Laws may exist, but they are almost universally ignored. When asked, bicyclists in Shenzhen seem only to be aware of the law that makes electric bicycles illegal except for licensed delivery or tradesmen, but nobody worries about it because the cops almost never stop you. The unwritten rules of the road are roughly as follows:
Ride on the right, unless there is a truck, car or bike, delivery trike or motorcycle heading toward you on the wrong side of the street. This happens every 2 minutes or so on most city streets. When this happens, ride either on the sidewalk, the middle of the road or on the other side of the road facing traffic. There are seemingly no laws or conventions about which side of the road or sidewalk to ride on. Approximately half of the bicyclists ride the wrong way on one way streets or in the lane reserved for oncoming traffic. The most common practice for turning left on a 2 lane street is do so from the wrong side of the road, against oncoming bike and vehicular traffic, forcing your way around the oncoming cars until you find an opening, then turn left into oncoming traffic and fight your way across onto your own side of the road. The rest of the people use a less predictable approach. Bicycles (and pedestrians) never have the right of way. Motorized vehicles never the yield the right of way unless it is almost certain that the cyclist will be killed. In fact, if a motorist or motorcyclist thinks there is any chance that allowing you to pass would require them to slow down, they will deliberately overtake you and cut you off. On a typical 20 minute commute, this will happen at least 2 or 3 times. There are also no conventions about what to do when two cyclist meet head-on on a sidewalk (where about 70% of cyclists travel). An equal number pass on the right as on the left, with frequent collisions.