As to taking a call leave it, if it's important they'll call back, failing that at the next safe opportunity, pull over,check the number & call em' back, if you've got someone in the car with you let them answer & take a message. Where is the difficulty in that ?
As to the Smoking in cars, I believe it's up to the individual & their conscience as to if they do or they don't in their "private Vehicle", as yet the traffic Taliban haven't breached this particular bastion, but they are trying (Gawd bless 'em). Works Vehicles though different ball game, officially it's a nono, but who can control it ?