What is the ruling on combining and shortening the Dhuhr and Asr prayers, by performing them early, due to the nature of work and daily travel for a distance of 60 kilometers, and to what extent is the ruling connected to the aforementioned distance?

You must pray the 'Asr prayer before boarding the transportation, and prepare yourself for the prayer before its time. So, when the time for prayer begins, pray it, even if alone, if possible. Otherwise, ask the driver or the responsible party to stop for prayer. If all of that is not possible and you are in need of work, there is no harm in praying in the car if possible, or combine the 'Asr prayer with the Dhuhr prayer by performing them together (jama' taqdim). Strive to find a solution for your situation. As for shortening the prayer (qasr), it is only permissible when traveling.