Crews were operating at the scene of a Personal Injury Crash with Ejection and Entrapment on Alleghney River Blvd. 221 Service w/ a crew of 2 was instructed to shut down the roadway at Allegheny River Blvd and Nadine Rd. while other units worked the crash. Approx 30 to 45 min into the operations the Service unit called Command reporting a car had run there road block and was requesting police. The 2 quick thinking FFon the truck were able to get out of the way and no injuries were reported. Both inidicated they heard the vehicle approaching with what sounded like a falt tire and moving at a slow rate of speed. as it got closer thry could see the driver was going to attempt to get between the Service Truck and a guard rail. The driver did get between the service and the gaurdrail but the FF were able to get the driver to stop and then removed the keys from the vehicle by telling the what appeared to be very intoxicated female driver they would change the change the tire for her. Police arrived and handle the situation from there. On a side note the Roadblock on the other end of the accident was provided by and Engine there were 3 cars that broke that roadblock during the course of the accident but fortunatley they did make it far due to the quick thinking of the FF that were there as well. What are people thinking when they see Fire and Police vehicles blocking roadway.