[jackowayed]

That's another advantage of Bus Rapid Transit over trains. It's much cheaper to run one bus than one train, and the vehicles are generally smaller, so they run more of them for the same usage, meaning you generally aren't scheduled to wait as long. Of course, things can still go wrong.

VTA's rapid bus (the 522) runs every 15 minutes at rush hour, and the non-rapid one runs every 11. Off-hours is every 20-30 for each, but that's still 2-3x as often as Caltrain.