Changes

If you are generally not that lucky thumbing down cars and you would like to start your jouney straight at the Highway, the easiest option is to travel to Rasthof Teufelstal which is located at the A4 approx. 15 km east of Jena. From here it should be no problem to ask people for lifts east or west. To get there either take the local train from Jena West towards Gera and get off at "Papiermühle". From here it is a (scenic) 3 km hike first east along the valley and then south to the small village of Bollberg. From here you either cross the fields directly to the Rasthof if heading west or cross the Highway (walk towards Mörsdorf after Böllberg) and head east at the other side for hitching east.

The A9 as a main north south magistrale passes Jena aprox. 25 km in the east. As it is probably difficult (though still an option) to use the above described options to start on the A4 and then change on the A9 you are probably better off aiming at the A9 straight away. You could either travel to the petrol station "Hermsdorfer Kreuz" straight on the highway, start at a petrol station in Eisenberg or hitch towards the A9 on local roads.