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.
