Abstract
In the literature, two different models have been used to compute link travel times in dynamic traffic assignment (DTA), and elsewhere we investigated how these are affected by discretising the link length. Here we consider discretising time as well as space (the link length). We vary the discretising of time with spatial discretisation held fixed, and vice versa, and also vary both together. The results show that “coordinated” discretisation is usually the most efficient in approximating the limit solution (continuous time, continuous space) and, even when it is not the most efficient, it has other advantages. The results have implications for algorithms for DTA and for the choice of discrete versus continuous time models. For example, refining the discretisation of time (without refining it for space) can make the solution less accurate, so that in the widely used whole-link models (i.e. without spatial discretisation) it is more efficient to use the largest feasible time steps, close to the link travel time.
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Carey, M., Ge, Y. Efficient Discretisation for Link Travel Time Models. Networks and Spatial Economics 4, 269–290 (2004). https://doi.org/10.1023/B:NETS.0000039783.57975.f0
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DOI: https://doi.org/10.1023/B:NETS.0000039783.57975.f0