ROUGH DRAFT authorea.com/110608
Main Data History
Export
Show Index Toggle 0 comments
  •  Quick Edit
  • journal: Transportation Research E

    The use of public transportation network for urban intermodal logistics in congested city centers

    The Megacities around the world are facing a rapid growth in their markets. An increasing number of new customers are demanding more services and products in urban areas, which are often very dense and congested. However, the traditional road-based logistics strategies to supply those customers have been inadequate to deal with largely restricted delivery operations. These challenges can come up either due to legislation that restricts the travel of trucks inside the city centers or to the increasing number of medium size vehicles in the streets. This paper shows a method to compare two options to deliver the products in the city centers, one using the traditional road-based delivery, and another with a intermodal rail-road model using the public transit system. A data analysis of the city’s Master Transportation Plan shows a low level of utilization of the public transit system, allowing to study the intermodal freight transportation in that system in urban areas. Henceforth, to cope with transit time and cost, we developed a model assessing the sensitivity and opportunities analyzing the Rio de Janeiro’s case study. There is an evidence that the model is sensible to the proposed congestion factor in the transit time and it can be an approach to improve the level of service of the deliveries inside the city centers, decreasing the needed number of medium size trucks. The results have shown that is possible to use intermodal transportation when the road-based distribution operation suffers from a certain level of congestion in the haulage and in the last-mile stage.

    keywords:
    Intermodal operations, urban logistics, congested areas, Megacity distribution
    journal: Transportation Research E\cortext

    [mycorrespondingauthor]Corresponding author

    url]www.megacitylab.mit.edu

    Highlights

    • 1.

      A new methodology based on public data is provided to analyze the Megacity’s population and stores density.

    • 2.

      An assessment of the public transit system capacity to identify opportunities for freight haulage.

    • 3.

      A time-cost model which incorporates a congestion factor comparing truckload and intermodal operations.

    • 4.

      A citywide analysis of the use regions for different modes of transport.

    journal: Transportation Research E

    Introduction

    Motivation

    The Megacities11Cities with more than 10 million inhabitants. around the world are facing a rapid growth in their markets. The term ‘megacity’ is associated with metropolises with several million inhabitants. There are many challenges in many domains of urban life in megacities, especially those in the developing world. For example, an increasing number of new customers are demanding more services and products in these urban areas, mainly in emerging markets, often very dense and congested. The process to fulfill these needs is denominated ”City Logistics”, and one critical part of it is the urban distribution of products, which is predominantly road-based. It contributes to worsening the traffic while also being affected by it, as a counter-effect, impacting negatively the dimensions of sustainability (environmental and financial) (Rode, 2013).

    At those urban areas, the logistic operations show specific characteristics differing them from the general logistic activities (Barceló et al., 2007).

    Rever essa parte

    As stated by Dablanc (2007), the urban policies regarding freight mobility are inefficient. Also, the city itself is only a space for circulation and unloading and loading of goods. Cities tend to concentrate many negative characteristics of the freight road transport industry. It forces the deliveryman to adjust to the city environment and its many constraints (congestion, narrow streets, physical obstacles of all sorts, etc.). The operators to reduce their cost by increasing the life duration of their vehicles or the working hours they can devote to their job. The sub contractor has to overwork or disregard local regulations in order to remain in business. One would need extremely tight (and strictly enforced) legal access restrictions to oblige a truck driver to reorganize its deliveries. Many cities identify maximum size or weight of trucks authorized to deliver in city centers. They add delivery time windows, they view truck traffic as something they should ban or at least strictly regulate, and few of them consider freight activities as a service. Transport plans must optimize freight urban delivery, harmonize local truck regulations, provide sufficient and adequate delivery on-street bay areas, plan the provision of urban logistic spaces, particularly those related to rail and waterborne transport. Every job generates one delivery (or pick up) per week. Goods movement, which represent between \(20\%\) and \(30\%\) of vehicle kilometer and between \(16\%\) and \(50\%\) of the emission of air pollutants by transport activities in a city, depending on the pollutant considered. Delivery rounds are organized from terminals which are often located at more than 50 or 100 miles form the city center. However, The city of Barcelona has created an innovative organization of some of its main urban areas, by devoting the two lateral lanes to traffic in the peak hours, deliveries during off-peak hours, and residential parking during he night.

    For example, the parking process is restricted by few available areas, as well the time to perform the deliveries is shorter than at the city outskirts, to cite a few restraints. The relevance of urban freight transportation can also be shown by the last-mile distribution cost within the freight transportation chain. About \(40\%\) of the that cost are due to pick-up and delivery operations, which often take place in urban areas, on the total door-to-door cost in combined transport (Taniguchi et al., 2004).

    Nevertheless, the intermodal freight transportation in urban contexts is little explored compared to an interurban or regional, distribution operations. This intermodal network can be characterized by nodes, representing transfer or transshipment points and links, representing the possible routes and flows of goods on a network (Crainic et al., 2007). Hence, the interrelations among possible different uses of several transportation modes to deliver the products to customers are not well analyzed in the urban context.

    Objectives

    Therefore, the general objective of this paper is to provide an innovative framework to analyze the intermodal operations, inside the city centers, in very high-density cities using alternative schemes of distribution. Furthermore, the specific aims of this paper are two fold. First is to analyze the utilization of the public transit system in this context, and identify the opportunities on its actual capacity to carry freight, and second is to establish an intermodal cost and time model to assess the use of intermodal operations in an megacity environment, subject to congestion patterns in the stem haul and last-mile section of the delivery process. Both objectives are based on the data available of the public transit systems of a megacity and its demographics patterns, in this case, the city of Rio de Janeiro. The potential contribution is thus to provide an analytical framework to study the insertion of freight on existing public transit systems, which have capacity in off-peak periods to carry goods to the congested city center.

    Rascunho

    O transporte rodoviário tem sido o líder de mercado por um longo tempo e, portanto, tem afetado os padrões logísticos. Para o transporte ferroviário de recuperar a quota de mercado no transporte urbano terá de alcançar este objectivo. operações de transporte rodoviário têm comparativamente baixo custos de infra-estrutura e comumente não incorporar os seus custos externos (Robinson et al., 2004).

    Também é necessária a melhoria na razão custo-qualidade do transporte intermodal, devido a fatores como a falta de confiabilidade, longos tempos de espera, as baixas frequências e slots limitados no calendário (Trip et al., 2002). Além disso, há também fatores em favor do transporte ferroviário urbano intermodal de mercadorias, por exemplo, o congestionamento na rede rodoviária e o fato de que em muitos casos os fluxos urbano de mercadorias exige um ponto de transbordo rodoviário unimodal devido a restrições de logística da cidade, por exemplo restrições operacionais relativas as dimensões dos veículos rodoviários ou sobre o procedimento de carregamento e descarga.

    Além disso, a necessidade de se reduzir gases de efeito estufa (GEE) é evidente e há uma demanda para o desenvolvimento de sistemas de transporte mais sustentáveis. Quando a sustentabilidade é um dos objetivos do transporte intermodal, o princípio deveria ser que o frete deve ser transportado na medida do possível com o transporte ferroviário e, em seguida, distribuídos por estrada, com distâncias tão curtas quanto possível (UN, 2001).

    O transporte ferroviário intermodal sofre de uma série de problemas que restringem a sua competitividade em curtas distâncias. Vários pesquisadores da área têm feito contribuições em encontrar a distância mínima que o transporte ferroviário intermodal pode competir com serviços rodoviários. Os resultados europeus encontram-se na faixa de 400-600 km (van Klink et al., 1998). O transporte intermodal deve ser capaz de atender mais fluxos de transporte, e pequenos fluxos em distâncias relativamente curtas, que podem ser alcançados através da implementação de frequências de transporte mais elevados e servindo mais destinos. Um trem da linha intermodal fazendo paradas intermédias ao longo do seu percurso é uma solução viável, pois abrange mais relações e uma área de mercado maior do que as soluções intermodais de dois terminais convencionais. Os terminais intermediários também implicam em um transporte rodoviário alimentador mais curto e mais frequente.

    O principal pré-requisito para fazer o trem da linha intermodal eficiente é um fluxo estável e equilibrado de bens com a utilização do espaço de carga otimizada ao longo da rota. Como o objetivo é consolidar pequenos fluxos, desequilíbrios ao longo da rota irão constituir um obstáculo para o trem da linha ser competitivo. (Woxenius 2007) citam várias medidas que podem ser tomadas a fim de superar esses desequilíbrios: adaptação da capacidade dos comboios, adaptar os tempos de partida, o uso de caminhões paralelos às linhas ferroviárias, adaptar as rotas de trem, atribuir terminais dinamicamente, aplicar incentivos de preços, melhorar a partilha de informação e aplicar sistemas de apoio à decisão. Outro pré-requisito para a linha intermodal treina para ser competitivo para os serviços rodoviários unimodal no transporte urbano é o tempo de transbordo tempo e custo-eficiente nos terminais (Behrends et al., 2012).

    A interface intermodal física consiste no transbordo de unidades de carregamento (LU), convencionalmente manuseadas com grantry-cranes ou reach-stackers. Estes tipos de terminais intermodais envolvem operações de alto volume, exigindo elevados custos de investimento e altas taxas de utilização, assim, em muitos casos, o número de terminais intermodais é pequeno e sua rede dispersa. Assim, o conceito de terminais intermodais eficientes de pequena escala foi estudado por (Kordnejad 2014), que consistem na utilização operacional de novas tecnologias de transbordo em terminais localizados ao lado do ramal ferroviário, muitas vezes tirando proveito de estações já existentes. A metodologia utilizada para avaliar a viabilidade do transporte intermodal é baseada em um modelo de custo de transporte que se baseia em métodos de cálculo do custo por atividade e destina-se como um modelo de apoio à decisão genérico com os custos como a função objetivo principal.

    Methodology

    A modelagem e simulação de redes intermodais de transporte se tornaram uma ferramenta importante para o planejamento de transportadores e embarcadores e como fundamento para a política e para o planejamento estratégico. A criação e o uso de modelos específicos é evidente, no entanto, uma abordagem mais geral, na perspectiva dos embarcadores é mais vantajosa, dado que é comumente os gerentes de lo