Cars with ears

Imagine you are driving down the road. You need to make a phone call. You pull over but you get a very weak signal. You are forced to drive around until the signal gets strong enough to make a call. Wouldn't it be nice to have a signal booster?

All cars should have built in signal boosters for cell phones. The booster would pick up any cell phone signals and amplify them. Making a cell phone call in the vicinity of a car would be much easier. If there were enough cars, they could bridge gaps in cell phone network coverage.