ACTON -- State police say they are investigating a serious single-vehicle crash on Route 2 on Thursday morning that resulted in the ejection of a driver.

The crash occurred on the eastbound side of the highway, just east of Exit 42, about 5:30 a.m. Trooper Dustin Fitch said the driver was ejected from the vehicle and the vehicle rolled over, which is registered to a Littleton resident. When officers arrived on scene, they reported the driver was conscious and responsive, though they were unable to confirm if that person was the owner of the vehicle. The driver was then taken to Emerson Hospital for treatment with serious injuries and was the lone occupant inside the vehicle, a Saturn Ion.

The driver was later transported by MedFlight helicopter to another hospital.

Fitch said the cause of the crash is unknown. He said several spinouts were reported earlier today due to icy conditions but could not say if that played a role.

Limited information was available on the driver and make of the vehicle Thursday morning, and the location of the second hospital was not known.

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