Why are some roads more notorious for speeding than others?

Question

In my town, there are some roads where the posted speed limit is 45 MPH and if you do that people will zip past you or tailgate. There are other roads with the same speed limit where people will go at or below it. I don't see any law enforcement so that can't be the reason why.

On my drive to and from work, the road I take used to be a two lane road which has recently been expanded to six lanes. It has hardly any traffic on it. The speed limit is 45 MPH but people will do 50-55.

Answer 1

Law enforcement agencies are supposed to periodically do a "survey" and if they find traffic going faster than the limit on a daily basis, and there are no reasons to KEEP the limit low,  such as a nearby school,

residential area with a lot of cross walks etc etc, they will raise the limit.

These surveys are NOT done as often as they should be though.

Answer 2

Roads are not notorious for speeding - it is the idiots that use them!

Answer 3

Well one reason I have is because some spots are "hot" and others are not. Let's say you drive down a rural road, that road probably wouldn't be as "hot" as let's say a street in the city.