Speed Limits are as follows:

30 km/h (19 mph) on city roads where there is only one lane per direction, 40 km/h (25 mph) on China National Highways;

up to 70 km/h (43 mph) on city roads where there is a major road with central reservation or two yellow lines, 80 km/h (50 mph) on China National Highways;

100 km/h (62 mph) on city express roads;
120 km/h (75 mph) on expressways.

 

Tips for the Speed Limits:

Tolerance is generally around 10 km/h (6 mph). Some expressways may have tolerance set all the way up to 20 km/h (12 mph); however, anything around 15 km/h (9 mph) to 20 km/h (12 mph) over the stated speed limit is relatively high risk.

Speed traps are conveniently identified with the characters "lei da ce su qu" (radar speed check zone) or "qiao su she xiang" (speeding detection camera).

 

Penalties for exceeding the speed limits are as follows:

up to CNY 200 for excess speeds over 10 km/h but under 50% of the speed limit. Example: if driving at 100 km/h (62 mph) in a 80 km/h (50 mph) zone.
up to CNY 2,000 and possible loss of license for excess speeds over 50% of the speed limit. Example: if driving at 190 km/h (118 mph) on a 120 km/h (75 mph) expressway.