I would argue that disabling screen functions while the car is moving is more of a safety hazard than not doing so. Unpredictable interfaces are distracting. Would you rather drive next to me while I reach over and adjust the bass on my car stereo or while I spend a few minutes screwing with my car stereo only to learn that I cannot adjust the bass while the car is moving? In many cars, I could simply ask my passenger to adjust the bass. But in my car I will need to pull over on the side of the freeway to adjust the bass and then merge back into traffic from a dead stop. It's a safety feature.