How to I add a closed gate that prohibits cars to pass?

In my neighborhood there are two gravel roads that meet each other. in a point,. At that point there is a locked gate that prohibits cars from pass but bicycles and pedestrians can pass. How do I add that gate into the map so the GPS does not try to make drivers pass through but choose a different 100m longer way through a parallel road?

(its a circus every summer. Its in an areas with many typical summerhouses that are for hire and sometimes for sale which makes many people get stuck at the gate and try to turn around in this very narrow gravel road with deep ditches at both sides)