You're absolutely right: speed makes all the difference.
The state of Montana has no official highway speed limit. They do enforce a "reasonable & prudent" limit, which is somewhere in the 80 - 90 mph range. Forcing drivers into an artificially lower driving speed was killing more people than it saved.
"In 1999, after 4 years of no numerical or posted daytime speed limit on these classifications of highways, outside of urban areas, Montana recorded its lowest fatality rate."
"Research scientists and engineers have long known that there are sometimes unexpected results from changes in public policies. Ironically, the paradox of no posted speed limits and low fatalities is no surprise to the traffic safety engineering community."
"For years, motorists' advocates have used engineering-based facts against artificially low speed limits. They have claimed that by raising speed limits to reasonable levels, accident and fatality rates will actually be reduced. This seemingly wild assertion has been documented by the traffic engineering profession for 50 plus years. This fact-based position has again been proven to be true by the repeal of the National Speed Limit. The nation has recorded the lowest highway fatality rate since such records have been kept."
http://www.motorists.com/pressreleases/montana.html
