When Broward County bicycle coordinator Mark Horowitz suggested putting bike racks on buses more than a decade ago, people thought he was crazy. The bikes would fall off, they'd get stolen, no one would use the racks -- Horowitz heard all the complaints. Still he persevered. Two years ago Broward County transit officials finally agreed to try the racks; last summer Palm Beach County transit followed suit. Today officials in both counties declare their programs -- Broward's BYOB (Bring Your Own Bike) and Palm Beach County's BOB (Bikes On Board) -- unmitigated successes. An estimated 800 bicyclists are taking the bus daily in Broward, as are an estimated 500 people in Palm Beach. Pretty impressive numbers for transit systems that have struggled for years to increase ridership. In fact, officials say, they now face a different problem: More bicyclists want to use the buses than they can handle. Horowitz says that problem won't be solved easily or soon. Each rack can accommodate only two bikes; bigger racks would stick out too far, creating a safety hazard. But being too popular is a nice problem to have -- for a change.