TY - JOUR
T1 - Extending travel-time based models for dynamic network loading and assignment, to achieve adherence to first-in-first-out and link capacities
AU - Carey, Malachy
AU - Humphreys, Paul
AU - McHugh, Marie
AU - McIvor, Ronan
PY - 2014/7/31
Y1 - 2014/7/31
N2 - An important class of models for macroscopic dynamic network loading (DNL) and dynamic traffic assignment (DTA) is based on treating link travel times as a function of link occupancy. However, these models suffer from some problems or deficiencies namely (a) the link outflows can violate first-in-first-out (FIFO), (b) the link outflows can exceed the link outflow capacities, (c) the link inflows can exceed the link inflow capacities, and (d) the link occupancies can exceed the link occupancy capacities. In this paper we introduce methods to overcome each of these problems.To remove problems (a) and (b) we extend the link travel-time model to better reflect behaviour when traffic flow is varying over time. To remove problems (c) and (d) we introduce more substantial changes in the model, to introduce capacities, spillback and queues compatible with the model. These extensions strengthen the realism, behavioural basis and usability of the link travel-time model and the DNL and DTA models that are based on it. They have no obvious adverse implications or side effects and require little additional computational effort. The original model is a special case of the new/extended model: the above extensions are activated if and only if any of the problems (a)–(d) arise, otherwise the new model reduces to the original model.
AB - An important class of models for macroscopic dynamic network loading (DNL) and dynamic traffic assignment (DTA) is based on treating link travel times as a function of link occupancy. However, these models suffer from some problems or deficiencies namely (a) the link outflows can violate first-in-first-out (FIFO), (b) the link outflows can exceed the link outflow capacities, (c) the link inflows can exceed the link inflow capacities, and (d) the link occupancies can exceed the link occupancy capacities. In this paper we introduce methods to overcome each of these problems.To remove problems (a) and (b) we extend the link travel-time model to better reflect behaviour when traffic flow is varying over time. To remove problems (c) and (d) we introduce more substantial changes in the model, to introduce capacities, spillback and queues compatible with the model. These extensions strengthen the realism, behavioural basis and usability of the link travel-time model and the DNL and DTA models that are based on it. They have no obvious adverse implications or side effects and require little additional computational effort. The original model is a special case of the new/extended model: the above extensions are activated if and only if any of the problems (a)–(d) arise, otherwise the new model reduces to the original model.
KW - Travel-time functions
KW - First-in-first-out
KW - Link flow capacity
KW - Spillback
KW - Dynamic network loading
KW - Dynamic traffic assignment
UR - https://pure.ulster.ac.uk/en/publications/extending-travel-time-based-models-for-dynamic-network-loading-an-6
U2 - 10.1016/j.trb.2014.04.002
DO - 10.1016/j.trb.2014.04.002
M3 - Article
SN - 0191-2615
VL - 65
SP - 90
EP - 104
JO - Transportation Research Part B: Methodological
JF - Transportation Research Part B: Methodological
ER -
