A fractional perspective to the modelling of Lisbon’s public transportation network

Transportation - Urban growth originates multiscale spatial patterns, such as those of transportation networks. Here, the public transportation network (PTN) of the city of Lisbon is analysed from...     

Alternative financing for Bus Rapid Transit (BRT): The case of Porto Alegre, Brazil

In the 1970s, Brazil was leading the implementation of high-flow bus priority schemes, but now cities are less capable of financing public infrastructures. This paper explores the private sector participation in the provision of transit infrastructure based on Public-Private Partnerships (PPP) for Bus Rapid Transit (BRT). The Porto Alegre BRT contemplates interchange terminals planned to accommodate retail and service activities. It is expected that these areas shall generate enough revenues to remunerate private investors, under a PPP scheme, for the construction of terminals and part of the infrastructure required to upgrade some sections of the existing busways to BRT standards.     

Part II: Policy instruments for sustainable road transport

Without questioning the fact that to achieve efficiency emitters should pay for the true costs of their actions (a core principle of economic policies such as pollution taxes), we find sufficient evidence in the literature to demonstrate that many other policy instruments can be used in combination with taxes and permits to ensure that the transport needs of the present generation can be met without compromising the ability of future generations to meet any needs of their own.The policies and policy aspects considered in this paper broadly fall into three categories: physical policies, soft policies, and knowledge policies. All three aim to bring about changes in consumers’ and firms’ behaviour, but in different ways. The first category includes policies with a physical infrastructure element: public transport, land use, walking and cycling, road construction, and freight transport. We also consider the particular challenges for mobility in developing countries, and how these may be addressed. Soft policies, on the other hand, are non-tangible aiming to bring about behavioural change by informing actors about the consequences of their transport choices, and potentially persuading them to change their behaviour. These measures include car sharing and car pooling, teleworking and teleshopping, eco-driving, as well as general information and advertising campaigns. Finally, knowledge policies emphasise the important role of investment in research and development for a sustainable model of mobility for the future.The main findings can be summarised as follows.

Physical policies

An increase in the use of public transport, combined with a decrease in the use of private cars, can reduce traffic congestion and, more importantly, carbon dioxide (CO₂) emissions, as public transport generally causes lower CO₂ emissions per passenger kilometre than private cars. Public transport fares are subsidised in most places, which can be justified by economies of scale and by the fact that public transport can reduce total road transport externalities. London, Singapore, Portland and Curitiba are all examples of good practice at government level, having achieved reliable, frequent and integrated public transport.Policies to increase public transport use must be part of an integrated policy. Integrated policy refers to integration across different modes of transport, different government objectives (such as the economy, health and the environment), considering the needs of different social groups, and coordinating action between the relevant government institutions. There is evidence that a lack of coordination can jeopardise the achievement of policy objectives.A sustainable model for transport policy also requires integration with land-use policies. These may be somewhat limited within the bounds of existing cities, but as cities grow and new cities are built, urban planners must put more emphasis on land use for sustainable transport in order to reduce congestion and CO₂ emissions. Sustainable land-use policy can direct urban development towards a form that allows public transport as well as walking and cycling to be at the core of urban mobility.Walking and cycling, which improve general health and produce no tailpipe emissions, constitute an excellent alternative to motorised transport on short-distance trips within towns and cities. The policies which can incentivise walking and cycling include crime reduction to make streets safer, well-maintained and clean pavements, attractive street furniture, safe crossings with shorter waiting times, dedicated cycle paths, showers in offices, and lower speed limits, to name but a few.Road construction and expansion used to be seen as one of the most promising ways to reduce traffic congestion. However, in the mid-1990s, the issue was reassessed and it was found that building and expanding roads, increased, rather than decreased, congestion, and ultimately induced higher levels of travel demand. The reason for this is that the extra capacity reduces the general cost of travelling and the less expensive the travel, the more it will be demanded. Regarding freight modal shift, road transport is much more polluting than rail per tonne-km of goods transported and therefore a shift towards greater use of rail in freight transport is desirable. Inadequate infrastructure is the main obstacle preventing this modal shift taking place.Developing countries face great mobility challenges: rural areas are often extremely poorly connected to transport infrastructure, such that, in contrast to the situation in developed countries, the benefits of road construction can strongly outweigh the total costs (including environmental ones). The main challenge, however, is to develop a solution to the problems arising from the combination of urbanisation and motorisation. Integration of transport and land-use policy will be key to rising to this challenge.

Soft policies

Car sharing and car clubs can also potentially reduce CO₂ emissions, although the aggregate reduction in congestion and emissions has not been measured with an adequate degree of precision in the literature. Teleworking and teleshopping can potentially reduce congestion and also CO₂ emissions. However, the evidence for this reduction is rather mixed, as it is unclear whether these measures lead to overall reductions in road transport.Eco-driving campaigns aim to inform and educate drivers in order to induce them to drive in a fuel-efficient and thus environmentally friendly way. There seems to be some consensus in the literature that eco-driving could lead to reductions in CO₂ emissions of around 10 per cent.Information and education policies have often been advocated as instruments which may affect behavioural change. We find in this paper that these types of measures are necessary, but not sufficient for behavioural change. Advertising and marketing may go a long way in changing peoples’ behaviour. In California, for example, Kahn (2007) finds the “Prius” effect: the Toyota Prius is preferred by consumers relative to other similarly green vehicles, probably due to extensive marketing and celebrity endorsements. Family life changes are also found to trigger changes in behaviour ( [Goodwin, 1989] and [106]). People whose lives are being changed by some important development (birth of a child, retirement, etc) tend to respond more to changes in the relative attractiveness of different transport modes. Advertising campaigns promoting a modal shift towards public transport, for instance, may thus be more successful if targeted at people in the process of important life transitions.

Knowledge policies

Research and Development is crucial for developing sustainable and low-carbon transport for the future, and it is essential that governments provide incentives to undertake R&D, so that new low-carbon technologies in the transport sector can be demonstrated and applied at a large scale.Finally, we consider the issue of policy combination and integration. There is evidence that the combination and integration of policies can lead to positive side-effects and synergies. Policy integration is crucial in order to rise to the challenges we face in moving towards a sustainable mobility model. We conclude that classical economic policies may be successfully combined with a number of policy measures discussed in this paper in order to achieve sustainability in transport.     

Assessment of port economic impacts on regional economy with a case study on the Port of Lisbon

This article presents a method of assessing the economic impacts of ports at both regional level and national level, through application of input–output analysis. To this end, a methodology for data collection is proposed, which combines a top-down with a bottom-up approach which should help in surpassing some of the difficulties commonly faced in port economic impact studies. The presented methodology allows port planners and policymakers to assess the economic significance and geographic reach of port investments. This study considers the economic impacts of the port cluster and the socio-economic significance of port user industries. The several layers of the analysis are kept separate to allow a better grasp of direct and indirect impacts. The proposed methodology is demonstrated in a study of the Port of Lisbon, which confirms the significance of this port to the Portuguese economy, and also demonstrates that the influence of the Port of Lisbon is mostly limited to an area in close proximity to the port. Therefore, results suggest that investments for the development of logistic infrastructures associated with the port should concentrate in the immediate hinterland of the port.     

Geometric modelling of bulbous bows with the use of non-uniform rational B-spline surfaces

Nowadays, bulbous bow forms have become a common design feature in most conventional ship designs. The design of a bulbous bow is usually attempted with the use of certain form parameters that are imposed using the designer's experience or regression values that provide the optimum parameters based on experimental tests or computational fluid dynamics (CFD) calculations. In this article, the geometric modelling of a bulbous bow form that complies with a series of parameters is presented. First, a wire model was constructed with cubic B-spline curves that hold certain form parameters that the designer wants to impose. Second, a B-spline surface that fits these splines was mathematically constructed. A review of the influence of the design parameters used on the bulbous bow properties was made. This method could be used prior to numerical optimization of a bulbous bow because different variations of the design can be easily generated. These variations can be tested numerically using CFD software. A practical application example of the method is shown.     

A study of the response of chlorophyll-a biomass to a winter upwelling event off Western Iberia using SeaWiFS and in situ data

Observations of a winter upwelling event off Western Iberia shelf/slope in the area of influence of the Western Iberia Buoyant Plume (WIBP) were conducted in February 2000. Spatial patterns and time evolution of the chlorophyll-a (chl-a) biomass are analysed, based on in situ and satellite data. SeaWiFS-derived chl-a concentration L2 products were used to track the chlorophyll front and estimate its westward migration velocity (maximum up to 29 km day⁻¹), as well as to characterize the frontal system and its evolution. A method associating the type of spectral signature of a pixel to the fraction of chlorophyll probed by SeaWiFS enabled the estimation of the chl-a biomass within error intervals. High chlorophyll concentrations (for wintertime) were observed over the shelf and slope, up to large distances to the coast. Due to the WIBP, a shallow Ekman layer developed, being nearly coincident with the stratified upper meters. The transport comprised westward advection and stretching of the plume, with little entrainment with the offshore deep mixed layer waters. The relative enlargement of the total area of the Inside-Front Zone (IFZ) during the upwelling event was roughly accompanied by the maintenance of the average biomass per unit of area, considering the water column up to depths of interest. This suggests that there was a net increase of chl-a biomass inside the water column associated with the IFZ, roughly proportional to the increase in the IFZ area. Retention of phytoplankton in the shallow stratified nutrient-rich waters of the WIBP was a key factor for this increase in chl-a biomass.     

Wanting to travel,more or less: Exploring the determinants of the deficit and surfeit of personal travel

This study investigates the determinants of peoples desire to increase or decrease the amount of travel they do. We use data from 1,357 working commuters, residents of three different neighborhoods in the San Francisco Bay Area, California. The dependent variables are indicators of Relative Desired Mobility for ten categories of travel (short- and long-distance overall and by several mode- and purpose-specific categories). These variables are measured on a five-point ordinal scale ranging from much less to much more, through which the respondents indicated the amount of travel they want to do (in the category in question) compared to what they are doing now. Censored ordered probit models were developed for these variables, with explanatory variables including general travel attitudes, specific liking for travel in each of the same separate categories, objective and subjective measures of the amount currently traveled in each category, and personality, lifestyle, and socio-demographic characteristics. The results support the hypotheses that the liking for travel has a strong positive impact, and subjective qualitative assessments of mobility have a strong negative impact, on the desire to increase ones travel. Finally, a number of general types of effects on Relative Desired Mobility were identified, among them complementarity and substitution effects. The results of this study can provide policy makers and researchers with new and valuable insight into key principles that affect individual travel demand.     

Telemetric system for monitoring and automation of railroad networks

This paper describes a new method of real-time train monitoring based on the ZigBee/IEEE 802.15.4 protocol. The system consists of a mobile device embedded in the moving train which transmits parameter signals that are being measured by a base unit with the help of routers. When applied, the technique monitors and controls vehicles operating on permanent routes, making a real-time evaluation of their performance and location, and allowing an effective planning of trains. It consists of a low cost, low power consumption and safe modular technology capable of monitoring many different variables simultaneously.     

Increase of metro line capacity by optimisation of track circuit length and location: In a distance to go system

The signalling system affects the type of service that can be provided on any particular railway line. The aims set when it comes to designing these systems to operate a railway line are: to ensure safety of operation and to ensure flexible and efficient running. When building a line capacity optimisation algorithm, it must reach a compromise solution between two parameters: minimise the interval between trains and keep journey time as low as possible. This paper aims to describe the algorithm developed between METRO DE MADRID and CITEF (Railway Technology Research Centre of the Universidad Politécnica de Madrid – UPM) that allows the capacity of an underground line equipped with ATP Distance To Go systems to be studied and optimised. This algorithm facilitates the tasks of signalling design and optimisation. Copyright © 2010 John Wiley & Sons, Ltd.