As in being stopped twice on the same offense?
How the **** do they expect you to do anything productive in society if you don't have a vehicle to do just that?
Explain it as nicely as you can. Tell them you were doing something to help solve the gas price crunch, reduce emissions. (even though the pollutants are probably 25 times that of a car, but the judge doesn't know that), and be a productive, working member of society. Nothing will change the fact that it is against the law though.
Just put on the biggest masquerade you can.