For the last several weeks my battery indicator light has been going on when I pass through a highway construction zone. It goes off once I leave the zone. It's about 25 miles from my home. I've taken other trips of more than 25 miles outside of that area without incident. Does this sound like electrical interference or a faulty alternator?

I'm planning to take it to Autozone to have the alternator checked as soon as the ice clears from the road (tomorrow?) I have a road trip to Jacksonville planned for next week and would like to get this resolved now instead of on the road.