Town: Consultant Finds that Gerdes-South Avenue Intersection Functions at Lowest Possible Level of Service

A New Haven-based consulting firm has found that the intersection of Gerdes Road and South Avenue—long backed-up with Merritt Parkway-skirting motorists using navigation apps at rush hour, causing safety and other concerns for residents—functions at the lowest possible level of service, officials say.

Traffic engineers at the firm of Hardesty & Hanover have assigned a grade of F to the intersection on a scale of A to F with “F being the worst,” for westbound traffic in the morning, according to Public Works Director Tiger Mann. 

The same intersection functions at a level D in the afternoon, Mann told members of the Police Commission at their Feb. 21 meeting, held at Town Hall and via videoconference.

Yet in looking at how the intersection will perform over a five-year period, the consultants “came up with the fact that if they took nine seconds off of one of the legs, basically the northbound leg on South Avenue, and gave it to Gerdes, it would raise Gerdes from an F to a D,” Mann said, with C and D being acceptable and common service levels for such intersections.

By transferring nine seconds of green light from South Avenue to the commuter traffic, “the queuing lengths on Gerdes would reduce from 700 feet to somewhere on the order of below 500 feet, which I think would almost put us before the intersection of Conrad Road ,and then prevent some people from shooting up Conrad Road,” Mann said.

He continued, “And then overall, there would be a savings of somewhere on the order of 60 seconds per person traveling through that intersection. So the overall travel delay would be reduced.”

The next step is for the town to request the change from the state Department of Transportation (South Avenue doubles there as state Route 124), Mann said.

The comments came during an update to the Commission regarding the town’s work to improve traffic flow on Gerdes Road as well as to figure out how to reduce speeding vehicles using an offshoot street, Conrad Road, to get around the problematic intersection a different way.

Town officials have been working on a solution to the area since residents raised concerns last summer. Plans call for creation of a “mini-roundabout” in the area. A traffic diversion experiment last fall to close off Conrad Road to motorists was quickly abandoned.

Once the state considers the change at the light signal, the Commission as New Canaan’s designated “local traffic authority” may need to vote on it, Mann said.

Regarding the intersection of Conrad and Wiffle Tree, Hardesty & Hanover currently is reviewing newly issued federal guidelines regarding roundabouts, Mann said.

“They’re looking at their design and analyzing that to see if it fits with both of the new regulations,” he said. “We believe it will. And then they’re going to come forward with a couple of different options and then some renderings and then we’ll be able to present to you, hopefully next month, with those ideas and then show you exactly where it is and then how the intersection itself would function.”

Mann noted that changing the timing of the light would affect the grade of other approaches to the intersection, so the firm is “trying to give us something that would work for us bring us up to what would the DOT would be considered an acceptable level and then not drop their legs out of what they would consider an acceptable level trying this and trying to make sure that we balance it between the two,” Mann said.

“I think it’s something that we should pursue and it can be handled strictly by timing of the cabinet,” he said. “Nothing else has to happen in the intersection for it to happen. Someone just has to go in and reprogram the cabinet itself. Very minimal amount of work, very minimal cost. We just need their [state DOT] approval.”