A 22-year-old Carver man was seriously injured in a single-car accident last week at the intersection of High and Gate streets. Police responded to reports of a crash early Monday morning in which a 1997 Toyota Camry crashed into a tree. The driver, Brandon Kingston, was unconscious and had to be extricated from the car by the Fire Department. He was taken to Jordan Hospital in Plymouth with severe head trauma, then transported to Boston Medical Center by MedFlight ambulance. Police Chief Michael Miksch said speed appeared to be a factor in the accident. The crash remains under investigation.