I do everything I possibly can to never stop my car under a bridge, especially here in Northern California. The chances of catastrophe while I’m under a bridge are extremely small, but I really don’t like the idea of being squashed like a bug under a boot.
Same with us, friend. My wife and I get nervous under an overpass, look for a way out if it should collapse. In 1989, one day before the Loma Prieta Quake, we had driven on the same freeway overpass in Oakland that collapsed and squashed cars. The what-if scared the heck out of us, but for one day difference. We try to stop short of overpasses, then scoot through quickly. As you say, extremely remote chance, but it's human nature to think of what could happen.