Five people were treated at Calvert Memorial Hospital for minor injuries yesterday after a 10-car collision on Route 4 and Talbott Road in Lothian, county police said.
There were no serious injuries in the 7 a.m. accident.
Police did not release the names of anyone involved in the accident, which began when a motorist northbound on Route 4 was hit from behind when she stopped for traffic ahead of her.
That collision caused a chain reaction, as nine other vehicles rear-ended the vehicles in front of them.
A school bus that had stopped at the Route 4 crossroads may have led to the accident, traffic investigators said.
The bus was at the bottom of a hill, and vehicles coming over the hill in the 55-mph zone may have been driving too fast to stop, police said.