What's the option?
3 miles in a car isn't good for it - the engine will barely get warm and will cause wear and carbon deposit problems.
Walking? 45 minutes?
Running would be quicker than walking, but a shower would be essential.
Cycling? Save petrol money, get some low grade exercise on the way in, and give it full beans on the way home and you'll be fitter, stronger, and healthier.
Where's the choice?
This is so true. My 3 year old car failed its first MOT on emissions - most of my journeys were about 3 miles round trip, and this was what spurred me to do more utility cycling and less driving.