Authorities have stepped up freeway patrols in the wake of a spate of shootings that have claimed the lives of a pregnant woman and a man and left another motorist wounded over the past two weeks.

The latest report of a freeway shooting came Thursday from a driver of a cement truck who said his vehicle's rear window was shot out.On Tuesday, police said someone in a stolen red sports car shot and killed Jennifer Montgomery and her unborn child on a local freeway. The woman was riding with her husband, Ricky Montgomery, 22.

Michael T. Bingham, 28, was shot to death on another freeway Saturday, police said.

No one was arrested in either incident.