National and international freight transport models: overview and ideas for further development

This paper contains a review of the literature on freight transport models, focussing on the types of models that have been developed since the nineties for forecasting, policy simulation and project evaluation at the national and international level. Models for production, attraction, distribution, modal split and assignment are discussed in the paper. Furthermore, the paper also includes a number of ideas for future development, especially for the regional and urban components within national freight transport models

A systems dynamics model for the urban travel system

This paper describes the development of a model architecture based on systems dynamics and econometrics. The purpose of the system of models is to simulate the medium­ and long­term effects of urban transport policies with reference to sustainable travel. Three models are presented successively with some results from simulation. The first model relates to the regulation of public transport finance and allows for the constraint of the scarcity of public funds. The second is a modal split model based on price­time modelling. The third is a combined assignment and time of departure choice model based on a queuing representation of congestion. Finally, the coupling between the last two models is described.system dynamics ; Econometrics model ; Urban travel system ; finance ; modal split ; assignment ; time of departure

Transport taxes with multiple trip purposes

I consider an urban transport system in which passenger cars and buses are used for commuting trips and for leisure trips, where both transport modes contribute to congestion, and where commuting is a strict complement to taxable labour supply. The optimal tax structure for raising a given amount of government revenue is discussed for the cases where differentiation of the transport tax between trip purposes is and is not possible. Using a stylised dataset for Belgian urban enviroments, the optimal tax structure is computed. When differentiation of transport taxes between trip purposes is possible, a shift to the taxation of relative complements to leisure is observed. When differentiation is not possible, reforming transport taxes generates substantial welfare gains only when the labour tax can be simultaneously reduced.transport; externalities; congestion taxes; general equilibrium welfare effects

Transport tax reform, commuting and endogenous values of time

Previous studies of transport tax reform have typically assumed that the reform itself does not affect the marginal value of time. In this paper we consider a model of urban transport with two trip purposes, commuting and non-commuting, to analyse the effects of transport tax reform on the value of time and marginal external congestion costs. The theoretical results suggest that the assumption of multiple trip purposes implies that these effects are non-trivial. Consequently, assuming exogenous time values may lead to inaccurate estimates of optimal congestion taxes and of the welfare effects of transport tax reform. Empirical work using Belgian data illustrates the potentially large effect of transport tax reform on time values. In fact, the majority of the tax reform exercises studied reduce traffic levels but raise time values and marginal external congestion costs.tax reform; congestion; value of time

Land-Use Transport Interaction: State of the Art

This paper investigates innovative approaches to the integration of land-use and transport planning in urban regions. Engineering, economic and social-science based theories and empirical studies are analyzed regarding their ability to explain the interaction between land use and transport - that land use determines traffic flows and that transport infrastructure changes land-use patterns. In addition, this paper provides an overview of the state of the art of computer models for the simulation of land use and transport. Based on these theories and models the effectiveness of policies to influence land use and transport in urban regions is assessed.Urban location theory, transportation research, land use- transport interaction, urban simulation modeling, location choice

Parallel implementation of the TRANSIMS micro-simulation

This paper describes the parallel implementation of the TRANSIMS traffic micro-simulation. The parallelization method is domain decomposition, which means that each CPU of the parallel computer is responsible for a different geographical area of the simulated region. We describe how information between domains is exchanged, and how the transportation network graph is partitioned. An adaptive scheme is used to optimize load balancing. We then demonstrate how computing speeds of our parallel micro-simulations can be systematically predicted once the scenario and the computer architecture are known. This makes it possible, for example, to decide if a certain study is feasible with a certain computing budget, and how to invest that budget. The main ingredients of the prediction are knowledge about the parallel implementation of the micro-simulation, knowledge about the characteristics of the partitioning of the transportation network graph, and knowledge about the interaction of these quantities with the computer system. In particular, we investigate the differences between switched and non-switched topologies, and the effects of 10 Mbit, 100 Mbit, and Gbit Ethernet. keywords: Traffic simulation, parallel computing, transportation planning, TRANSIM

Relationship between spatial proximity and travel-to-work distance : the effect of the compact city

In this paper, an assessment is made of the relationship between selected aspects of spatial proximity (density, diversity, minimum commuting distance, jobs-housing balance and job accessibility) and reported commuting distances in Flanders (Belgium). Results show that correlations may depend on the considered trip end. For example, a high residential density, a high degree of spatial diversity and a high level of job accessibility are all associated with a short commute by residents, while a high job density is associated with a long commute by employees. A jobs-housing balance close to one is associated with a short commute, both by residents and by employees. In general, it appears that the alleged sustainability benefits of the compact city model are still valid in a context of continuously expanding commuting trip lengths

Survey of air cargo forecasting techniques

Forecasting techniques currently in use in estimating or predicting the demand for air cargo in various markets are discussed with emphasis on the fundamentals of the different forecasting approaches. References to specific studies are cited when appropriate. The effectiveness of current methods is evaluated and several prospects for future activities or approaches are suggested. Appendices contain summary type analyses of about 50 specific publications on forecasting, and selected bibliographies on air cargo forecasting, air passenger demand forecasting, and general demand and modalsplit modeling

An analysis of short haul air passenger demand, volume 2

Several demand models for short haul air travel are proposed and calibrated on pooled data. The models are designed to predict demand and analyze some of the motivating phenomena behind demand generation. In particular, an attempt is made to include the effects of competing modes and of alternate destinations. The results support three conclusions: (1) the auto mode is the air mode's major competitor; (2) trip time is an overriding factor in intermodal competition, with air fare at its present level appearing unimportant to the typical short haul air traveler; and (3) distance appears to underly several demand generating phenomena, and therefore, must be considered very carefully to any intercity demand model. It may be the cause of the wide range of fare elasticities reported by researchers over the past 15 years. A behavioral demand model is proposed and calibrated. It combines the travel generating effects of income and population, the effects of modal split, the sensitivity of travel to price and time, and the effect of alternative destinations satisfying the trip purpose

Aviation Forecasting in ICAO

Opinions or plans of qualified experts in the field are used for forecasting future requirements for air navigational facilities and services of international civil aviation. ICAO periodically collects information from Stators and operates on anticipated future operations, consolidates this information, and forecasts the future level of activity at different airports