A microeconomic interpretation for the system optimal traffic assignment problem with nonadditive path cost

Using a Bergson–Samuelson welfare function, we outline a microeconomic interpretation of the effects of the non-linearity in the time/cost relationship for travellers in a congested transport network. It is demonstrated that a marginal cost traffic flow assignment following Wardrop's second principle, although it minimizes the total cost of a transport network, may reduce social welfare compared to the market equilibrium assignment based on Wardrop's first principle. A welfare-maximizing assignment model is presented and used to show that if the travellers' utility functions are linear, the assignment that maximizes social welfare will be the same as the assignment that minimizes total network cost, but if users' utility functions are non-linear (reflecting the traditional non-satiation and diminishing marginal utility axioms), the two assignments will be different. It is further shown that the effects of this non-linearity are such that a welfare-maximizing assignment will meet with less user resistance than a minimum total network cost assignment.     

Outsourcing rural school transportation: A Brazilian handbook for practice at the municipal level

In Brazil, Rural School Transportation (RST) falls under the responsibility of state and municipal governments. However, there are no clear rules to guide the provision of this essential service. RST in Brazil is characterised by inefficient contracting practices, poor service control by school administration, and lack of legal instruments to penalise poor services, thus allowing operators to run services according to their own commercial criteria. In addition, payment is low, leading to the employment of old vehicles, lack of safety equipment, and non-convenient routes, among other aspects. As a result, school children provided with this service are subject to long travel time over large distances, and irregular and late services, coupled with poorly maintained roads. When children finally arrive at school they are tired, which often negatively affects their school performance and attendance, contributing to early school drop-out. In order to contribute to the improvement of school transportation quality, state and municipal authorities must develop the required organisational, planning, and regulatory skills. Accordingly, this article addresses the elements and the structure of a handbook that is being elaborated for local governments.     

Modelling passengers,buses and stops in traffic microsimulation: review and extensions

In the last decade, significant research efforts and technology have been dedicated to the development of microsimulation tools for a better representation of traffic systems. As a result, several commercial packages appeared and they are used nowadays in the detailed modelling of different transportation systems and operations for specific project evaluations and local designs, mostly within the urban context. After reviewing the specialized literature, we realized that most of these microsimulation tools are oriented to the movement of cars, leaving the public transportation systems as a complement, just for a realistic representation of the transportation system as a whole, but always oriented to simulate cars. In this paper, the objective is to provide guidelines on how to incorporate the necessary entities and components for a proper simulation of public transport systems in a microsimulation environment. Thus, the different approaches to simulate transit systems at a microlevel are discussed, highlighting the necessity of including stops, passengers and transit vehicles explicitly as entities within the microsimulation environment, for modelling transfer operations, control strategies, etc. Several examples are then provided to quantify the impact of such representations, for different cases and potential simulation platforms. Copyright © 2010 John Wiley & Sons, Ltd.