You may not have noticed it, but work on the proposed expansion of the Riverside traffic circle has already begun, according to Bill Hillman, the chief engineer for the Suffolk County Department of Public Works.
The initiation work involves moving some utilities, such as water and gas mains, in anticipation of the overall job next spring, which officials say could take as long as two years to complete.
“Come April, you should really start to see some substantial work,” Mr. Hillman told members of Southampton Town’s Riverside Economic Development Task Force Monday. The job will be done primarily at night, between 10 p.m. and 6 a.m.
“Looking at the plans, it looks great,” said Southampton Town Supervisor Jay Schneiderman, who voted for much of the funding for the project when he was a county legislator.
“It’s an incredible project for this area” he said. “Finally, the day has come.”
Design work on the project began in early 2011. The county awarded the contract for the job to Pioneer Landscaping and Asphalt Paving of Kings Park late last year.
The work is expected to take at least 18 months.
“We’ll be lucky if it’s done in 18 months,” Mr. Hillman said. “We were considering giving them 24 months.”
There is no penalty built into the contract if the contractor fails to meet that completion date, he said. Usually, if there’s a penalty involved, there also has to be incentives to meet certain goals, and the county didn’t have enough money to include that in the contract.
The project’s cost went from $4 million in early 2016 to $5.2 million, as additional money was included for drainage and other items.
At different times, different roadways will be closed overnight, Mr. Hillman said.
“When you close a substantial section of road, they can really get a lot of work done,” he said. The contract can work during the day, but cannot close down any roads after 6 a.m. and before 10 p.m.
The night work requirement drove up the price of the job, but “it was really needed,” Mr. Hillman said.
Between Memorial Day and Labor Day, the work will be done from Monday to Thursday, and in the months after that, it will be done on Sunday through Thursday, Mr. Hillman said.
The plan is to convert the one-lane traffic circle into a two-lane roundabout.
A roundabout has different approach angles than a traffic circle to slow cars down as they enter, according to the state Department of Transportation.
The Riverside traffic circle is unique because it has five “legs” — Peconic Avenue, Lake Avenue, Nugent Drive, Flanders Road, and Riverleigh Avenue — that enter and exit the circle, Mr. Hillman said. Traffic also enters from Woodhull Avenue and from the parking lot to the adjacent Shell Station.
Initially, the DPW wanted to eliminate one of the five legs to make it a four-leg roundabout, which it felt would run smoother. But that ran into opposition when the county proposed eliminating Riverleigh Avenue, which is used by many emergency service vehicles as well as by the more than 500 residents of the Riverwoods mobile home park.
“This is not a normal project; this is really complex,” Mr. Hillman said.
The county will notify emergency services when it closes a road, and “variable message signs” will be in the vicinity to warn people when work is scheduled.
Still, County Legislator Bridget Fleming (D-Sag Harbor) suggested possibly using the communications network set up by the Riverside Rediscovered project to warn as many people as possible when road closures are occurring.
Town officials also suggesting having groundbreaking ceremony to alert people as to when the project begins.