Why do Zhengzhou b5 buses open their doors on the left side?

Because the BRT platform on Longhai Road is an island platform (i.e., the platform is in the middle of the road) rather than a side platform (like B1), all B5 and related lines (such as the 1 road) have been gradually replacing their vehicles with left-side openings (there are even a part of the 18-meter articulated buses that are currently being replaced with left-side openings)

Beijing's BRT Line 1 is using this left-side opening method

In addition, all left-side openings have been retained to ensure docking with regular buses during emergencies.

Beijing's BRT Line 1 uses this type of left-side door opening

Additionally, all left-side door openers retain their original right-side doors in order to ensure that they can be docked with regular buses in emergencies and make it easier to stop at regular platforms

The two platforms and door openers have their own characteristics

The advantage of an island-type platform (in the center of the street) is that it has less space on the road for standing, and it can be used to transfer to opposite buses (e.g., buses that are moving in the opposite direction) at the same time. The advantage of the island platform (the center of the road) is that the station uses less road space, and you can transfer to the opposite direction of the car (for example, if you ride through the station, you can ride back from the next station for free), but the same needs to be changed on the vehicle (changed to the left side of the door), otherwise ordinary vehicles can not be used

Side platforms (the kind of B1) advantage is that there is no need to make any changes to the vehicle, all the ordinary buses can also be used to use the platform of the BRT, the disadvantage of it is that it occupies a large amount of road space, and a station needs two platforms.