Turning place, how big should he be, captains?

Evening. A question that burns on my nails because I am currently planning and unfortunately find on the Internet only real estate offers “with turning place”. How big / must be a place so that you can easily turn around with your truck + trailer / hanger ?? Have an area that so far is only used by Solo truck which will push back when turning into my driveway. However, in future my tenant will deliver with trains, whereby always will be only one vehicle at the area. However, they can not more to push back into my driveway to turn so I have to put on a turning place. The easiest way to explain is to imagine an A4 sheet in landscape format. The driveway takes place on the right side of the sheet and at the top. Coming from there the brummis have to drive to the left long side and then push back a few meters straight (to the ramp). The side (I call it “b” should therefore be long enough so that after the driver’s driveway the train will be After loading (the tractor is loaded sideways, so the trailer is not disconnected) the driver should hit the left side and drive a semicircle to drive out again at the upper right corner. To do this, he also needs space (the short side of the sheet, I call it “a”. The corner to the right of the driveway is of course generously rounded so that the truck can easily get the right turn after the turn. nges shunting since the driveway is also used by other people (PKW) who drive through the place….. Bahh… kling complicated How big should a and b be so that you can get in and out with your ships ?? It’s not really about area consumption (no matter) but about finding a well-functioning solution. I’m grateful for every answer, of course it shouldn’t be too big … every square meter costs money even if we make the substructure for the moment … Thank you!