While exiting Marfa, heading east, the speed limit from inside the city at 30 mph changes to forty mph. If you accelerate above 30 mph before you actually reach the speed marker of 40 mph, city cops are waiting on outskirts of city, just around a turn that hides their vehicles at night. Enforement is strict, as they take the 40 mph marker to be exactly the point where the higher speed should start. The speed limit goes from 40 to 55 mph right after that, so drivers expect to naturally accelerate as they leave the city. City cops establish their vehicles at a point where drivers passing thu in the evening do not see the city cops around a turn, and they point their radar guns at the point just beyond the higher speed limit (aiming at the lower speed limit area) to “catch”” drivers leaving the city. City cops have “”courtesy”” envelopes with fines already prepared for all traffic citations.”