The New Haven County crash happened around 3:15 a.m. Tuesday, June 18, in Branford.
According to Connecticut State Police, the tractor-trailer was parked just past a rest area on the shoulder when Josiah Lawrence Steinman, of New Haven, driving a 2019 Nissan Sentra north in the right lane, veered onto the shoulder "for an unknown reason," slamming into the back of the truck.
He was transported to Yale New Haven Hospital, where he later died from his injuries, state police said.
The tractor-trailer driver was not injured.
State Police said the Collision Analysis and Reconstruction Squad responded to assist in the investigation, which remains ongoing.
Witnesses are asked to contact Troop G at 203-696-2500.
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