I'm a car/bike commuter. The route from home to work is 26 miles each way with lots of hills and narrow, busy, winding roads at the beginning/end. As it is, I can easily manage 12-15 miles each way on a daily basis. Not sure how far you are riding, but you may want to consider riding the entire route. You could also try driving to work with your bike, leaving car at work overnight, riding home, riding in, driving home with bike. Works for some.