I've been tested only twice in my life (I'm nearly 60), once while in college for an engineering internship at IBM and once five years ago when I started driving a school bus. I actually failed the IBM drug test (for marijuana) but they just told me to "clean up my act" and gave me the intership anyway. I'm kind of OK with drug testing school bus drivers only because there's not really any way of testing whether or not a driver is currently high. On the other hand, they don't regularly test drivers for alcohol and it's more common than most parents would want to know for drivers to be drunk.