It’s probably the number of meshes. So what I did now, is to setShaderAuto only for the floor nodes, so all road and road markings etc that are on the floor. It’s especially these that don’t look good with per vertex shading because the polygons are often not small enough. For all other meshes I use per vertex shading for the Spotlight. And now the framerate is good, so I think this is solved now.
Thanks.