I've been in 2 similar situations to this (and I apologize for the long rant):
My FI and I were renters and one of us always had to park our car in front of the house. Usually up on the sidewalk a bit (you know the bit of grass between the road and the sidewalk) because our street was so narrrow.
So we're behind the house bbq'ing and we hear this loud crunch and glass shattering. We go around to the front of the house to see some old guy in his pickup truck with a trailer behind it who had just taken out the side of FI's SUV! We called the cops and they said they'd look into it, but we had to pay our full deductible for the repairs as they never did find the guy!
A few days after the accident, before FI had the repairs done, FI was coming out of the video store and saw some old guy in a truck matching our description looking up close at his vehicle! FI got a full plate and reported it to the cops, still didn't get any results from the police around here. We were really pissed off that this guy was still driving around town when he really wasn't fit to do so, and that the cops weren't going to do anything about it.
I was driving down the road, I really hate driving on the highway in the winter, ESPECIALLY at night, so I was almost home after my 45 min commute. I was almost at the lights to turn up the hill to my neighbourhood when I get hit on my passenger side by a pickup truck. I was probably going about 70 km/hr (40 miles/hr), he must have been doing about 120 km/hr (75 miles/hr).
So we both stop, I'm freakin' out because I almost made it home and some
meatball friggin' hit me while I was moving. I get out of my car to get his info, then he TAKES OFF!!! Some guy behind me saw the whole thing and chased the truck through part of town before he lost him, but he came back and gave his statement to the police. Not like that did much help b/c the cops never did get back to me with any leads.
I always wondered if I had been hurt in that accident if the cops might have done something. Get one more drunk/stoned driver off the roads and away from me.
Worst thing was, I had just decided to go with a cheaper monthly insurance rate, which means you pay a bigger deductible if you're in an accident. My cheap deduction package had expired 10 days before!
UGH! You should tell someone what you saw. I'm sure if you went to the police they'd have to keep your information confidential.
I've been the person on the other end. After that accident, both my FMIL and I were driving around town for weeks looking for black pickups with red paint chips on them...