I spent 5 years in two different fire departments and by my time, even the ambulances had been upgraded to full Class B truck chassis so the steering wheel is horizontal to the body. And turning that wheel usually involved a whole body motion because it was so big and those things handle like a barge.

But, since the advent of airbags, it is now recommended that you keep your hands at the 7 o'clock & 4 o'clock positions instead of at 10 & 2. The reason? If you are in an accident with your hands at 10 & 2 and your airbag deploys it frequently breaks both of your forearms. Since airbags deploy up towards your face hands held at the lower position usually doesn't result in the same injury.

Yet, even knowing that I find that I usually wind up at the old familiar position.