Lots of ways to spot company car drivers (I was one for a while, biggest tax liability going - take the cash option) Anway, and this applies to rental fleets as well;-
1. Company cars have much higher in gears speeds that normal cars, especially in reverse.
2. Accelerator and brake pedals replaced by foot operated on/off switches
3. Special tyres that allow you to stop in 3 feet at 80 mph
4. Front bumpers treated to resist exhaust stains from the vehicle in front
5. Cruise control calibrated not in mph but instead adjustable in feet (0-10) from the car in front.
6. Floorpan is a surrogate dustin/ashtray
I'm sure I can come up with more
Rgds,
Paul.