Think about it for a second: Which hand do you use to open the door of the car. It doesn’t matter if you are the driver or the passenger.
If you drive on the right side of the road than you would normally open the door with your left hand. In case you drive on the left than with the right.
Is it the correct way to open the door? It is definitely the most convenient way as it takes no effort. Also it is not the correct way. It is correct in a way that it makes sense and it is the easiest,but it is not really safe.
The correct way to open the door is called : “The Dutch Reach” .
This technique is very simple and also taught in the driving schools as well.
It is based on an assumption that most of the people not even looking in the side-view mirror to check if anything is coming.
So the technique is very simple: you just open the door with the other hand forcing your body to turn in the process and you will be able to see if there is a bicycle or car coming.