kaled - 11:27 pm on Oct 20, 2010 (gmt 0)
That kind of driving can be indicative of drugs so you certainly did the right thing by reporting it. So that leaves the question of who do you report it to...
I live in the UK and things are somewhat different here (no dedicated school buses for starters) but I'd probably have opted for reporting the incident to the police. They have so many forms to fill in and boxes to tick that they would have no alternative but to investigate thoroughly - probably too thoroughly.
After reporting something like this, the likelihood is that no action will ultimately be taken, but you'd feel pretty bad if there was a serious accident some time later - you'd be left wondering if you could have prevented it.