WP I see your point, and to some extent I think we as a society just accept the traffic deaths as a cost of dong business, however there are substantial resources expended on trying to reduce traffic deaths, including PSAs, traffic law enforcement (crappy as it is) development of auto safety devices and the like. I'd guess, that if all costs various auto safety initiatives, research and development were summed they would vastly exceed the amount spent on suicide prevention.
Would be some interesting comparisons to be made for sure. My personal observation is the amount spent on the prevention of any death/injury is more related to the strength and attractiveness of the lobbying organization than to the actual number of deaths or death rates.