I only have a 7.5 mile commute each way. Living in a small rural community, I can go pretty much in a straight line on the bike, instead of following the highway that curves and winds itself. about 9 miles by car. It takes only a couple minutes longer on the bike, not bad considering my 30-35mph top speed. Its alot funner going down a cotton field, or ditch bank road at 30 than 100 on the highway. And no tickets on the bicycle!
The best part is no parking issues. I just pull it right up to the bike rack, lock it up and walk the 10' into my office. or drive arround one of the parking lots looking for a free place then only to walk 1/4 mile to the office. When I go home I motor passed my office mates as they walk to there cars. I love it!