Siobhan and Bryan Anderson were making their way to North Shore University Hospital in Manhasset around 7 a.m. Saturday after Siobhan's water broke, Newsday, Melville, N.Y., reported.
Siobhan's contractions intensified on the road and she asked Bryan to pull over on the Southern State Parkway, the report said.
"I'm going to deliver," she told him.
Bryan called 911 and state trooper Ron Ferraro arrived along with Nassau County police and medical technicians.
As medical technicians put Siobhan on a stretcher and were wheeling her to the ambulance, she gave birth to Gavin John.
The mother "literally delivered the baby on the stretcher on the road, with cars going by," said Nassau Officer Ron Gerlin.
Siobhan was then moved into the ambulance which began making its way to the nearest hospital, which was about 10 miles away.
However, when Siobhan couldn't hold back the second twin, the ambulance pulled off the Wantagh State Parkway to deliver Declan Michael.
"I was crying because it was so painful and I had no painkillers," Siobhan said. "They really wanted to come out."
Minutes later, the ambulance arrived at the Nassau University Medical Center, where the babies were brought into the delivery unit by officers.
"They were moving around, looking at the world. I thought it was beautiful," said Leila Ayers, a nurse in the unit.