Kelebia-Tompa border crossing
The Kelebia-Tompa border crossing links Hungary to Kiskunhalas city, and Serbia's Subotica city.
The crossing is situated on the 53, which is a local highway to Kiskórös from Subotica. It is not very common border-path, because of that there is almost no traffic except the trucks. There is no walking path for people, however you are allowed to pass through the gates of light cars. Because there is no car traffic, it's easy and fast.
Because there is almost no traffic it won't be easy to hitchhike from there (but still possible!) and normally will depend only on your luck.