Dear Readers,this is the second 2021 issue of our journal (No. 66). We are slowly seeing the world normalize after the COVID-19 pandemic, and we look forward to a complete return to our usual routines and to meeting again at conferences, seminars and research internships. Let us all hope that this will come true soon.Research results and author opinions are presented across seven articles in this issue, which are sum-marized in three thematic groups: Civil Engineering and Transport, Mechanical Engineering and Economics, Management and Quality Science.
With kind regards, Izabela Dembińska (Editor-in-chief)