To sustain the development of maritime transportation, “green ports,” which operate with a good balance between environmental impact and economic interests, have been the focus of port operators and government agencies and are required to look into energy saving and emission reduction initiatives. One such reduction strategy proposed by the International Maritime Organization suggested imposing a carbon emission tax on ports as a long-term solution to reduce carbon emissions, but this would definitely increase the operating cost of ports. Quay cranes (QCs), as one type of handling equipment, play an important role in the service efficiency and carbon emission of ports. Therefore, this paper makes an effort to explore the study of the integrated berth allocation and QC assignment problem with the consideration of carbon emission taxation. This problem is formulated as a biobjective integer programming model, aimed at minimizing the total completion delay of all tasks and the total operating costs for all QCs. Finally, numerical experiments are performed to assess the applicability of the proposed models and evaluate the efficiency of the developed solution algorithm.

This paper addresses the deployment issue of emergency rescue stations in an urban transportation corridor, with an aim to effectively reduce the casualties in traffic accidents. On the basis of urban population density, an accident rate distribution function for a corridor is first presented and calibrated, and a damage cost function is proposed to capture the correlation between rescue time and deteriorating health condition of injured passengers. A continuum model is then developed for determining the optimal number and locations of the rescue stations along the corridor and the medical service resource distribution at rescue stations subject to a capital budget constraint. The solution properties of the proposed model are explored analytically. Numerical examples are provided to show the effects of population density, urban form and different deployment schemes (even and uneven) on the rescue station locations. A case study of Wuhan China is employed to illustrate the effectiveness of the proposed methodology in improving the performance of the emergency rescue system.

This paper provides a theoretical analysis of three alternative auto ownership rationing schemes, including lottery, auction and the hybrid scheme. The city's residents are differentiated by their income level, which is assumed to follow a uniform distribution. Expected social cost minimization models are proposed for determining the optimal auto quota for these schemes and the optimal proportion allocated to the lottery and auction in the hybrid scheme. The solution properties of the proposed models are analytically explored, and a comparison of these schemes is made. The results show that the auction scheme is most efficient and the lottery scheme is most inefficient in terms of the expected social cost. The optimal auto quota increases with degraded transit services, but decreases with increased auto travel time/cost. Increasing the proportion of allocation to the lottery in the hybrid scheme may lead to an increased or a decreased optimal auto quota, depending on the road service level. Residents' income gap can significantly affect the optimal quota solution: widening the income gap via raising the income of the rich pushes the government to increase the quota to be provided. However, narrowing the income gap via raising the minimum salary standard may require an increased or a decreased quota provision. The efficiencies of the lottery and auction schemes are very close in terms of the expected social cost, which justifies the use of the lottery scheme in practice.

This paper proposes a novel model of the design of a build-operate-transfer (BOT) contract for integrated rail and property (R + P) development when the size of future urban population is uncertain. A real-option approach is adopted to accurately capture the potential economic value of a BOT investment project under uncertainty and its externality effects on urban spatial structure. The proposed model is formulated as a two-stage problem. The first stage of the model optimizes the concession period and rail line parameters (including rail line length, and number and locations of stations) through a Nash bargaining game between a private investor and the government. The second stage determines the headways and fares during the private operation and after transferring the BOT project to the government. The private investor's objective is to maximize its own net profit received during the concession period, whereas the government aims to maximize social welfare over the whole life-cycle of the project. The proposed model is extended to explore the effects of future population jumps due to non-recurrent random events and station deployments with even and uneven station spacings. The results show that compared with the rail-only scheme, the R + P scheme can lead to a win-win situation for the government and private investor. In the BOT contract design, ignoring the effects of population jumps and using an average (or even) station spacing as an estimate of actual station deployment can cause a large bias of the parameter values designed in the contract and an underestimate of project values in terms of expected net profit and expected social welfare.

This study aims to determine the optimal vessel speed and ship fleet size for an industrial shipping service operating through the emission control areas (ECAs). To comply with the ECA regulation, the industrial shipping service operator can adjust its vessel speeds and fleet size to minimize the annual fleet cost, which includes the total fleet operating cost and in-transit cargo inventory cost. A mixed-integer convex cost-minimization model is developed for the determination of optimal vessel speeds and fleet size, in which the vessel speeds are continuous decision variables and the fleet size is an integer decision variable. The analytical optimal solution of the developed model is identified by relaxing the integer restriction of the fleet size variable. It is shown that how the in-transit cargo inventory cost can play a role in changing the way that the optimal vessel speed is identified. We also demonstrate that the minimal annual fleet cost could be attained by simply comparing two candidate analytical solutions. Numerical studies are carried out to investigate the economic and environmental impacts of the ECA regulation on several representative industrial shipping services. Recommendations are also provided on the proper modeling choice of fleet size in different contexts.

This paper addresses the development issue of interrelated rail transit projects in an urban rail transit network over multiple time periods. It extends the traditional network design problems by explicitly considering the time horizon and interrelations among investment projects in the rail transit network. The proposed model determines which projects in the rail transit network should be selected and completed at what times (i.e., project selection, investment sequence and completion time), while jointly optimizing the evolving headways of rail transit lines due to change in rail network configuration, so as to minimize the total discounted cost of the rail transit system over the planning horizon. In addition to the financial budget provided by relevant agencies (e.g., governments), we consider fare revenue generated from the operations of previous completed rail projects as an internal source of funding for later rail projects. A genetic algorithm is adapted to solve this model and tested on the rail transit network development of Wuhan China. Sensitivity analysis is conducted to ascertain the effects of some important factors on the development plan, such as travel demand and annual financial budget.

The prevalent airport slot policy, based on the grandfather rights and use-it-or-lose-it rule, may induce the so-called slot hoarding behavior, i.e., airline intentionally operates excessive or even unprofitable flights. This paper develops a vertical-structured model to explore the effects of such slot policy on airline’s service decisions (flight frequency, aircraft size and airfare) and airline profit, and the resultant implications for a profit-maximizing airport or a welfare-maximizing airport. The effects of airline competition on slot hoarding behavior are also examined with an oligopoly competition model in which the carriers provide horizontally differentiated flight services. Analytical solutions are derived and compared with the “no slot policy” scenario. We find that the claimed negative effects of the slot policy on airport congestion may be overstated since an airline chooses to hoard slots if and only if the demand/capacity ratio is significantly low. When the airline has to hoard slots by operating excessive flights, it would use smaller aircraft, charge a higher airfare and serve more passengers. For a private airport, the slot policy may increase the airport’s profit by allowing the airport to transfer some of the negative effects of weak travel demand to airlines. For a public airport, the slot policy does not decrease social welfare unless passengers’ valuation toward frequency benefit is low. Finally, for airlines with equal access to airport slots, as the substitutability among airlines and/or the number of competing airlines increases, the incentive of slot hoarding decreases. Hence, regulators may expect a much milder negative effect of slot hoarding in a competitive aviation market.

This paper presents a multimodal urban system equilibrium model to address cordon toll pricing and bus service design issues in a two-dimensional monocentric city. Commuters are assumed to travel by auto or bus from their home locations to their workplace located in the city center through a ring-radial routing system. Auto users must pay tolls when passing through the cordons installed on the radial major roads. The multimodal two-dimensional urban system equilibrium is first formulated and its properties are analytically explored. A social welfare maximization model that simultaneously determines the optimal cordon toll location, toll level, bus service frequency and fare on each radial major road is then proposed. The effects of different tolling schemes (uniform and differential cordon-based, first-best, and no toll) on the multimodal urban system are also examined and compared.

This paper investigates the design issues of a shipping network when cargo demand increases rapidly. A gravity-type model for origin-destination (OD) demand estimation is first presented and calibrated based on the current cargo volumes of the Indonesian maritime market. A model for maximizing total social welfare is then proposed to design the shipping network with cargo demand levels forecasted for future years. The results show that for the Indonesian maritime market, a hub-and-spoke network with fully connected hub ports is better than a network with sequentially connected hub ports in terms of total social welfare. The optimal choices for the international gateway and domestic hub ports vary as cargo demand increases over time. The results suggest that a progressive policy can be promising for infrastructure investments in developing countries: government planning and regulations may be introduced in early years to enhance infrastructure utilization and economic return. With increased demand the market may be liberalized to promote healthy competition.

This paper proposes an analytical model to determine the optimal cordon toll pricing scheme in a linear monocentric city with a competitive railway/highway system. It is assumed that the daily commuting time by rail mode is deterministic, while that by auto is stochastic and location dependent across the city. The travel time uncertainty could affect residents’ residential location choices and thus the urban spatial structure due to a long-term adjustment. In order to hedge against travel time variability on highway, commuters by auto often consider a travel time budget longer than the expected trip time to avoid late arrivals. It shows that ignorance of auto travel time variation may cause a significant bias in the prediction of the urban spatial structure in terms of residential distribution and city size. The implementation of cordon toll pricing scheme can rationalize the urban residential distribution and increase the social welfare of the urban system.