Signs indicate exits, toll gates, service/refreshment areas, intersections, and also warn about keeping a fair distance apart. "Distance checks" are commonplace; the idea here is to keep the two-second rule (or, as Chinese law requires, at least a 100 m distance between cars). Speed checks and speed traps are often signposted (in fact, on the Jingshen Expressway in the Beijing section, even the cameras have a warning sign above them), but some may just be scarecrow signs. Signs urging drivers to slow down, warning about hilly terrain, banning driving in emergency lanes, or about different road surfaces are also present. Also appearing from time to time are signs signaling the overtaking lane (which legally should only be used to pass other cars). Although most English signs are comprehensible, occasionally the English is garbled.