Very hard homework need help please help

there is a crossroad build in city.This crossroad will degrade some traffic jam.You’are the software engineer in charge,and gonna develop complete ligthing system for this crossroad.The traffic light will let cars flow in clockwise ,namely the car on the right will have the priority as the traffic law states.By the way,crossroad includes crosswalks for padestrian.İn each 60 seconds ,lights let cars in each side go thru.And at the end of every turn,light will let padestrians for 15 second.
… the system shall either let operator to put cars to the crossroad or it randomly put cars and padestrians.System shall support both modes.
…the system shall run a simulation at least for 5 turns.
…the system shall let operator to fast-forward simulation 1x,2x,4x,8x step ,so operator will not have to wait all the tşme to end.
a)Draw complete use-case diagram
b)Draw complete static class diagram

It looks like two actors of “Time” and “Operator” invloved here. In my company, we handle it following the procedures described below:

1.Make the requirement list from the requirement.
2.Find out actors and use cases.
3.Make event flow descriptions and activity diagrams of use case.
4.Use RequisitePro or traceability table to ensure the coverage.
5.Make SRS.

Once you finish use case model, analysis model and design model can be worked out accordingly.