Authorities say the truck was parked behind a work zone and displaying a flashing yellow arrow when it was hit around 1 p.m. Thursday in Willington.
Police say a car driven by 47-year-old Kiran Shah, of New Jersey, moved into the right lane before striking the truck. The reason for the lane change is unknown.
Shah was taken to a hospital for evaluation, along with DOT workers Eric Christopher Hall, 46, and Joseph Csiki, 24, who were inside the truck.
Connecticut State Police are investigating the crash.
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