit with a right turn onto an outgoing split lane. So, all traffic is going in the same direction, virtually eliminating head-on or right-angle collisions. About a quarter of fatal crashes, and half of injury-related crashes, happen in or around traditional intersections, according to the Federal Highway Administration.

Vehicles approaching the roundabout have to slow down, to find an opening to merge into the circle and then to follow the tight turning radius. Slowing is good; speed is a factor in most crashes and in about a third of fatal crashes. “Drivers Can’t Run Roundabouts” read a bumper sticker created some years ago to support a roundabout in eastern Connecticut.

Roundabouts can be built with multiple lanes, but virtually all in Connecticut are single-lane, considered the safest model. There are also mini or compact roundabouts, sometimes used at tight urban intersections.

ctmirror.org