The Brisbane Integrated Transport Study required new modelling software to be written, as previous software was poor at modelling public transport, inflexible, too slow, and unable to handle the huge problem size of the new model, which contained 2500 zones and thirty-five market segments. Peter developed a new approach to transport software, based on a command line based transport modelling computer language. The resulting package was five to ten times faster than other packages, and could handle much larger problems, in part by compressing and decompressing model data on the fly. It had a very sophisticated multiple-path public transport assignment algorithm, which allowed multiple access modes. The software was very flexible, easily automated and could be tied to other software tools such as Geographical Information Systems.