A popular way to get in shape, save money and help reduce traffic gridlock is to commute to work by bicycle. It can be more fun than going alone and will help you stick with your program until it becomes a routine. If you have a long commute, you can build up to it by driving part way and riding the rest.
Many commuters also ride to a place where they can use mass transportation for the rest of the trip.
Join a bike commuting program or start one where you work. Some companies offer cash incentives or bike gear to employees who commute by bike because it helps reduce congestion in the company parking lot. Purchase a cycling garment bag or panniers to carry your clothes to work. Some commuters drive to work with a week's worth of clothes on a Monday or Friday to avoid having to carry clothes on their bike every day. Wear highly visible, reflective bike clothing and attach lights, reflectors and a rearview mirror to your bike.