Ours is a different system again. Because each station must be manned we have to have a pre-arranged cover person for days, and same for nights. Usually rotate two of one, then a few weeks later, two of the other, 8 to 10 person team. We get an hours "phone time" paid per standby, and travel each way plus the 12hrs that you're at work should the phone ring, all at overtime rate. It complicates your time off waiting for the call, but once the relevant 730 has passed you at least know you're free for that 12 hr period, or working it.
No Chebby or other company wagon tho. There is a mileage rate for travel on company time, but its not keeping up with real costs at the moment.