Vol 13 No 3 (2013)
Vol 13 No 3 (2013)
Articles
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Most project impacts on environment, climate, and health are not valued in markets or in choice situations similar to market transactions. Analysts have to go beyond revealed preferences to stated preference interviews and even to deliberative processes in order to elicit preferences from which the trade-off values (‘prices’) of the expanded cost-benefit analysis (CBA) can be deduced. The comprehensiveness dilemma of social CBA arises with the choice between calculation of ‘prices’ from revealed preferences and communicative construction of ‘prices’ on the basis of preferences stated in deliberation. New methods for eliciting preferences, such as deliberative monetary valuation, yield preferences influenced by ethical and political values. The interpretation of the analytic results then becomes problematic. The comprehensiveness dilemma is that planners must choose between a narrow CBA making good economic sense, and a comprehensive CBA with dubious economic content. By aiming for completeness, CBA changes character from being a summation of changes in individual wellbeing to being a mix of this and the summation of monetary expressions of ethical and political viewpoints and attitudes.
Most project impacts on environment, climate, and health are not valued in markets or in choice situations similar to market transactions. Analysts have to go beyond revealed preferences to stated preference interviews and even to deliberative processes in order to elicit preferences from which the trade-off values (‘prices’) of the expanded cost-benefit analysis (CBA) can be deduced. The comprehensiveness dilemma of social CBA arises with the choice between calculation of ‘prices’ from revealed preferences and communicative construction of ‘prices’ on the basis of preferences stated in deliberation. New methods for eliciting preferences, such as deliberative monetary valuation, yield preferences influenced by ethical and political values. The interpretation of the analytic results then becomes problematic. The comprehensiveness dilemma is that planners must choose between a narrow CBA making good economic sense, and a comprehensive CBA with dubious economic content....
Most project impacts on environment, climate, and health are not valued in markets or in choice situations similar to market transactions. Analysts have to go beyond revealed preferences to stated preference interviews and even to deliberative processes in order to elicit preferences from...
Tore Sager -
The transport of dangerous goods by trucks requires special conditions for rest areas. By considering the set of existing service areas, the present work develops a procedure for selecting the subgroup of the most suitable service areas for modification in order to provide a service to dangerous-goods transporters. Under multiple criteria, a new DEA-inspired model is developed that uses the main characteristics of the problem under study with the goal of selecting the best locations. Through the application of this model to Spanish territory with the help of Geographical Information Systems, various solutions are suggested. The final decision on the number of areas to be located depends on corresponding authorities, whose main priority is to satisfy economic criteria.
The transport of dangerous goods by trucks requires special conditions for rest areas. By considering the set of existing service areas, the present work develops a procedure for selecting the subgroup of the most suitable service areas for modification in order to provide a service to dangerous-goods transporters. Under multiple criteria, a new DEA-inspired model is developed that uses the main characteristics of the problem under study with the goal of selecting the best locations. Through the application of this model to Spanish territory with the help of Geographical Information Systems, various solutions are suggested. The final decision on the number of areas to be located depends on corresponding authorities, whose main priority is to satisfy economic criteria.
The transport of dangerous goods by trucks requires special conditions for rest areas. By considering the set of existing service areas, the present work develops a procedure for selecting the subgroup of the most suitable service areas for modification in order to provide a service to...
M.D. Caro-Vela, C. Paralera, I. Contreras -
Efforts have been made in the last few decades to provide new urban transport alternatives. One of these is carsharing, which involves a fleet of vehicles scattered around a city for the use of a group of members. At first, part of the research effort was put into setting up real life experiments with vehicle fleets and observing the performance of major private operators. In the meantime, with the growth of this alternative and the need to better plan its deployment, researchers started to create more advanced methods to study carsharing systems’ planning issues. In this paper, we review those methods, identifying gaps and suggesting how to bridge them in the future. Based on that review we concluded that carsharing demand is difficult to model due to the fact that the availability of vehicles is intrinsically dependent on the number of trips and vice versa. Moreover, despite the existence of carsharing simulation models that offer very detailed mobility representations, no model is able to characterise accurately the supply side, thus hindering the cost-benefit assessment that is fundamental to justify investment in this transport alternative, in particular those that are being endorsed by the European Union. More complex, however, is the operation of the emerging one-way carsharing systems, where a vehicle may be dropped off at any station, which adds uncertainty as to the location where vehicles can be picked up. Several optimisation approaches have been proposed to mitigate this problem but they are always limited in scope and leave other aspects out for model simplification purposes. Some simulation models have also been developed to study the performance of this type of carsharing system, but they have not included ways of balancing the vehicle stocks.
Efforts have been made in the last few decades to provide new urban transport alternatives. One of these is carsharing, which involves a fleet of vehicles scattered around a city for the use of a group of members. At first, part of the research effort was put into setting up real life experiments with vehicle fleets and observing the performance of major private operators. In the meantime, with the growth of this alternative and the need to better plan its deployment, researchers started to create more advanced methods to study carsharing systems’ planning issues. In this paper, we review those methods, identifying gaps and suggesting how to bridge them in the future. Based on that review we concluded that carsharing demand is difficult to model due to the fact that the availability of vehicles is intrinsically dependent on the number of trips and vice versa. Moreover, despite the existence of carsharing simulation models that offer very detailed mobility representations, no...
Efforts have been made in the last few decades to provide new urban transport alternatives. One of these is carsharing, which involves a fleet of vehicles scattered around a city for the use of a group of members. At first, part of the research effort was put into setting up real life...
Diana Jorge, Gonçalo Correia -
Bicycle-motor vehicle crashes are concentrated along distributor roads where cyclists are exposed to greater volumes of high-speed motorists than they would experience on access roads. This study examined the road safety impact of network-level separation of vehicular and cycle traffic in Dutch urban networks, a strategy for which the term ‘unbundling’ is used. Unbundling vehicular traffic and cycle traffic in an urban network is operationalized as the degree to which cyclists use access roads and grade-separated intersections to cross distributors. The effect on the share of cycling in the modal split is also assessed as unbundling may affect the competitiveness of cycling compared to driving in terms of trip length. The analyses were conducted on Dutch municipalities with more than 50,000 inhabitants. Negative binomial regression was used to analyse the effect on the number of police-reported cyclist deaths and in-patients in bicycle-motor vehicle crashes. A mediation model was tested, with Structural Equation Modelling hypothesizing that unbundling corresponds positively with the cycling modal share via the length of car trips divided by those by bicycle. The results of this study suggest that unbundling improves cycling safety, and increases the share of cycling in the modal split. We recommend unbundling vehicular and bicycle traffic in urban networks, e.g. establishing large traffic-calmed areas with short cuts and standalone paths for cyclists (and pedestrians) and, where feasible, grade-separated intersections such as bicycle tunnels.
Bicycle-motor vehicle crashes are concentrated along distributor roads where cyclists are exposed to greater volumes of high-speed motorists than they would experience on access roads. This study examined the road safety impact of network-level separation of vehicular and cycle traffic in Dutch urban networks, a strategy for which the term ‘unbundling’ is used. Unbundling vehicular traffic and cycle traffic in an urban network is operationalized as the degree to which cyclists use access roads and grade-separated intersections to cross distributors. The effect on the share of cycling in the modal split is also assessed as unbundling may affect the competitiveness of cycling compared to driving in terms of trip length. The analyses were conducted on Dutch municipalities with more than 50,000 inhabitants. Negative binomial regression was used to analyse the effect on the number of police-reported cyclist deaths and in-patients in bicycle-motor vehicle crashes. A mediation model...
Bicycle-motor vehicle crashes are concentrated along distributor roads where cyclists are exposed to greater volumes of high-speed motorists than they would experience on access roads. This study examined the road safety impact of network-level separation of vehicular and cycle traffic in...
Paul Schepers, Eva Heinen, Rob Methorst, Fred Wegman -
Parking policy is still the most directly available instrument for managing traffic demand in many cities. But policy design is subject to difficulties resulting from the complexity of the urban mobility system. This article presents a model framework, based on a system dynamics approach, aimed at assessing the effectiveness of parking policy and quantitatively identifying optimal design at an aggregate spatial level under a level of service maximization objective. An application to a city is developed and the results are discussed in view of their qualitative outcomes and quantitative validity and robustness. It is argued that system dynamics addresses several needs of modellers and decision makers regarding urban parking policy assessment, particularly if parking is used as a traffic management tool. The qualitative results of the model coincide with the prescriptions that would come from the economic theory, even with an objective function based on level of service instead of a broader indicator of efficiency. At the quantitative level, the validation testing of the model application with the available data provided positive indications and no case to reject that a quantitative accurateness useful for policy prescription could be attained provided that some data gaps are fulfilled. The necessary data for calibration seems to be possible to obtain by feasible local empirical observations.
Parking policy is still the most directly available instrument for managing traffic demand in many cities. But policy design is subject to difficulties resulting from the complexity of the urban mobility system. This article presents a model framework, based on a system dynamics approach, aimed at assessing the effectiveness of parking policy and quantitatively identifying optimal design at an aggregate spatial level under a level of service maximization objective. An application to a city is developed and the results are discussed in view of their qualitative outcomes and quantitative validity and robustness. It is argued that system dynamics addresses several needs of modellers and decision makers regarding urban parking policy assessment, particularly if parking is used as a traffic management tool. The qualitative results of the model coincide with the prescriptions that would come from the economic theory, even with an objective function based on level of service instead of...
Parking policy is still the most directly available instrument for managing traffic demand in many cities. But policy design is subject to difficulties resulting from the complexity of the urban mobility system. This article presents a model framework, based on a system dynamics approach,...
João P. R. Bernardino, Maurits van der Hoofd