More than of all crashes occur at speeds less than 40 mph?

I believe that the statistic you're looking for is "Half of all car crashed happen at less than 40 miles per hour." That's probably true, because more accidents happen in the city than on the open highway, and in the city, you're more likely to be driving slowly. The more SERIOUS accidents happen at higher speeds, and often involve alcohol, but these can happen in town or on the highway.