Yeah swamp lights are either oxidation of phosphorus (which will glow in air) from various sources, or it's gasses bouncing lights around from things like cars or campfires. I actually like them a lot. They're pretty neat and show up in a lot of the world. The myths about will-o-the-wisps and Jack o' Lanterns come from swamp lights and it's also why ghosts in Japanese folklore are often presented as a floating ball of fire.

My parents never took us out to that one stretch of road again. There were so many rumors about who was out there. The other kids tried coming up with supernatural explanations, like we saw ghosts or demons. At this point as an adult I'm pretty sure it was Klansmen, a weird meth group/cult, or some combination of the two.