Loving the Personal Space
Only those who have more than one kid can truly understand how terrifying the long road trips can be with those little humans. Despite how long the journey may be, more than one child in a car can always succeed to start a fight somehow or some other mess.
Dealing with personal disputes of your kids while driving means you have to take your eyes off the road and that is not acceptable at any cost. What you should do instead is give each kid her/her personal space in the car by adding a cardboard wall between each one.