The 10 and 2 o'clock hand position on the steering wheel is no longer recommend because

To avoid the airbag from hurting your arms and hands.

Explanation:

Because of the changes that have ocurred in the airbags and steering wheels, the airbags have been put in the steering column so they will deploy to protect the head and chest of the person driving. This means, that if you have your hand in the 10 and 2 o'clock hand position, if there is an accident and the airbag opens, your hands will be directly over it which can cause serious injuries. Because of this, experts are advising to place your hand lower like using a 8 and 4 o'clock hand position.