examples are long acceleration lanes on motorways and large stopping sight distances at intersections increased letterheight and retroreflectivity of street name signs etc for intersections with traffic lights errors in giving way and any resulting crashes can be prevented by a regulation that does not allow traffic that can collide to have green light simultaneously roundabouts have the required qualities for older drivers eg left turns are eliminated fewer decisions have to be made because of oneway traffic and yieldatenter lower speeds allow for more time to decide and act staplin et al they reduce crash numbers and as a result of lower speeds crash severity