Korczowa-Krakovets border crossing
The Korczowa-Krakovets border crossing connects Poland and Ukraine near the city of Lviv. On the Polish side, it is the starting point of the A4. However, a portion of the motorway between Jarosław and Rzeszów is still under construction.
Walking across this border is not allowed.
As with the other nearby border crossings, waiting times can be very long here.
The border police will not let you cross on foot. Finding a ride across the border can be very hard, coming from Ukraine at least, as people are quite afraid of problems you might cause. Everybody wants to make it through as fast as possible and will likely see you as a possibly delaying factor, or might even think you're smuggling something. Mohit had no luck talking to drivers, most of whom outright refused to talk to him.
The border guards can be unfriendly, but if you are persistent and bother them long enough they might tell drivers to take you, increasing your chances drastically.
It may be better to choose the Medyka-Shehyni border crossing instead, where walking across is possible. There is a lot of traffic at all border crossings in the area, so your chances of finding a lift going further into Poland don't really depend on where you cross. Drivers don't seem to base their decision which crossing to take on the shortest distance or best connection to the motorway (A4), but rather on traffic or past experiences.
Into Poland (A4)
You can start thumbing right after the border, cars can stop there easily.