Is it permissible to combine the Dhuhr and Asr prayers before departing the city for the mentioned distance, due to the absence of a safe place to pray along the way?

Prayer in a car is not valid unless it is impossible to pray outside of it, or there is certain knowledge of a significant harm. In such a case, one prays in the car according to their ability, then repeats the prayer as a precaution upon returning home or to a safe place.