Logística de la distribució urbana de mercaderies

La Distribució Urbana de mercaderies és un procés vital i per tant estratègic per al creixement econòmic, social i cultural d'una ciutat. Múltiples factors i actors diversos presenten interessos contraposats que xoquen amb especial virulència a les ciutats europees més dinàmiques i al centres històrics de qualsevol ciutat. No existeixen solucions simples a aquest problema, i el sector s'atorga històricament un paper de "víctima" d'un cert "oblit" a tots els nivells. L'article revisa la situació i els actors implicats i els seus punts de vista, analitza els costums actuals, exposa les tendències detectades i proposa millores d'implantació factible.La Distribución Urbana de mercancías es un proceso vital, y por tanto estratégico, para el crecimiento económico, social y cultural de una ciudad. Múltiples factores y actores diversos presentan intereses contrapuestos que chocan con especial virulencia en las ciudades europeas más dinámicas y en los centros históricos de cualquier ciudad. No existen soluciones simples a este problema, y el sector se otorga históricamente un papel de "víctima" de un cierto "olvido" en todos los niveles. El artículo revisa la situación y los actores implicados y sus puntos de vista, analiza las costumbres actuales, expone las tendencias detectadas y propone mejoras de implantación factible.The Urban Goods Distribution is a vital and therefore strategic process for the economic, social and cultural growth of a city. Many factors and actors have opposite interests, that clash with special virulence in the most dynamic European cities, and in the historic centres of any city. There are not easy solutions to this problem, and this sector gives itself a role of "victim" of "forgetfulness" at all levels. The article revises the involved actors and their points of view, analyses the current habits, shows the detected trends, and proposes feasible measures for improvement.La distribution urbaine des marchandises est un processus vital et, par conséquent, stratégique pour le développement économique, social et culturel d'une ville. De nombreux facteurs et divers acteurs présentent des intérêts opposés qui choquent avec une force spéciale dans les villes européennes les plus dynamiques et dans les centres historiques des villes. Les solutions faciles n'existent pas et le secteur s'attribue historiquement un rôle de «victime» d'un certain «oubli» à tous les niveaux. L'article examine la situation et les acteurs impliqués ainsi que leur point de vue, analyse aussi les coutumes actuelles, expose les tendances détectées et propose des améliorations d'implantations possibles

Implementation of connected and autonomous vehicles in cities could have neutral effects on the total travel time costs: modeling and analysis for a circular city

Autonomous vehicles promise to revolutionize the automobile market, although their implementation could take several decades in which both types of cars will coexist on the streets. We formulate a model for a circular city based on continuous approximations, considering demand surfaces over the city. Numerical results from our model predict direct and indirect effects of connected and autonomous vehicles. Direct effects will be positive for our cities: (a) less street supply is needed to accommodate the traffic; (b) congestion levels decrease: travel costs may decrease by 30%. Some indirect effects will counterbalance these positive effects: (c) a decrease of 20% in the value of travel time can reduce the total cost by a third; (d) induced demand could be as high as 50%, bringing equivalent total costs in the future scenario; (e) the vehicle-kilometers traveled could also affect the future scenario; and (f) increases in city size and urban sprawl. As a conclusion, the implementation of autonomous vehicles could be neutral for the cities regarding travel time costs. City planning agencies still have to promote complementary modes such as active mobility (walking and bicycle), transit (public transportation), and shared mobility (shared autonomous vehicles and mobility as a service).Peer ReviewedPostprint (published version

Expectatives de l'evolució del transport de mercaderies i persones a l'arc mediterrani

El Departament de Territori i Sostenibilitat organitza un cicle de tres jornades de treball i de reflexió amb l’objectiu principal d’identificar i analitzar quines són les condicions territorials que afavoreixen l’activitat econòmica internacional de Catalunya.Postprint (published version

Traffic accident severity analysis in Barcelona using a binary probit and CHAID tree

Traffic accidents are still wide causation for fatalities around the globe. The set of alarm for this cause of deaths is still on, since the number of fatalities is still representing an enormous issue and a challenge for most governments. In Barcelona, similar to the rest of the world, traffic accidents are threatening lives and raising the need to lessen the number of both fatalities and severities. This study is conducted to grasp the correlations between different classification factors with accident severities and fatalities. A total of 47,153 traffic accident cases that occurred between 2016 and 2019 are utilized. Then, a binary probit model and Chi-square automatic interaction detector are exploited to grasp the impact of several risk factors. The results confirmed that males and 65 years and older injured persons are more exposed to severe or fatal injuries compared to other categories. Pedestrians and drivers are found to have higher probabilities compared to passengers in being involved in severe or fatal injuries. Weekends, afternoon, night timings all have higher odds of having severe or fatal traffic accidents. The findings of this study can help road authorities in targeting these risk factors to mitigate their impact to achieve Vision Zero.Peer ReviewedPostprint (author's final draft

From urban congestion pricing to tradable mobility credits: a review

Congestion is still a big challenge for urban mobility while vehicle sharing, eCommerce and autonomous vehicles will likely increase the unit veh-km of each vehicle and the density of vehicles moving on the streets. Urban vehicle congestion pricing schemes have been taken as effective solutions to this problem. This paper first reviews the research and application cases of urban congestion pricing through recent years, although with the well-developed theoretical basis and successful practices in Singapore, London, Stockholm, Milan, etc., public acceptance and equity concerns are still the main issues for such policies’ implementation. To circumvent the shortcomings of congestion pricing, a scheme of tradable mobility credits is proposed as an alternative. As travellers are distributed mobility credits within a specific urban area, which are allowed to be traded, those with low vehicle-using demands can sell their credits to those with more demands. Therefore with this scheme, people have the initiative to reduce the use of vehicles. This paper reviews the studies on this new urban mobility management strategy and compared it with ordinary congestion pricing schemes. Finally, we conclude the gap and possible directions for future works.Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats SosteniblesObjectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles::11.2 - Per a 2030, proporcionar accés a sistemes de transport segurs, assequibles, accessi­bles i sostenibles per a totes les persones, i millorar la seguretat viària, en particular mitjan­çant l’ampliació del transport públic, amb especial atenció a les necessitats de les persones en situació vulnerable, dones, nenes, nens, persones amb discapacitat i persones gransPostprint (published version

Working hours and traffic accident injuries: case study in Barcelona

Working hours in Spain is generally last for 8 hours per day with a maximum of 40 hours per week. Working hours, therefore, can impact the traffic flow and characteristics due to the intensity of road usage by different road users. On the other side, traffic accidents can also be impacted by several temporal factors that may lead to a higher number of traffic accidents or may increase the level of injury alongside other risk factors. In this study, these timings are examined to comprehend the influence of the temporal factors represented by the working hours scheme on traffic accident injuries in Barcelona. Another temporal factor which is the season of the year is included to provide a wider and clearer image for the conducted results and the current situation. The data is collected from the open data service provided by the City Hall of Barcelona. Data preparation and segregation to include the categories of working hours that may lead to a different level of injury resulted from a traffic accident is, firstly, carried. Then, a machine learning model is applied to classify the correlations for both the temporal factors and traffic accidents. Eventually, a Tree Augmented Naïve Bayes model is applied. The results showed that both working hours timing and summer season have higher probabilities of having traffic accidents slight injuries with different medical care assistance provided compared to other timings.Postprint (published version

Traffic crash injuries occurrence varieties across Barcelona districts

Barcelona (Spain) had a total population of 1,636,762 in 2019 that are distributed on 10 districts across the city. These districts have different characteristics in size and population density. As a result, this can lead to different traffic crashes injuries occurrences and numbers in these areas. Therefore, this study is attempting to determine the conditional probabilities for each district in order to identify the district that has highest number of injuries compared to other areas. A Bayesian network approach is utilized to analyze the dataset and identify the high-risk district alongside analyzing the varieties of traffic crashes during four-year intervals. The results have shown that the district that has the highest population, highest usage of private transport mode, and highest density of passenger cars per km2 (compared to all other districts), has the highest risk of having all types of injuries resulting from traffic crashes. For the temporal factor represented by the four years interval, traffic crashes occurrences varied from district to district based on the level of injury.Postprint (published version

Exploring paradigm shift impacts in urban mobility: autonomous vehicles and smart cities

Urban mobility is a dynamic system that has had a (slow) natural evolution. Scientists and engineers are currently developing new mobility technologies. A progressive paradigm shift will change everything from the fuel type to the way of driving vehicles. Vehicles will progressively become autonomous and will communicate and cooperate with each other. In the long run, profound changes are expected in mobility as a service. Furthermore, urban areas will have a higher level of development, and cities will likely turn into Smart Cities in which the vehicles will interact with the urban infrastructure. The main objective of this paper is to explore the macroscopic effects of mobility interaction in a radial-circular urban road system for current and future cities (Smart Cities). In the literature, there is documentation of the direct effects of autonomous vehicles, but some indirect effects will cause undesirable impacts such as an increase in demand and more congestion, which change the demand behavior and the urban structure. Finally, this paper exhibits the results of direct and indirect effects calculated through analytical tools (Continuous Approximation Method). In fact, our research shows that if demand increases by about 50%, the current scenario could have the same total cost as the future scenario with autonomous vehicles. Moreover, if the city radius increases by about 33% and the subjective value of time decreases about 20%, the benefits of the autonomous cars will be compensated. Therefore, the paper proves that autonomous vehicles could encourage the urban sprawl in the long run. Finally, Administrations should define transport strategies and policies to control these externalities, because autonomous driving could deteriorate mobility even worse than it is now.Peer ReviewedPostprint (published version

Travel time estimation using toll collection data

Transportation System Management (TSM) permits optimizing the current available road network. Travel time and its reliability are key factors in road management systems, as they are good indicators of the level of service in any road link, and perhaps the most important parameter for measuring congestion. This paper presents a new approach for direct travel time measurement using existing toll infrastructure. An efficient and simple algorithm has been developed and implemented in the toll highways in Catalonia, around Barcelona, Spain.Peer Reviewe

Routing design for less-than-truckload motor carriers using ant colony techniques

One of the most important challenges for Less-Than-Truck-Load carriers consists of determining how to consolidate flows of small shipments to minimize costs while maintaining a certain level of service. For any origin-destination pair, there are several strategies to consolidate flows, but the most usual ones are: peddling/collecting routes and shipping through one or more break-bulk terminals. Therefore, the target is determining a route for each origin-destination pair that minimizes the total transportation and handling cost guaranteeing a certain level of service. Exact resolution is not viable for real size problems due to the excessive computational time required. This research studies different aspects of the problem and provides a metaheuristic algorithm (based on Ant Colonies Optimization techniques) capable of solving real problems in a reasonable computational time. The viability of the approach has been proved by means of the application of the algorithm to a real Spanish case, obtaining encouraging results