Bridge and tunnel toll elasticities in New York

In 1992, the authors carried out a statistical analysis of Triborough Bridge and Tunnel Authority (TBTA) crossings in New York City, to determine the impact of toll increases on traffic volumes and revenue. Using twelve years of monthly time-series data, we developed a set of multiple regression models that estimated traffic volumes on each TBTA bridge and tunnel as a function of the toll level and other explanatory variables. In most cases, the estimated toll elasticities were negative and much less than 1.0 in absolute value; the median toll elasticity for automobiles was found to be –0.10. Our finding that automobile travel demand is highly inelastic with respect to toll rates is consistent with most previous travel demand studies.     

TOD与可持续发展

以世界几个城市的交通发展案例为基础,探讨TOD的实施及其发展趋势.首先以巴西库里蒂巴、圣保罗,瑞典斯德哥尔摩,美国旧金山湾区为例,探讨了TOD的3D原则:高密度开发、多元化土地利用和良好的设计.强调TOD不应局限于对公共交通车站和枢纽的开发,而是由一个点的开发到以公交为导向的走廊,进而发展至整个区域.以瑞典斯德哥尔摩、...     

Influence of wheel and rail profile shape on the initiation of rolling contact fatigue cracks at high axle loads

The influence of wheel and rail profile shape features on the initiation of rolling contact fatigue (RCF) cracks is evaluated based on the results of multi-body vehicle dynamics simulations. The damage index and surface fatigue index are used as two damage parameters to assess the influence of the different features. The damage parameters showed good agreement to one another and to in-field observations. The wheel and rail profile shape features showed a correlation to the predicted RCF damage. The RCF damage proved to be most sensitive to the position of hollow wear and thus bogie tracking. RCF initiation and crack growth can be reduced by eliminating unwanted shape features through maintenance and design and by improving bogie tracking.     

The public administrator: Regulating for maritime transport efficiency

One role often fulfilled by public administrators is to regulate private enterprise in the public interest. The academic literature has not developed this area fully because public administration is not always tasked with this function. Nevertheless, when regulation forms a part of the responsibilities of the public administrator, it is among the most important. An essential foundation for effective regulation is a complete understanding of the implications and impact of regulatory action. In the absence of regulation, entrepreneurial awareness is applied in the private sector exclusively to satisfying consumer wants. In a regulated market, the entrepreneur’s focus is shifted toward regulatory imperatives. Regulation offers non-market opportunities for entrepreneurial innovation, as well as imposing new market constraints. This paper examines regulation of the maritime industry by the US federal government as an example.     

Strategic alliances in container liner shipping

The economic crisis in the years between 2008 and 2010 has demonstrated the necessity for substantial adjustments on behalf of container lines. Capacities were shifted quickly to emerging and less affected markets allowing a faster recovery of globally organized companies. This paper illustrates the dynamics in the container shipping market. Alongside the main characteristics of the Top 20 ocean shipping companies, liner services are described. These services are classified by geographic coverage and vessel deployment. In addition, this paper provides a better understanding of the collaboration among service providers. Starting from a general framework of co-operative liner services, in-depth analyses of the global alliances in liner shipping are obtained. These formations - Grand Alliance, New World Alliance and CKYH Alliance - are compared with alternative forms of collaboration in the liner shipping industry. The analysis of alliance announcements which are related to operational and strategic changes indicates that the “global alliances” cannot be regarded as closed corporate-like entities. In effect, service agreements are not only negotiated with the focal members of the specific alliance. Instead, every service is arranged individually and under specific conditions. By understanding the dynamics within alliances, we are able to develop an assessment relating to the stability of collaborations. Ultimately, these insights direct us to several paths for future research.     

A Practical Model for Deformation Prediction of Highway Subgrade Soils

This paper reports a practical constitutive relation for highway subgrade soils. The proposed model is derived based on the laboratory repeated-load testing of four subgrade soils. Statistical parameters generally used in the power model of subgrade permanent strain are expanded into material constants with engineering significance. The constitutional relation reported in this paper can be used in the mechanistic-based pavement design of highway flexible pavements and railroad tracks.     

The impact of weather conditions on bikeshare trips in Washington,DC

Bicycle usage can be affected by colder weather, precipitation, and excessive heat. The research presented here analyzes the effect of weather on the use of the Washington, DC, bikeshare system, exploiting a dataset of all trips made on the system. Hourly weather data, including temperature, rainfall, snow, wind, fog, and humidity levels are linked to hourly usage data. Statistical models linking both number of users and duration of use are estimated. Further, we evaluate trips from bikeshare stations within one quarter mile of Metro (subway) stations at times when Metro is operating. This allows us to determine whether Metro serves as a back-up option when weather conditions are unfavorable for bicycling. Results show that cold temperatures, rain, and high humidity levels reduce both the likelihood of using bikeshare and the duration of trips. Trips taken from bikeshare stations proximate to Metro stations are affected more by rain than trips not proximate to Metro stations and less likely when it is dark. This information is useful for understanding bicycling behavior and also for those planning bikeshare systems in other cities.     

The Bathside Bay story

In this article the author considers whether an opportunity to develop harbour facilities at a strategically located site in Harwich Harbour on the east coast of England may have been missed in the 1960s and 1970s. The complications of divided ownership and powers to develop the site are explained; and successive attempts to obtain Government approval for harbour development under section 9 of the Harbours Act 1964 (since repealed) are described. The effective operation of that control in this case, influenced at one stage by political considerations, is questioned.