Bus journey time comparisons are conducted in a similar fashion to car based journey time comparisons, although without the need to conduct actual surveys. Bus timetables are used as a proxy for the journey times through the road network and compared against the equivalent journey times produced by TMfS for the same bus services. It is assumed that bus operators produce timetables with a strong understanding of congestion hotspots and peak vehicle requirements. In general, bus journey time surveys tend to show that TMfS models bus journey times well.