[andrewla]

Although I agree that this is certainly true, I cannot vouch for its historic truth. It is possible that the vast reduction in the murder rate is primarily due to the fact that vehicle accidents are (no longer) considered murder, rather than any actual reduction in violent crime.

Not stating this as fact -- I haven't even done my homework to look at vehicle-related deaths over time -- but as motivation for the possible blind spot pointed out by thrownaway2424. Historical crime data is notorious for this because statistics are gathered by law enforcement and have a subjective aspect based on the time that they are gathered.

[mikeyouse]

Motor vehicle deaths, especially when corrected for miles driven or total population, have dropped precipitously:

http://en.wikipedia.org/wiki/List_of_motor_vehicle_deaths_in...

Murder, aggravated assault, rape, robbery, etc. are all down across the board, in some cases by more than 50% in 20 years:

http://www.fbi.gov/about-us/cjis/ucr/crime-in-the-u.s/2012/c...

There are always some subjective decisions on data reporting, but that's much more prevalent in data comparisons between countries rather than over time within a single country. The FBI has been very consistent in their reporting.