but if the city tow truck lead fails, the first thing they'll do is ask local body shops if there are any leads

Who, the police? Wow, over here unless you had a *good* witness (or several) it would be "well, they say they didn't hit you so you'll have to claim on your insurance. You're not comprehensively insured? Oh dear, here's your crime reference number - close the door on your way out."

Now if you said they were speeding when they drove off...

Gareth