The general rule of thumb is to monitor traffic for "flow of traffic". This means that if the average drivers are doing 5 - 10 over and you are staying with them, you most likely won't be singled out for your speed. We watch for the vehicles that are weaving in and out of traffic and usually doing more than normal traffic flow. One of the speed limits that we can, but seldom do write for is " 1 - 5 miles over posted". They really have to be doing something stupid for this to cause concern.
Colorado does not have a seperate speed for different vehicles. This is good because it keeps traffic flow constant.
Ray, yeah, it does seem as if people are slowing down. Probable reason is that they realize that they are actually saving a little fuel.
ColoradoCop 8)