While I sympathize with one's grief..I am at a loss to understand the roadside markers. Since it is Christian doctrine that ..' to be absent from the body, is to be present with Jesus at home with Christ.... I am surprised to see rather prominent Christian families erecting these memorials..
I guess it is their business, so long as the memorial is not constructed of substantial material which may prove hazardous to others....the wide shoulders of the highway are there for a reason.
Understanding people's grief, perhaps highway departments are reticent to do away with these displays. I guess if I had some on a highway I was responsible for, if it fell into disrepair and wasn't being maintained well..then I would remove it.
If this practice is to continue unabated, in 20-30 years some of our highways would have little clear shoulders left!