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Network design through sensitivity analysis and singular value decomposition
No full textSan Miguel, Portuga
Maximal bandwidth problems: a new algorithm based on properties of periodicity of the system
No full textAppendix 7A - The simplified theory of kinematic waves based on cumulative flows: application to macroscopic link performance models
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Advanced pricing and rationing policies for large scale multimodal networks
Get PDFThe applying of simplified schemes, such as cordon pricing, as second-best solution to the toll network design problem is investigated here in the context of multiclass traffic assignment on multimodal networks. To this end a suitable equilibrium model has been developed, together with an efficient algorithm capable of simulating large scale networks in quite reasonable computer time. This model implements the theoretical framework proposed in a previous work on the toll optimization problem, where the validity of marginal cost pricing for the context at hand is stated. Application of the model to the real case of Rome shows us, not only that on multimodal networks a relevant share (up to 20%) of the maximum improvements in terms of social welfare achievable with marginal cost pricing can in fact be obtained through cordon pricing, but also that in practical terms rationing is a valid alternative to pricing, thus getting around some of the relevant questions (theoretical, technical, social) the latter raises. As a result we propose a practical method to analyze advanced pricing and rationing policies differentiated for user categories, which enables us to compare alternative operative solutions with an upper bound on social welfare based on a solid theoretical background. (c) 2005 Elsevier Ltd. All rights reserved
Comparing marginal cost pricing with toll cordon policies for large scale multimodal networks
No full textIn this paper, the possibility of applying simplified schemes, such as cordon pricing, as a
second-best solution of the toll network design problem is investigated in the context of a
multiclass equilibrium on multimodal networks with elastic demand. To this end a suitable
equilibrium model is presented together with an efficient algorithm capable of solving it
for large scale networks in quite reasonable computer time. This model represents an
implementation of the theoretical framework proposed in a previous work on the toll
optimization problem, where is stated the validity of marginal cost pricing for the context
at hand. The application of the model to real cases shows, not only that through cordon
pricing a relevant share of the maximum savings achievable with marginal cost pricing
can be actually obtained, but also that in practice rationing is a valid alternative to road
pricing which obviates to some of the relevant questions (technical, social, ...) that the
latter raises. As a result we developed a practical method for analyzing advanced pricing
and rationing policies, which enables us to compare different operative solutions with an
upper bound based on a solid theoretical background
A within-day dynamic traffic assignment logit model to multimodal urban networks
No full textIn this paper, with reference to congested multimodal urban networks, within-day dynamic
traffic assignment is formalized as a fixed-point problem in terms of arc flow and transit
frequency temporal profiles. The main innovation is to represent transit supply using a
frequency approach, instead of a run approach, thus not requiring a diachronic graph. By so
doing, intra and inter modal congestion effects can be easily reproduced. For this purpose, a
new dynamic transit line performance model is introduced
Network pricing optimization in multi-user and multimodal context with elastic demand
No full textNetwork Pricing Optimization (NPO) is formulated first as a Network Design Problem (NDP) where the design variables are tolls, the objective function is the Social Surplus and the equilibrium constraint is any current multi-user multimodal stochastic traffic assignment model with elastic demand up to trip generation and asymmetric arc cost function Jacobian. NPO is then formulated also as an Efficient Allocation Problem (EAP), where an optimal flow pattern, the System Optimum (SO), is sought and tolls are consistently determined. Necessary and sufficient conditions for the solutions to both problems are stated, showing the validity of the marginal pricing principle in the context considered. (C) 2002 Elsevier Science Ltd. All rights reserved
Macroscopic arc performance models with capacity constraints for within-day dynamic traffic assignment
No full textIn this paper, we present a new nonstationary link-based macroscopic arc performance model with capacity constraints, derived from an approximate solution to the simplified kinematic wave theory which based on the assumption, often introduced in the algorithms solving Dynamic Traffic Assignment, that the arc inflows are piecewise constant in time. Although the model does not require to introduce any spatial discretization, it is capable of taking implicitly into account the variability of the flow state along the arc accordingly to any concave fundamental diagram. To appreciate the effect of the approximation introduced, the model has been compared in terms of efficiency and effectiveness with three typical existing models, which have been to this end suitably modified and enhanced
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