Modern Roundabouts Require Cooperation to Function
A huge difference in the way roundabout operate in the USA versus in China is that in the USA there is a cooperation between drivers based on a YIELD ON ENTRY rule, where drivers entering a roundabout actually wait for a gap in traffic, and not the other way around. The drivers inside the circle already do NOT stop for other drivers coming in, they don't slow down, they don't give way... the expectation is that drivers inside the roundabout already need to be able to get out easily, or else the whole roundabout is gridlocked. Once a driver stops inside the roundabout, it will gridlock for all movements. The MAIN LANE in the roundabout that just always be free-flowing, is the circle lane(s).
In China, drivers entering the roundabouts sail in and even cut off drivers already inside the circle, and they also exit the roundabout from the innermost lane making a sweeping cut-off maneuver to other drivers in the roundabout, causing them to slow or stop to avoid an accident. This is a capacity defeating behavior.
Typical small Roundabout in Fresno, CA, Feb 2018
Yield on entry is well established. 10 years ago this was not the case as many cars did not yield on entry
Roundabouts in China are not the same as Roundabouts in the USA. 中国比美国不一样
No Yielding at entry...Signals sometimes used at entries... No deflection on entry, etc.
Video Documentary: Navigating a large 500' diam. Roundabout in China, on an electric Scooter 骑电动车的时候 (circa Aug 2015, Fuxin 在阜新市, Liaoning 辽宁省Province, China)
Zhong hua lu 中华路 roundabout. diameter = 500’ . 5 vehicle lanes, 1 bike lane. X-WALKS on 4 of 5 approaches