DOT presents plan for Five Corners roundabout

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By Shirley Murtha

Principal engineer for the design unit of the state Department of Transportation, William Britnell, presented an informative view of the DOT’s plan for alleviating the accident situation at the intersection of Rtes. 10/202, East Street and Notch Road. A large turnout of interested residents packed the Senior Center on March 25 to learn about this project.
As with the previous DOT presentation on plans to re-design the center intersections, this meeting was held to inform and gauge the response to the proposed changes before more time and money is spent on the project. If it goes forward, there will be another opportunity for town input at the 30-percent-complete design phase.
In 1995, Granby requested a traffic signal or a four-way stop at the intersection in question, but the request was denied after a study by the Capitol Region Council of Governments showed that the traffic volume at the site did not meet the level required for a signal or four-way. In 2010, the town re-aligned Notch and Quarry Roads in the hopes that a signal was then possible, but the traffic volume remains considerably under the minimum standard; in fact it isn’t even up to 50 percent of what is required. Britnell noted that signals do not slow down traffic, in fact they have the reverse effect as drivers speed up to get through the yellow lights.
The unusual statistic, and the one that prompts remedial action, is that of the relatively few crashes that take place at the intersection (12 in three years), there is an unusually high number of injuries (13). This is primarily due to the type of crash that is most common there: the “T-bone,” in which cars coming out of East Street or Notch Road are hit by north- or south-bound cars traveling Rte. 10/202. The sightline to the south is limited by the crest on Rte. 10/202. The crest was lowered a few years ago but not enough to improve safe visibility. Surprisingly, 85 percent of the traffic is travelling at 50 mph or less in the area.


Concept Plan for Roundabout on Route 10 at East Street and Notch Road

The state began discussions with the town in 2013 regarding the installation of a roundabout at the intersection. A roundabout differs from a rotary in that a roundabout provides for only a single lane of traffic. Access and departures from the roundabout are right-hand and traffic is forced to slow to 15 – 20 mph due to the narrow lane. Incoming drivers have the right-of-way; those already in the circle yield to the incoming. Rotaries, on the other hand, are mult-ilaned, requiring weaving and lane changes when an incoming car needs to take the next exit.
Roundabouts have been popular in Europe for much longer than here in the United States, but their popularity is increasing, with over 3,000 of them having been installed. They use less pavement than a rotary; reduce delays as there is no stopping; and they have lower maintenance costs. Although it is not a factor in Granby’s situation, roundabouts also reduce congestion, as traffic keeps moving.
The Insurance Institute for Highway Safety’s report on roundabouts concluded that they reduce the number and severity of crashes. They provide a 39 percent reduction in total crashes, with crash injuries reduced by 76 percent and fatalities by 90 percent.
At each of the entrance points to the roundabout, “splitter islands” are installed. (see photo). These are curb-height structures that guide traffic to the entrances. Longer ones are placed on the higher speed roads (Rte. 10/202 north and south in Granby’s case) and shorter ones on access roads (East Street and Notch Road in Granby.) The splitter islands provide places where pedestrians can wait for opportunities to cross. In 40 years of record keeping, no pedestrian fatalities have been recorded at roundabouts.
Britnell noted that when proposed, roundabouts are almost always controversial. The public doesn’t understand them and confuses them with rotaries (think Cape Cod). Prior to installation, 68 percent of those questioned are opposed to installation; after installation, 73 percent are in favor.
Regarding the cost of the roundabout project, Britnell said “first guess” is between $3 and 4 million, 80 percent of which will come from the federal government and 20 percent from the state. There will be no cost to the town of Granby.
If the proposal is accepted, the next steps are surveying, finalizing the design, obtaining permits and the taking of rights of way. Actual construction would begin in 2019. It is expected to be a one-season job, April to November. No detours are expected during construction.
If you have any questions or comments, you may contact Britnell at
Caption: Concept Plan for Roundabout on Route 10 at East Street and Notch Road