Need some help finding a story.

I'd appreciate some help finding a story. Unfortunately, I can remember very little about it. When it starts the MC's sister is moving away to start college. She leaves in a vehicle with her parents, following in a (truck?) As they are traveling through (Atlanta?), they are involved in an accident. The MC is following them on APRS (Automatic Packet Reporting System). They appear to remain in the same position for an extended period of time.

This is as much as I can dredge up from my memory. I would greatly appreciate it if anyone could help me find the author/name of the story.

Thank you,
Rachel Anne