Ohio.gov State Agencies  |  Online Services
Skip Ribbon Commands
Skip to main content
Navigate Up
Sign In


Roundabouts At A Glance...

Roundabouts are circular intersections that require all entering traffic to yield at entry. Geometric features of a roundabout include channelized approaches, geometric curvature that ensures travel speeds within the roundabout are around 30 mph or less, and diameters usually between 80 to 200 feet. They are designed to be safer and more efficient than a traditional intersection. The geometry creates a low speed (20-30 mph) environment inside the circulatory roadway, as well as at the entry and exit locations. The geometry also prevents high angle crashes such as “T-bone” and left turn angle crashes. Lower angle, low speed crashes tend to be less severe than higher angle, high speed crashes. 



 Understanding Roundabouts

Roundabout Safety
Roundabouts are one of the most effective intersection control treatments available with the added benefit of calming traffic. They limit vehicle speeds to approximately 20 mph and can control vehicle speeds on four roads simultaneously. Roundabouts typically reduce crashes by 40 to 60 percent, reduce injury by 35 to 80 percent and almost completely eliminate incapacitating injury and fatal crashes. Community gateways and main roadways are effective locations for roundabouts as they slow traffic and provide space for an aesthetically pleasing entrance treatment.
Roundabouts vs. Traffic Signals
Roundabouts have proven to be much safer than traffic signals. The projected injury crash rate for roundabouts is half that of traditional signals.
Roundabout Crash Reduction
There are two basic premises in which roundabouts achieve crash reductions and greatly reduce severity on those few crashes that do occur. One is the simple decision making and the second is the low level of conflicts. At a four-way intersection, there are 32 possible conflict points between vehicles, whereas there are only eight at roundabouts.
Modern Roundabouts vs. Traffic Circles
There are many differences between roundabouts and traffic circles. Unlike traffic circles, roundabouts are used on higher volume streets to allocate right of way between competing intersection movements. Traffic circles have a large diameter, which contributes to high circulating speeds; roundabouts have a smaller diameter, promoting low circulating speeds. Roundabouts have lower entry speeds compared to traffic circles and feature a yield at every entry point, promoting low speed and no weaving.
Driving Modern Roundabouts
Research shows that drivers quickly adapt to the roundabout traffic flow. For instance, Vail and Avon, Colorado, both feature many high capacity roundabouts and are major tourist destinations with thousands of first-time roundabout drivers using the roundabout intersections each year. Despite large numbers of drivers who have not driven roundabouts previously, these intersections work well and do not confuse motorists. Proper use of signing and road striping at roundabouts assists motorists and minimizes the potential for confusion.

 Roundabout Driving Tips


 Roundabout FAQs

Get Microsoft Silverlight
Get Microsoft Silverlight

 Lawrence County: Solida Road

Under the direction of the Lawrence County Engineer's Office, this project included the construction of a roundabout on C.R. 18 (Solida Road) at the U.S. 52 East off-ramp and the intersection of Collins Avenue/Commerce Drive.
Contractors: Allard Excavation
Cost: $1.8 million
Schedule: Summer 2018 - Winter 2019

 Highland County: Hobart Road

The project was the construction of a 1.2-mile road to extend Hobart Drive from its terminus near U.S. Route 62 at the northern corporation limit of Hillsboro to S.R. 73 at the city’s west side. Construction also included improving Hobart Drive’s intersection with U.S. 62 by installing turn lanes; installing a traffic signal at the intersection with U.S. 62; and improving Careytown Road with the construction of a roundabout.
Contractors: John R. Jurgensen Company
Cost: $6.9 million
Schedule: Spring 2015 - Summer 2016

 Ross County: S.R. 207 & S.R. 159


The Ross-207 Extension project calls for the extension of S.R. 207 from U.S. 23 to S.R. 159. In addition to addressing other improvements, roundabouts will be constructed at the new route's  junction with S.R. 159 and at the junction of S.R. 180 and S.R. 159.

Contractors: Shelly & Sands, Inc.
$6.67 million
Schedule: Fall 2019 - Fall 2020


 Jackson County: McCarty Lane

​Project included the construction of an overpass over U.S. Route 35 at Jackson to relocate the at-grade intersection of McCarty Lane and Keystone Furnace Road with U.S. 35. Construction also included relocating Industry Drive, McCarty Lane and Acey Avenue and constructing a roundabout at the McCarty Lane and Acey Avenue intersection.
Contractors: Beaver Excavating
$4.86 million
Schedule: Spring 2014 - Fall 2015