This is easy... have you even made an attempt? Start with the use case diagram and identify your actors. Then identify the individual use cases, what are the different processes that must occur? After identifying those, map your actors the the use cases that they have a relationship with.... Come back after you've accomplished this!!
yasallam...If you have no interest in learning this on your own then you should focus your efforts on becoming a toll booth technician that requires no thought or skill set. Do your own damn homework!