There are 4 lanes. 2 right for leaving the Autobahn, 2 for driving in the direction Seevetal.
Magic Earth told me i should use the right lanes, which was wrong.
How can I look up, if openstreetmap shows the right direction?
There a several crossing, which tell half left instead of straight.
Is this a openstreemap error? How can i correct it?
I assume you came down the A255. The pieces of the autobahn that hold the lanes tagging are: https://www.openstreetmap.org/way/190594204 and https://www.openstreetmap.org/way/485748074. You see the key turn:lanes=slight_left|slight_left|slight_right|slight_right. That lists the direction of the lanes from left to right. It’s a bit irritating that it says slight left for the two left lanes instead of straight. But anyway Magic Earth should be able to sort that out. So I would say the problem lies with the app not with the data.
By the way: If you are German speaking feel free to use the German sub forum which is more frequented than this one.