They may look similar, but as far as professional engineers are concerned, there is a difference between a traffic circle and a roundabout.
Upper Arlington already has a traffic circle in front of the Upper Arlington Library's Miller Park branch, where Tremont Road and Arlington Avenue intersect. The city is preparing to build a roundabout on Waltham Road that city officials say will be more specialized for traffic-calming and pedestrian safety than the circle.
UA officials call it the city's first modern roundabout.
"The Waltham roundabout has been designed to control entrance, exit and circulation speeds," said Emma Speight, Upper Arlington community affairs director. "This is done by the angles into and out of the roundabout and the diameter of the center island.
"It also provides a refuge (island) for pedestrians at all four legs -- you only have to cross one lane direction of traffic at a time," she explained. "The feature at Miller Park entailed working with existing right of way. Therefore, some of the travel lanes coming into it are not curved to slow traffic and (that) will be the case with the Waltham roundabout."
The Waltham Road roundabout will be constructed at the roadway's intersection with North Star Road, where Waltham connects to Kinnear Road in Columbus.
According to city officials, the road reconstruction is needed to address general deterioration and the roundabout is the best option available to reduce vehicle stacking and to calm traffic, which is expected to increase as Ohio State University begins to develop land along Kinnear Road.
"OSU has a master plan for its western lands," Upper Arlington City Engineer Dave Parkinson said June 24. "When that (area) grows, the traffic counts in that section of town will grow with it.
"The roundabout is the cheapest, most efficient and most effective option. It also provides the least amount of impact to residents on the west side of North Star."
The roundabout project is the second phase of Waltham Road's reconstruction.
In 2010, the city installed a new water line on Waltham from Andover to North Star and that section of the road also was rebuilt.
The project included the installation of a six-foot wide sidewalk on the south side of Waltham, street lights and the construction of a new parking lane on Waltham's south side, at a cost of $942,000.
Upper Arlington has secured an $824,000 grant and $276,000 loan for the roundabout through the Ohio Public Works Commission.
With the OPWC funding and loan, the city's initial costs for the project will be $1.262 million. It will have 24 years to repay the loan.
Speight said the benefits of modern roundabouts include encouraging a more continuous flow of cars through an intersection, with fewer stops and starts. She also said engineering studies suggest motorists pay more attention as they come to a roundabout because they know cars may already be on it and therefore have the right of way.
"With traffic signals, motorists have a tendency to trust that all other motorists are watching and obeying the signals -- forgetting to check both ways to be sure cars are not still traveling toward them," she said. "With the roundabout design for Waltham, there will be islands between lanes, providing pedestrians safer passage across the street."
According to Speight, the Miller Park traffic circle was first installed on a trial basis in 2004. It was permanently installed in 2010 as part of an Arlington Avenue water line replacement and reconstruction project.