Median dividers found on a highway. Sometimes made out of concrete or perhaps a cable running along the length of the median. A structure that does not permit a copper to drive from one direction of lane traffic to another direction of lane traffic. This allows motorists to speed without fear, knowing that a cop passing by going the other direction cannot whip it around to pursue.
Wyatt: I love the beltline you can straight haul ass!
Dumb Greek: How is that?
Wyatt: Mother fucker's got cop blockers the whole way round.