I'm actually glad to hear they come on under an overpass! There's an overpass that I often go through in downtown Toronto that's kind of dangerous at times. The traffic gets backed up through it, and on a sunny day, you from bright to dark so fast, it's not always easy to see if there's a car right in front of you. If they have their lights on, it's a lot easier to see them! Especially when they've stopped, and you're still moving. I sure wouldn't want someone ramming my new Murano there..