I have a 24 mile each way commute. Always on a road bike. Some days, work and family commitments don't allow cycling both ways. I leave the car in our garage at work. Cycle home and back to work in the morning. Works if you have a secure place to leave the car. It's also a way to restock clean clothes. I tried the seat post rack thing. It rubbed through my expensive cycling shorts due to my large legs or my 34.9 seat post or both. I've done it with a backpack but it's a pain.

Work is always better when I bike rather than drive to work.