NORFOLK, Neb. -- A Nebraska sheriff's deputy jumped into the cab of a runaway semitrailer after the driver apparently passed out at the wheel, keeping the vehicle from crashing off a busy viaduct bridge. Deputies responding to a 911 call about a reckless semi on U.S. 81 caught up with the truck, which slowed as it neared Norfolk, allowing deputy Todd Volk to jump from a cruiser onto the highway, then into the truck's cab, where he was able to stop the big rig on the bridge.