by: Erica Ricci, Michael Henrich Updated: Mar 11, 2016 - 9:37 AM

LEXINGTON, Mass. —

State Police rescued a driver Thursday after his car went off the highway and into Concord Reservoir.

Police say the 50-year-old driver hit a construction barrier before flipping into the water. As the car was in the water, the driver was able to free himself from the front seat and into the back seat where there was an air bubble.

From there, the driver was able to call 911 on his cell phone and wait for troopers to arrive.

“If he hadn’t called us nobody would have found him for at least a day because of the location. He’s 35 feet down below over the guardrail. Maybe tomorrow one of the construction workers would have found him, but other than that he wouldn’t have been found,” State Police Sgt. Jeffrey Joachim said.

The driver was hospitalized for minor injuries. One trooper was hit by a tree limb during the rescue. Officials told FOX25's Michael Henrich that the trooper sustained a concussion and would be placed on paid medical leave.

According to police, the driver said he lost control when he hit a puddle. So far he has not been charged, but the investigation is on-going.

Police closed the ramp from Route 2 eastbound to I-95 southbound during their investigation and while removing the car from the water. The ramp was reopened just after 10:30 p.m. Thursday