Since the number of trials is not fixed, an inverse binomial distribution is used.
For each car, there are only two possible outcomes, either they use a blinker during lane change, or they do not. The probability of a car using a blinker during lane change is independent of any other car, which means that the number of cars that do not use a blinker during a lane change is a binomial variable.
A similar problem is given at https://brainly.com/question/25644451