Thanks for the kind words, all. It was definitely scary. MrsG called right after it happened, and she was obviously shaken up. Fortunately, the accident happened in the rear view, so LowerCaseG didn't see any of the actual event. Everyone is okay, but that was far too close a call for my taste.
One amusing anecdote from the whole deal: (Note: LowerCaseG, like most boys his age, thinks firetrucks are awesome.) MrsG must have called me as soon as she was able to pull over after the accident, because she said the only first responders on scene were the cops involved in the chase. While we were on the phone, I could hear sirens as other cops, paramedics, firetrucks, etc. were arriving. In the middle of my wife tearfully recounting this horrific wreck that has barely missed her and our child, I hear sirens followed a little voice yelling "firetruck!!! MAMA!!! IT'S A FIRETRUCK!!!"