It was only about 15 or 20 years ago cities started designating hazardous material routes. Before that trucks and trains would regularly haul the most dangerous things imaginable through some of the most densely populated areas on the map.
On the odd occasion a hazardous cargo will miss their designated route. One of my alma maters administers
this place, which meant that more than a fair amount of explosive material got trucked in. The hazardous material route reached well out away from town and it was on occasion a pleasant evening's run.
One night I was walking back from my classroom building across one of the gated streets - Tech is a "gated campus," for whatever reason gates were closed across some roads at night - and there was a semi parked up next to the gate with absolutely no way to turn around. Being a helpful sort of chap, I walked over to see if I could make a phone call for the driver to get the gate unlocked. Lo and behold, the trailer had "explosive" placards all over it, with my house (and a lot of other folks') a mere hundred meters away.
And the driver was just standing there, smoking a cigarette. Sometimes you just gotta laugh.