In Minnesota once in awhile you will see roadside memorials (crosses, flowers, stuffed animals etc...) where someone has died from a accident. In South Dakota all over the state they have signs that say THINK with a X on them. I think it is a good idea, there is one along the highway about 20 miles from where I live a grandpa, grandma & grandson were killed when a semi truck slammed into them. The family has a really nice memorial along the road, handmade crosses, flowers they have kept it up for about 10 years
http://www.roadsideamerica.com/rant/descansos.html