BOSTON >> Police say a mother and her 5-month-old daughter were critically injured when they were hit by a car in Boston.

It happened just before 9 p.m. Thursday in Roxbury. Police say the two were hit on Humboldt Avenue and taken to Boston Medical Center with severe head trauma. Authorities didn't immediately identify them.

Police say they're trying to determine if speed was a factor in the crash. The driver remained at the scene. Further information wasn't immediately available.