Nah I’ve definitely done a quick heel-toe walk across an area to get a ballpark of distance. Along with basically any other body part I could reasonably use to measure something when I don’t have a tape measure on me at that moment.
I’ve also previously measured and I know that for example my bare foot is about 11 inches long heel to toe and that my shoe makes it about 12. I could do exactly the same thing with metric.
I might be wrong in this. My understanding is that it is flammable, but not when it’s “solid” if that makes sense. That a fire would have to be on it and burning hot enough for long enough to start melting the tar then that could burn. But the asphalt itself isn’t likely to just catch fire from a lighting strike or something and just continue to burn.