I have 120 bus stop locations with road network and number of students. I prepared the network dataset, but i don't know what to do next to find out optimum number bus routes which required to connect the bus stops based on the number of students using ArcGIS 10.1.
It depends on what kind of result you expect to get. From your question, it may seem as VRP would be the best analysis type. You will define during the VRP analysis:
- each bus capacity (number of students it can take);
- what time of the day each bus can start driving and what time will they stop driving;
- maximum driving time for each bus (if you have any legal restrictions);
- locations of their parking place where they start and end.
- hard/soft geographic zones for which they will to do their driving (if any).
Start simple by taking a couple of buses and building a workflow the results of which will make sense to you. Then build it up including more details and more buses.
Consider going through this tutorial, which I found a couple of years ago very useful:
The output result of the VRP (basically what you would want) is the number of buses (with their unique IDs), what routes they will follow, what time will they start/end their driving and optionally how many students they will transfer.