let's go back to the report and see if we can extrapolate some reasoning:
2 passengers in the front
3 passengers in rear
night time
so, full boat of dudes making a beer run after wrenching? or bombing around town to check the veracity of repair and slamming some wobbly pops at the local, gettin' a little loose and frisky?
somebody in the car is definitely an instigator... but then again it don't take much to get all nimbly-bimbly when you're piloting a 340 4spd car...