*3.1. Route Variables*

We do not need to know all details of the route but must know any property which influences the nine TCO variables. In this TCO model we selected to base the route description on the time it takes to drive a trip rather than how long the route is, since the required number of buses and driver time are both directly determined by the time required, rather than the distance driven. The route distance is also an input parameter, but most calculations are made based on analysing time. Then, only a few results are translated into driven distance when it is needed to calculate the TCO variables. The route properties are independent of the used timetable.

The main route variable is the net time it takes to drive one trip, which can vary over the day. In our model, we have different trip times in the off-peak period (*T*TripNetOffPeak), in the peak period (*T*TripNetPeak), and during the evening (*T*TripNetEvening). We also need to know the time to drive from the depot to the route or back from the end stop to the depot (*T*PullInOut). For simplicity reasons, we assume it to be the same time for both end stops. This is often not the case, but the given value can then be the average time for the two end stops. To determine the driven distance, we also need parameters for the trip distance (*l*Trip), and the distance from depot to the route's end stops (*l*Depot). If needed, the trip length and net trip time can be used to calculate the average speed of the bus.
