I drive slower than traffic in town all the time.
One quirk that irks traffic cops is to drive in the number one lane when there is ample opportunity to move to lane # 2. It's the law on open suburban multi-lane boulevards and on all
"Inicio Tramo Cargo de SCT"
Start of the federally enforced PFP "sections (tramos)" outside of incorporated towns. Also includes multi-lane toll roads.
One other quirk and any Mexican can tell you this is a no-no, don't look at the face of of a Mexican cop if he's on foot or in a car. It's some weird challenge or something. I tried it just to be cute about forty years ago - she came roaring down the steps of some public building blowing her whistle and holding her baton aloft. I laughed, slowed down and led her for a running block before dusting her off and heading for the ferry terminal. Would not be smart in today's cell phone age.