Bassplayinbiker,

You might want to ask your school's Phys Ed department if any of them are interested in supporting you on this issue. They are likely to encourage the administration to support your travel mode because of its health and fitness benefits for you, and they may view your cycling as a good example for others. If they don't know anything about cycling, tell them that cycling has a lower fatality risk (per hour of activity) than swimming and has injury rates lower than most school sports such as soccer and basketball. Lastly, point out that you are much less likely to hurt anyone by cycling than by arriving in an automobile.

Two more points of advice: (1) you may want to keep your tool kit as well as some spare tubes and old spare tires in your locker in case of vandalism, (2) you may want to keep some emergency cash for a taxi with you. Hide the money in an envelope or somewere that will discourage you from spending it, so you will always have it for a real emergency.

-Steve Goodridge
http://humantransport.org/bicycledriving/