Ateenage driver who has a fender bender while texting learns to discontinue his habit of texting while driving. in this case, his fender bender is a

an example of negative reinforcement. He will remember the fender bender and it's trauma and repercussions when he considers whether or not to text while driving and will refrain from this behavior.

In this case, his fender bender is a NEGATIVE REINFORCER.
A reinforcer refers to a stimulus that increases the probability that a specific behaviour will occur. A reinforcer can be positive or negative. A positive reinforcer adds consequences which reward the behaviour while a negative reinforcer remove a negative consequence in order to increase the probability that a behaviour will occur. In the question given above, the fender bender [minor collision] is the negative reinforcer which increases the probability that the teenager will not text again while driving.