The american institute for public safety defines the aggressive driver as a person who drives with a lack of courtesy and creates dangerous situations on the road. we describe those types of people as:

I believe the answer is: selfish

The driving violation that initiated by aggressive drivers have the potential of causing harms to others that might lead to death.
Due to this disregard of other people's well being and the pain that it could cause to their friends/families, it is easy to describe aggressive drivers as selfish individuals.