There are several ways to get out of the city centre and onto the main highway. If you stop a car that is not going a long distance, then it is best to aim for the Mahmutbey toll booths in the northwest of Istanbul where the E80 really begins.
==== Test option - Ispartakule Park Area North ====
Strictly speaking, pedestrians are not permitted here; if a bored traffic police officer asks you to leave, but ignore him and feign misunderstanding, and walk a few metres away and thumb.
==== Second option ====
Hitchhikers experience 2014: Not the best place to stay, eventually we got a ride of a guy that wanted to help us, but after 2 hours going around Istanbul, left us in a much worse place close to the airport. So be strict with where you want to go. Ask at least for the toll.
==== Third option ====