Priority One Driving is when you drive fast with your lights and sirens going. It is used when the job you are attending is deemed urgent by the control room. They decided this based on the information they receive.
Unfortunately some people think this is a free license to drive wrecklessly and see what limits the vehicle can handle on the road. I have seen some absolutely shocking P1 driving, mainly from the Police. Once I was almost taken out by a Police car which came to a handbrake slide stop at an accident I was at. They literally stopped 1 ft away from me. If Joe public did this they would be arrested and charged with wreckless driving but because its the Police they seem to be immune.
Its a funny thing but there seems to be a direct link for some people between turning on the lights and siren and switching on a speed demon channel in that persons head. They become this completely different person who think they are totally invinsible and immune from danger. They transform to a racing car driver who's main aim is to drive as fast and wrecklessly as they can, wheelspins included. Its actually quite frightening sitting next to them.
Now I, along with most other people that drive emergency service vehicles, love driving prioity one, but I tend to do so with resepct for other road users and do it with the main aim of arriving at the job safely. Crashing an emergency vehicle on the way to a call is definately not a cool thing to do and although it happens a lot less than it used to, it does still happen.
The vehicles are so much safer to drive these days with ABS brakes, air bags, power steering, uprated suspension and even stability control and I suspect this has had a lot to do with the crash rate being lower than before rather than less people driving wrecklessly.
Below was a video I shot of some Police cars driving down Auckands Queen St. This is an example of some good, safe P1 driving. They read the road ahead (and avoid crashing into a bus that does not see them until he goes around the corner), do not drive excessively fast for the conditions and even stop at the red traffic light to make sure everyone has seen them before proceeding! Most importantly, they arrived safely at their destination!