Darmstadt is a city in the German Bundesland Hessen. Take Bus 5515 at the Luisenplatz in the direction of Erzhausen, until the "Am Rotböll" stop. From there you walk a bit back to the highway, go right to the asphalted street parallel to the highway to the service staiton "Gräfenhausen". Walk 2 km through the woods or try to hitch a ride from there to the service station. The station is the best in the region, for going any direction.