Cross bordering and waiting time.
Estimated time for cross bordering from Poland to Ukraine
https://granica.gov.pl/index_wait.php?p=u&c=t&v=en&k=w
The time to cross border by car is always lottery but strongly recommend to avoid most busy cross borders like “Korczowa” and “Medyka”.
If you are going to visit Lviv I suggest to go over “Hrebenne” there is no so busy and the quality of the road is ok.
If you need complete overview list of Cross border points you can use this link.