Why were mexicans on the side of the road followed by a flaming torch?

For about 10 miles in town today, Mexicans were spaced out every few yards. They were dressed in white shirts and blue sweat pants. I thought maybe the bus had a new route but then, going out of town, was a white van followed by a Mexican running with a flaming torch. This was down a major highway and that van was going extremely slow, not to mention the FIRE. After I passed it all there was a cop going in that direction. My mother suggests that it could have been a celebration or cultural ritual of some kind. Have you ever heard of anything like this? Trust me, my news won’t cover it and I just can’t figure this out.