Exploring ride-hailing fares: an empirical analysis of the case of Madrid

Transportation - Ride-hailing is an emerging service that is transforming door to door mobility in urban areas. Users can easily request a ride through a smartphone app that informs them of the...     

Steering short-term demand for car-sharing: a mode choice and policy impact analysis by trip distance

Transportation - Car-sharing could have substantial benefits. However, there is not enough evidence about if more people choosing car-sharing would reduce private car usage or public transport...     

The Gothenburg congestion charges: cost–benefit analysis and distribution effects

This paper performs an ex-post cost–benefit and distribution analysis of the Gothenburg congestion charges introduced in 2013, based on observed effects and an ex-post evaluated transport model. Although Gothenburg is a small city with congestion limited to the highway junctions, the congestion charge scheme is socially beneficial, generating a net surplus of €20 million per year. From a financial perspective, the investment cost was repaid in slightly more than a year and, from a social surplus perspective, is repaid in < 4 years. Still, the sums that are redistributed in Gothenburg are substantially larger than the net benefit. In the distribution analysis we develop an alternative welfare rule, where the utility is translated to money by dividing the utility by the average marginal utility of money, thereby avoiding putting a higher weight on high-income people. The alternative welfare rule shows larger re-distribution effects, because paying charges is more painful for low-income classes due to the higher marginal utility of money. Low-income citizens pay a larger share of their income because all income classes are highly car dependent in Gothenburg and workers in the highest income class have considerably higher access to company cars for private trips. No correlation was found between voting pattern and gains, losses or net gain.

     

An integrated framework for embedding large-scale dynamic traffic assignment models in advanced traveler information systems

In recent years, increasing attention has been drawn to the development of various applications of intelligent transportation systems (ITS), which are credited with the amelioration of traffic conditions in urban and regional environments. Advanced traveler information systems (ATIS) constitute an important element of ITS by providing potential travelers with information on the network's current performance both en-route and pre-trip. In order to tackle the complexity of such systems, derived from the difficulty of providing real-time estimations of current as well as forecasts of future traffic conditions, a series of models and algorithms have been initiated. This paper proposes the development of an integrated framework for real-time ATIS and presents its application on a large-scale network, that of Thessaloniki, Greece, concluding with a discussion on development and implementation challenges as well as on the advantages and limitations of such an effort.     

On the income elasticity of the value of travel time

Transport infrastructure is long-term and in appraisal it is necessary to value travel time savings for future years. This requires knowing how the value of time (VTT) will develop over time as incomes grow. This paper investigates if the cross-sectional income elasticity of the VTT is equal to inter-temporal income elasticity. The study is based on two identical stated choice experiments conducted with a 13 year interval. Results indicate that the relationship between income and the VTT in the cross-section has remained unchanged over time. As a consequence, the inter-temporal income elasticity of the VTT can be predicted based on cross-sectional income elasticity. However, the income elasticity of the VTT is not a constant but increases with income. For this reason, the average income elasticity of the VTT in the cross-sections has increased between the two survey years and can be expected to increase further over time.     

In situ colonization of marine biofilms on UNS S32760 duplex stainless steel coupons in areas with different water qualities: Implications for corrosion potential behavior

In the presence of biofilms, stainless steels （SS） exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential （Eco,） behavior of the duplex SS UNS S32760 was recorded simultaneously with the in situ marine biofilm formation in two areas at Arraial do Cabo, Southeastern Brazil. The biofilm at Forno Harbor （an anthropogenically disturbed area） was characterized by higher relative abundances of Bacteria at day 2, followed by diatoms （especially Navicula sp.） on day 10 and dinoflagellates on day 18, whereas no clear trend was recorded at Cabo Frio Island （an undisturbed area）. The ennoblement of Ecor values was site-dependent. In a complementary laboratory assay, biofilms were removed and the Eco values registered in sterile conditions for the subsequent 10 days and corroborated in situ results. Understanding biofilms and SS interactions has important implications for materials science and engineering decisions as well as helping to fill in imnortant gaps in this knowledge.     

Economic efficiency in Spanish ports: some empirical evidence

In this study, a stochastic frontier cost function is used to estimate the econmic efficiency of Spanish ports through panel data. The sample covers annual data of 27 Spanish ports from 1985–1989. By comparing a Cobb-Douglas function with a translog, it is found that the latter best represents the technology according to the data. Analysing the efficiency indices obtained, it is found that the relatively larger ports are more economically inefficient. Moreover, the presence of large scale economies has been detected, as well as a lack of technical progress for the period considered.     

A model for forecasting future supply of shipping services at Australian ports

This paper aims to develop an integrated model for forecasting both the number of ship visits and their characteristics in the medium and long term. Knowledge of future shipping trends for any port is no doubt important, as the future number of ship visits and their characteristics may have implications for the physical facilities of a port. In addition, more reliance on tonnages as a revenue source has made this knowledge more valuable. The proposed model identifies such major economic determinants as the expected trade throughput, world shipping trends, standards of facilities and future plans of shipping companies/agents. The model examines three possible scenarios for the Port of Melbourne and produces a range of shipping forecasts based on certain assumptions. From the model the major findings were:

world trends in shipping did not have any immediate impact on the shipping trends at the Port of Melbourne;

Future shipping services at the Port of Melbourne in the next 11 years are most likely to be determined by trade demand rather than by technological developments overseas;

there has been no evidence to indicate that the Port of Melbourne has been excluded from the schedule of general cargo ships due to the Port's physical constraints.     

Service-oriented computing and model-driven development as enablers of port information systems: an integrated view

Port information management is considered a critical instrument towards enabling international transport and trade; thus, various forms of Port Information Systems (PORTIS) have been developed today, namely Port Community Systems, Terminal Operating Systems and Single Window systems. In Europe, the nautical information system SafeSeaNet is viewed as an important e-infrastructure. PORTIS systems are expected to evolve into next-generation technological platforms in order to offer a fully integrated digital environment to a multitude of maritime business actors and public authorities towards more efficient, safe and environment-aware transport and trade infrastructures and services. We propose service-oriented computing and model-driven development techniques as a robust PORTIS modelling and development approach. We present a reference model of PORTIS and a particular enabling methodological and technological framework. The proposed approach has been tested in a maritime single-window case.     

Cultural diversity, manning strategies and management practices in Greek shipping

The present paper examines the way Greek shipping companies and Greek seafarers perceive culture, and how this affects their approach to crew management and operation of the ships. The analysis focuses on the manning strategies employed by the companies, on the operational problems that might occur on-board, and on any possible disturbance of the relation between the ship, the office at shore and third parties. Finally, a number of management practices which, when implemented, help to overcome these problems is also examined. The research methodology includes a review of the existing literature and interviews conducted by means of questionnaires filled in by crew managers and seafarers. Results show that some of the predominant problems encountered aboard, as far as communication with multicultural crews is concerned, are rooted in cultural and linguistic incompatibility, as well as in inadequate and inappropriate training. Furthermore, crew managers and seafarers lack both a clear perception of culture, and share opinions on the implementation of manning strategies. The present paper concludes that culture management can enhance crew team cohesion, upgrade communication at all levels, and, finally, improve the quality of the working environment, the safety of the workplace and the overall performance of the team.