Dublin Embraces Safety Of Roundabouts
In Columbus, red light cameras are being touted as a way to make intersections safer. In nearby Dublin, engineers believe that in some cases getting rid of traffic lights altogether is the key to protecting motorists. That's why the Columbus suburb has converted a handful of intersections to roundabouts.
Traffic is moving briskly through this intersection on Cemetery Road in Hilliard. There are no traffic lights or stop signs here; only yield signs. This intersection is a roundabout. Engineers say roundabouts are superior to other types of intersections. But not everyone agrees. Hilliard resident Pete Corna says he thinks this intersection should not have been converted to a roundabout.
"I think there's just too much traffic at that intersection for a roundabout," Corna says. "There's a school across the street, lots of crosswalks. And seems like there's going to be an accident waiting to happen."
But experts say roundabouts are extremely safe. Gene Russell is a professor emeritus at Kansas State University and Chair of the Transportation Research Board's task force on roundabouts.
"I think they're the safest, most efficient form of intersection traffic control that we have today," Russell says.
Russell says nationwide studies prove that roundabouts greatly reduce injuries and deaths.
"Roundabouts reduce all crashes 40 percent; injury crashes 80 percent and I think that's the most significant number. And it's predicted that they will reduce fatalities 90 percent. Now this is based on studies where traffic signals and stop signs have been converted to roundabouts." Russell says.
Here in Central Ohio, the City of Dublin's Engineering Director Paul Hammersmith is familiar with the studies and he's a big advocate of roundabouts. He says the city's first priority for its intersections is safety and installing a roundabout is always the city's first consideration.
"When we look at an intersection improvement we really look at the roundabout first, and if for some reason we can't construct a roundabout there, then we fall back to a signal improvement," Hammersmith says.
Dublin has more roundabouts than any other community in Central Ohio. The first was built six years ago; now 13 are in operation with 6 more being designed or planned.
Ken Richardson, Engineering Manager for the City of Dublin is eager to show interested people the fundamentals of roundabouts
"We're coming into a roundabout now," Richardson says. "You see the signing. And then there's a bit of a forced deflection. When you come up to a roundabout, yield to traffic in the roundabout. There's no one here so I can just proceed right into the roundabout. As I come around these cars should yield to me and they did "
When a vehicle enters the roundabout it's deflected to the right forcing it to slow down. That's one reason that roundabouts are much safer than intersections with traffic lights. All traffic moves in the same direction, counterclockwise, making it almost impossible for deadly t-bone collisions to occur. Dublin's director of engineering Paul Hammersmith:
"When we're coming to a major intersection we're slowing vehicles down, we have good visibility with other approaching vehicles, and then if somebody does make a mistake and we do have an accident, it's a sideswipe type collision, property damage only; very, very, very rarely have an injury accident in a roundabout or significant property damage. And that's really where the safety benefit comes," Hammersmith says.
"Most of the speeds in the roundabout are about 23, 25 miles an hour," says Ken Richardson. "And that slower speed, if there is a potential collision with another vehicle, at that speed you usually can correct and avoid a collision."
And there are more benefits according to Richardson:
"This is a 35 miles per hour road we're coming up. Again we have to decrease speed. And then we're deflecting to the right and there's no cars so we just go around the roundabout and continue north. And we're through the intersection.
"And that took how long?"
"Oh that was probably, two three seconds," Richardson says.
"Whereas you could have sat at the light "
"You could have sat at the light and just waited and waited and waited," says Richardson.
That means that emissions are lower and that less gasoline or diesel is being burned. They provide for safe U-Turns, Richardson says, and he says roundabouts are quieter because cars aren't screeching tires when a light turns green.
Dublin engineering director Paul Hammersmith says the cost of building a roundabout is about the same as building an intersection with traffic lights. But he says there are circumstances when roundabouts won't fit the intersection.