I live in a suburb of Memphis, and work in another farther out suburb, with only rural roads in between. It's a rather boring, and long commute, actually. Most roads have 35 to 45 MPH limits. However on this road shown in the link, which is 25 MPH, I was actually doing 24-25 one day and STILL had a motorist gun their engine and downshift to zoom around me.
http://goo.gl/maps/xyjaz