A two-dimensional framework for the understanding of transportation planning models

This article puts forward the view that, for each transportation planning or management problem, there is a particular way to simultaneously define the multiple levels of procedures useful for the problem and set it in its proper perspective, the latter essentially by the identification of what is exogenous and endogenous to the problem at hand. The joint determination of these levels and of the exogenous/endogenous mix defines the two-dimensional frame of each problem. To develop our view, we extend our previous conceptual framework to include, in the first dimension, an activity location procedure, and to distinguish, in the second dimension, between operational, tactical, and strategic perspectives. We conclude by relativising the use of solution techniques by making them ancillary to the situation planning requirements.     

Working from 9 to 6? An analysis of in-home and out-of-home working schedules

The widespread adoption of information and communication technologies (ICT) and flexible work arrangements have enabled people to schedule their work activities in more flexible ways. New forms of working have already emerged. However, research about flexible work schedules is still scarce. The aim of this study is to determine the factors impacting the propensity to adopt a flexible work schedule, and establish how and to what extent the timing of work is influenced by ICTs, work, and sociodemographic characteristics. The analysis suggests that work-related characteristics and ICT usage seem to be more important for work-schedule flexibility than sociodemographic characteristics are.     

Behavior-consistent real-time traffic routing under information provision

The problem addressed here involves a controller seeking to enhance traffic network performance via real-time routing information provision to drivers while explicitly accounting for drivers’ likely reactions towards the information. A fuzzy control modeling approach is used to determine the associated behavior-consistent information-based network control strategies. Experiments are performed to compare the effectiveness of the behavior-consistent approach with traditional dynamic traffic assignment based approaches for deployment. The results show the importance of incorporating driver behavior realistically in the determination of the information strategies. Significant differences in terms of system travel time savings and compliance to the information strategies can be obtained when the behavior-consistent approach is compared to the traditional approaches. The behavior-consistent approach can provide more robust performance compared to the standard user or system optimal information strategies. Subject to a meaningful estimation of driver behavior, it can ensure system performance improvement. By contrast, approaches that do not seek to simultaneously achieve the objectives of the drivers and the controller can potentially deteriorate system performance because the controller may over-recommend or under-recommend some routes, or recommend routes that are not considered by the drivers.     

Adjusting the service? Understanding the factors affecting bus ridership over time at the route level in Montréal,Canada

Transportation - Like many cities across North America, Montréal has experienced shrinking bus ridership over recent years. Most literature has focused on the broader causes for ridership...     

How optimal was the Sydney Metro contract?: Comparison with international best practice

The New South Wales (NSW) government created the Sydney Metro Authority to design, build and operate a completely separate underground Metro rail system to supplement the existing public transport network in Sydney. By the time the NSW government abruptly cancelled the entire Metro project in early 2010, the Authority had conceived and designed a contract that was proceeding to procurement. This paper compares the elements of the proposed Sydney Metro contract to findings of the literature on optimal contracting and optimal incentives and on PPP best practice. The paper concludes that the Metro seems to have at least implicitly drawn fairly heavily on best practices and principles, but that its ultimate failure to be implemented is an instructive lesson about how operating environment can impede integration of useful knowledge and experience.     

DRAG-ALZ-1, a first model of monthly total road demand,accident frequency,severity and victims by category,and of mean speed on highways,Algeria 1970–2007

We construct a first country-wide model of demand for road use and of road safety outcomes for Algeria making use of the DRAG-type framework and of flexible regression estimation methods that make a demonstrable difference to the quality of our results. We imply that the availability of high quality Algerian data could make it worthwhile not only to consider updates of the model with longer data series but also to study variants of the model, notably with disaggregation of freight activities across industrial sectors.     

Coupled renewal model of ocean viscous sublayer, thermal skin effect and interfacial gas transfer velocity

A previously developed renewal model included parameterizations for the thermal skin effect and interfacial gas transfer velocity. The more readily available cool skin data were used for an adjustment of the gas transfer parameterization. In this work, the renewal concept is extended to include the velocity difference across the viscous sublayer and to account for the stage of surface wave development. As a result, the empirical coefficients that enter the renewal model have been specified more accurately using laboratory data on the surface wind drift current. In addition, the coefficient linking the cool skin and gas transfer parameterization formulas has been determined from the probability distribution function for renewal events. A comparison of the upgraded renewal model with the thermal skin data collected during the COARE and more recent field programs and with gas transfer data collected during GasEx-01 experiment suggests that the renewal model can be a useful tool for producing a physically based parameterization for the interfacial CO₂ transfer velocity. Model uncertainties associated with the effect of surface films are discussed.     

Modelling the Contact Between Wheel and Rail Within Multibody System Simulation

In modern railway industry the simulation of the behaviour of railway vehicles has become an important design method during the last years. Modern simulation packages offer modelling elements that are highly adapted for standard and unusual simulation scenarios. A specific application case is the simulation of a railway vehicle travelling through a switch. It makes high demands on the simulation software due to the inconvenient modelling elements needed: the changing rail profiles on the blade rail and in the crossing vee area as well as the guard rail with its additional contact at the back of the wheel. The article gives an overview over the state of the art in railway vehicle simulation and presents a simulation of a passenger car running through a switch as an application example.     

TARGETED ACTIVATION OF CD_（8）~（＋） CELLS AND INFECTION OF β_2－MICROGLOBULIN－DEFICIENT MICE FAIL TO CONFIRM A PRIMARY PROTECTIVE

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Analysis and optimisation of objective vehicle dynamics testing in winter conditions

Objective testing of vehicle handling in winter conditions has not been implemented yet because of its low repeatability and its low signal-to-noise ratio. Enabling this testing, by identifying robust manoeuvres and metrics, was the aim of this study. This has been achieved by using both experimental data, gathered with steering-robot tests on ice, and simulation models of different complexities. Simple bicycle models with brush and MF-tyre models were built, both optimally parameterised against the experimental data. The brush model presented a better balance in complexity performance. This model was also implemented in a Kalman filter to reduce measurement noise; however, a simpler low-pass filter showed almost similar results at lower cost. A more advanced full vehicle model was built in VI-CarRealTime, based on kinematics and compliance data, damper measurements, and real tyre measurements in winter conditions. This model offered better results and was therefore chosen to optimise the initial manoeuvres through test design and simulations. A sensitivity analysis (ANOVA) of the experimental data allowed one to classify the robustness of the metrics. Finally, to validate the results, the proposed and the initial manoeuvres were tested back to back in a new winter campaign.