A State Police trooper suffered a concussion on Thursday night as he was responding to a car crash on Route 2 in Lexington.
The trooper, identified as Daniel Hanafin, was injured when a tree branch fell on his head as he was trying to help the driver of a crashed car, according to State Police.
Police said the car crashed into a barrier and then another barrier on the off-ramp of Route 2. The car then flipped over the barrier and into the Cambridge Reservoir.
Police say the driver, who was trapped upside down inside the car, called 911.
Lincoln Fire Chief Steve Carter said the driver, a 50-year-old Bridgewater man, is lucky to be alive since the air pocket he was in would not have lasted long.
State Police said crews had to use special equipment to extricate the driver from the car.
The driver was taken to a hospital. The trooper was also taken to a hospital and later released.
Police are investigating the crash.
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