[tasdrouille]

Shovel,

Remove the speedsters and the average speed of traffic goes down, slowpokes still drive the same speed they have always been driving and crash rates go do. The same thing happen if you remove the slowpokes, crash rates go down, only more people die due to high speed fatal crashes.

So which came first, the speed deamon or the slow poke?

I don't think you can draw conclusions like that from the graph alone.