An Innovative Type of Traffic Control

For the first time in its history, MTO has assembled a Roundabout Implementation Team (RIT) to research and promote the use of roundabouts as an alternative form of traffic control at intersections on provincial highways. The team is comprised of members from Traffic Office, Design & Contract Standards Office, Central, Eastern, Northeastern and Southwestern regions. Its mandate is to look at roundabouts as an opportunity to reduce collisions, delays and fuel usage, while improving air quality through reduced vehicle emissions.

The construction of roundabouts is expanding throughout North America. The ministry's first roundabout at Highway 33 and County Road 1 in Picton, Prince Edward County is scheduled for construction in 2008. The proposal is for a one-lane roundabout with posted speeds of 80 km/h on the north and west approaches, and 60 km/h on the east and south approaches. A number of local road authorities, such as the Region of Waterloo and the City of Hamilton, have constructed roundabouts on municipal roads with a great deal of success.

From a traffic standpoint, improved safety and reduction in delays for drivers are the major benefits of roundabouts. A 2001 study of 23 intersections in the United States reported that converting intersections from traffic signals or stop signs to roundabouts reduced injury-related crashes by 80 percent and all crashes by 40%

Reductions in vehicle emissions resulting from the use of roundabouts are certainly an added bonus in today's environment, where increases in traffic volumes put an added strain on air quality.

Vehicle emissions caused by excessive idling time at signalized intersections can be significant, especially at complex intersections with protected turns and long cycle lengths. In contrast, the yield-at-entry feature of the modern roundabout allows traffic to proceed with minimal delay, stopping at the yield sign only when necessary.

Even in moderate traffic conditions, drivers are able to accept gaps for entry rather than wait through the equivalent of an entire signal cycle. Roundabouts keep traffic moving since fewer vehicles make a complete stop. These savings in time, energy and the environment can be considerable in urban areas.

In one study, replacing a signalized intersection with a roundabout reduced carbon monoxide emissions by 29 percent and nitrous oxide emissions by 21 percent2. In an additional study, replacing traffic signals and stop signs with roundabouts reduced carbon monoxide emissions by 32 percent, nitrous oxide emissions by 34 percent, carbon dioxide emissions by 37 percent, and hydrocarbon emissions by 42 percent3. Likewise, constructing roundabouts in place of traffic signals can reduce fuel consumption by about 30 percent2, 4. At 10 intersections studied in Virginia, this amounted to more than 200,000 gallons of fuel per year5.

Education will be a key component in helping Ontario drivers feels comfortable when driving a roundabout. Many motorists are not familiar with the rules of the road as they apply to roundabouts, and are therefore opposed to their installation. However, this opposition often turns to support and preference once a roundabout is installed and people become comfortable using it. As part of the education process, MTO has included instructions on how to drive a roundabout in the newly released version of the Official Driver's Handbook.

The use of the modern roundabout with its unique operating characteristics provides an innovative traffic control alternative for the ministry. "Consistent with our goal to improve driver safety and given research has shown the multiple benefits associated with roundabouts, it makes sense that we advance their implementation," states Gerry Chaput, Chief Engineer/Director, Highway Standards Branch. The appropriate use of roundabouts will help improve safety while reducing congestion and vehicle emissions.