CT 66 Marlborough - Segment 3: CT 2 Interchange

Current Layout

Current Layout

To the east of Marlborough center, CT 66 intersects CT 2, a freeway that connects Hartford and Norwich. This is a key interchange on CT 2; a high amount of traffic to and from Hartford accesses CT 2 here. Traffic at this interchange is increasing as the residential population of Marlborough, East Hampton, and Hebron increases. The distance between the two ramp intersections is 0.16 miles.

The traffic problems at this interchange are caused by high amounts of left-turning traffic off of CT 2 and CT 66. Currently, the CT 2 offramps are controlled by stop signs. These ramps have turn channels; there are separate queues for left- and right-turning traffic. However, during rush hour, sometimes queues of up to 15 cars wait to turn left, interfering with right-turning traffic. On CT 66, there are no left turn lanes for traffic turning onto CT 2. There are not as many issues here, because there is a wide shoulder on CT 66 East to allow through traffic to skirt around the turning traffic. CT 66 West has two lanes through the interchange. CT 66 heads uphill from east to west, so the left lane westbound acts as a passing lane, unless there is a vehicle waiting to turn left onto CT 2.


Reconfigured Layout

To solve the issues with the high volume of turning traffic, roundabouts are a good solution. Roundabouts would help facilitate turning traffic easier than traffic signals. During rush hour, traffic turning off of CT 2 would not have to wait for both directions of CT 66 to clear; because of the design of the roundabouts, there only needs to be a gap in traffic from the left. Since off-peak traffic is significantly lower, traffic may not need to stop at all at these times.

Even though the amount of traffic is increasing, roundabouts would be able to handle existing traffic, plus some future growth. There is enough existing right-of-way to install roundabouts. The only hindrance is that this interchange is on a hill. The grade is not overly steep, so with proper engineering, roundabouts should still be feasible here. Another reason to use roundabouts is that a gateway to the town center can be formed. Traffic will be slowed, announcing the presence of the town center.

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