As you drive through the southwest, particularly Arizona, you occasionally see a cross beside the road. There are two significant details: they are always in a place that it easily accessible and hard to wreck a car, and they might appear alongside a new highway as soon as it is opened to traffic. So they have nothing to do with traffic fatalities. A lot of people assume these are memorials to loved ones, and that may be true in some cases, but they are also a carryover from a tradition that is at least 1200 years old.
The Apache tribe lives here, and there, and other places. Apaches often wandered around the state and murdered people just to stay in practice. After the survivors had recovered, they would bury their dead and erect a cairn, a pile of stones, to commemorate their losses. Then they would return to the place every year to clean it up, renew family ties and retell the old stories.
When the Catholic missionaries took over, the tradition was changed to crosses instead of cairns, but otherwise no change. As progress progressed, the crosses were made of used lumber, then new lumber, then new lumber painted. Now they tend to be made of PVC pipe fittings, or sometimes wrought iron.
As for the Apaches, they stopped murdering people about 1965. It seems they really preferred sneakers to their traditional moccasins, and they eventually realized that their suppliers didn't want to deal with murderers.
