We had one a couple years ago. We had two cars from the junkyard towed in while the kids were in class, and placed them in an accident scene. Then the principal had a fire drill, and all the kids came out to find the accident scene.
We were paged, and arrived with lights and sirens. We had the local helo come in, we had four students involved, with two fatalities-one pinned requiring extrication, and another injury. We blanketed the fatalities, the whole nine yards. Simulated IV's, etc. The impaired "driver" was uninjured. The LEO detained him, field tested and cuffed him. FD came and cut the victims out. Highway Patrol gave a speech about a particularly tough call he'd worked.
We had several parents call and thank us for the demo, saying the kids came home and told them about it and it opened up some conversations. It went well, and made an impact. If it stops one kid from drinking and driving, it was worth it.
Good luck with your presentation.