It's called a "cell phone". I'm begining to think it's impossible for a woman to drive a vehicle without one of those things held to her ear - though I see plenty of "girly-men" doing the same. It's particularly bad during the "soccer mom hour" on weekdays and occasionally results in SUVs attempting to mate.
If these folks didn't have to steer they'd be holding a Starbucks cup in the other hand. They have to alternate now, so they'd love to have a road that drives the car for them.