Most states have some sort of "Move Over" law requiring drivers to change lanes or slow down when passing emergency vehicles that are stopped on the side of the road, and the reason for these laws is to prevent what happened to Maryland state trooper David Avila. He had just pulled over a Hyundai Santa Fe when a semi truck veered onto the shoulder, hit the parked police car and clipped Avila, who was standing next to the pulled-over vehicle.
The incident happened on June 14, and it was all captured on the cruiser's dash camera. After being hit by the truck, Avila staggered over to the guard rail before collapsing. There is no audio in the YouTube video, but you can hear what happened in the video on the Today Show by scrolling down. Just seconds before he was hit, you can hear the truck running over the rumble strips, and even after he was injured, Avila remained aware of the situation by telling the motorist to remain in his vehicle. He had injuries to his shoulder, back and leg, and the patrolman remains in physical therapy.
On top of the failure of the semi truck to move over, the motorist in the Hyundai also stopped on a part of the shoulder that was very narrow, making the situation even more dangerous for Avila. As for the truck driver, he has been identified as William Riegel, Jr. of Pennsylvania. Riegel was subsequently fined $100 for negligent driving and failing to obey the move over law.
Scroll down to watch the video and the news report of the incident. Warning: the video is a bit graphic, as it shows the trooper being clipped by the truck.