An in-car video system has helped a Texas law enforcement agency piece together the details of the harrowing encounter of one of its sergeants, who parked his patrol car on a bridge to help a stranded motorist change a tire.
Sgt. Matthew Davidson was grazed by a 200-pound wheel that broke free from an 18-wheel big rig, as he watched a motorist change the tire of his pickup truck alongside the Fred Hartman Bridge east of Houston. The bridge carries travelers between La Porte and Baytown.











