The End of Travel Time Matrices? Or: Why We Should Use Individual Travel Times

Abstract1 To reduce inaccuracies due to insufficient spatial resolution of models, it has been suggested to use2 smaller raster cells instead of larger zones. Increasing the number of zones, however, increases the3 matrix size of skim tables. Those become difficult to create, to store and to read, while most of4 the origin-destination pairs are calculated and stored but never used. At the same time, such ap-5 proaches do not solve inaccuracies due to lack of temporal resolution. This paper proposes to store6 and process travel times at the finest spatial resolution possible (at x/y coordinates) and a highly de-7 tailed temporal resolution. The approach is tested in the context of an integrated land use/transport8 model (ILUT) where travel times affect, among others, household relocation decisions. In this pa-9 per, person-level individual travel times are compared against traditional skim-based travel times.10 It was shown that skim-based travel times fail to capture the spatial and temporal variations of11 travel times on a microscopic scale. While skims provide acceptable averages in the case of car12 travel times if a dense network and small zones are used, transit travel times are heavily affected by13 temporal and spatial aggregation. When looking at travel-time-dependent relocation decisions in14 the land use model, transit captive households tend to react more sensitively to the level of service15 in transit when individual travel times are used. The results suggest that individual travel times can16 improve the spatial and temporal accuracy of models.     «

Abstract1 To reduce inaccuracies due to insufficient spatial resolution of models, it has been suggested to use2 smaller raster cells instead of larger zones. Increasing the number of zones, however, increases the3 matrix size of skim tables. Those become difficult to create, to store and to read, while most of4 the origin-destination pairs are calculated and stored but never used. At the same time, such ap-5 proaches do not solve inaccuracies due to lack of temporal resolution. This paper...     »