Thirteen cars crashed on the Baltimore beltway ramp to Interstate 83 Monday night, shutting down all lanes of the outer loop and backing up traffic for miles, State Police said.
The highway was reopened early Tuesday, and the crash is under investigation.
Eleven people were taken to hospitals after the pileup, which started at 9 p.m. when a vehicle hit the jersey wall and became disabled in the roadway, police said. None of the injuries were serious, police said.
A tractor trailer jackknifed, exacerbating the situation, and a private ambulance was involved, though it was not in service at the time, police said. The agency earlier reported four people had been taken to hospitals and 15 cars had been involved.