In an observational study, the researcher observes, notes and record the an occurrence of events which are due to the existence of a condition, test, risk factor, such that the experimental units are apparently out of the control of the researcher, or there are no researcher intervention in the study, due to either physical constraint or laid down ethics.
In the question, the researcher observes to determine the the number of people that run a light through pre recorded traffic video providing a physical restraint which makes it an observational study.
