I noticed a issue with the overtaking logic while testing the display testing I posted in this thread (https://forum.simutrans.com/index.php/topic,18073.msg189362/topicseen.html#msg189362).
The current specifications of simutrans do not allow overtaking next to an intersection.
So I used to think that at least the bus stop must be at least 2 squares away from the intersection for the loading_only_mode(Overtake stationary only) to work properly.
But as you can see in this image, it doesn't work in some directions. The yellow-green tile indicates that the bus stop is in loading_only_mode(Overtake stationary only mode).
It cannot overtake from the north and west. We need one more tile on the front side.
It's hard to meet the conditions of being able to overtake in the city, so it reduces the value of this feature. Also, when the camera is rotated, the change of overtaking ability will occur. This means that the rotation of the camera is not correctly supported.
(halt mode was an error in loading_only_mode. Corrected the expression)