I live near a rail line and a secondary feeder highway off the main west coast Interstate.
Knowing which way the wind blows could be crucial to an escape plan. Here, the prevailing wind is from the west, but in the mornings it often blows from the east, and other times it comes from the south.
I haven't done it, but I've often thought that a simple weathervane could be very useful in such a situation. It would be really stupid to race TOWARD a leaking chlorine tank...
Sue