The Road Traffic Safety Law of the People's Republic of China stipulates the speed limit of 120 km/h (75 mph), effective since May 1, 2004. A minimum speed limit of 70 km/h is in force. On overtaking lanes, however, this could be as high as 100 km/h to 110 km/h. Penalties for driving both below and in excess of the prescribed speed limits are enforced. Some expressways have a lower design speed of . Only motor vehicles are allowed to enter expressways. As of May 1, 2004, "new drivers" (i.e., those with a Chinese driver's licence for less than a year) are allowed on expressways, something that was prohibited from the mid-1990s. Overtaking on the right, speeding, and illegal use of the emergency belt (or hard shoulder) cost violators stiff penalties. Expressways in China are signed in both Simplified Chinese and English (except for parts of the Jingshi Expressway, which relies only on Chinese characters, and some provinces, in Inner Mongolia for example signs are in Mongolian and Chinese, and in XUAR the signs are in Chinese and Uyghur Language which uses Perso-Arabic alphabet). This sharply reduces the language barrier; however, very few toll officials at toll gates speak English. The signs on Chinese expressways use white lettering on a green background, like Japanese highways, Italian autostrade, Swiss autobahns and United States freeways. Newer signage places the exit number in an exit tab to the upper right of the sign, making them very similar in appearance to American freeway signs. Exits are well indicated, with signs far ahead of exits. There are frequent signs that announce the next three exits. At each exit, there is a sign with the distance to the next exit. Exit signs are also posted 3000 m, 2000 m, 1000 m, and 500 m ahead of the exit, immediately before the exit, and at the exit itself. Service areas and refreshment areas are standard on some of the older, more established expressways, and are expanding in number. Gas stations are frequent. 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.