Development of a neighborhood commute mode share model using nationally-available data

Transportation - Practitioners often use demand models to predict how neighborhood-level land use, infrastructure, demographic, and other changes may impact transportation systems. Few of the...     

Time‐of‐day transit pricing: comparative US and international experiences

Experiences with time‐of‐day transit pricing in the U.S. are reviewed in this article and compared to those in other countries. Emphasis is placed on examining ridership, financial and efficiency impacts associated with time‐of‐day pricing, along with highlighting innovative approaches to implementing fare differentials. American time‐of‐day fare structures have been about evenly split between off‐peak discounts, peak‐period surcharges, and programmes involving differential rates of fare increases between peak and off‐peak hours. Although most American operators introduced time‐of‐day differentials to encourage ridership shifts to the off‐peak period, available evidence suggests that they have been only marginally successful in doing so. Off‐peak users were generally found to be far more fare‐sensitive to discounts than peak passengers were to surcharges. Only in a handful of American cities were significant efficiency and financial benefits from time‐of‐day pricing recorded, though in those few places, they tended to be substantial. The most successful American programmes have been those which collect fares on the basis of bus runs and direction of trips (rather than the exact time) and which aggressively market their programmes under the aegis of ‘bargain fares’. It is concluded that useful lessons can be gained by sharing policy insights from experiments with differential transit pricing in both the US and elsewhere.     

加拿大的城市轨道交通技术

加拿大幅员辽阔,但人口稀少(大约3000万人).由于气候地理的原因,90%的加拿大人居住在与美国邻界322 km宽的窄带内.另外,加拿大的大多数人,确切地说是76.6%,居住在城市和城镇,只有23.4%的人居住在乡村.因此,加拿大的城市发展问题十分重要.多伦多、蒙特利尔、卡尔加里、温哥华等城市已发展成为国际大都市,多种经济形式并存,服务业十分发达,还有银行、工程、医药和科学研究等.     

A model of traffic dispersion from a congested road

The study of traffic flow dynamics is developed by defining and clarifying traffic divergence, continuity, congestion and dispersion. Velocity potential is introduced as a gravity function generated by the interaction of two or more motorists occupying neighbouring points in space and describes interference to continuous traffic flow. The relationship between the potential function and carrying capacity is developed and dispersion, when considered as a random walk, satisfies a diffusion equation. A model of traffic dispersion along a maximum congested road in space and time is presented as eigenfunctions of the velocity potential. This suggests that traffic can be dispersed by a series of quantum steps. A probability density function is introduced to define the probability of locating a motorist in a congestion zone.     

Strategic alliances in the container shipping industry: a global perspective

This paper examines developments in container shipping in light of the formation of strategic alliances by many of the leading companies. It focuses on three features: the transformation of services, the evolution of the fleet, and the adjustments made to the ports of call. These elements are analysed on a global basis for 3 years: 1989, 1994 and 1999. Some of the changes wrought by the alliances are identified, including the spread and intensification of services, and the deployment of the largest vessels on alliance routes. While the individual companies that have come together in alliances are serving many more ports than before, it is also demonstrated that the total number of ports served by the industry has remained constant. The results are interpreted in the context of globalization that is tending to impose greater standardization on the container shipping industry.     

Alternatives in assigning short‐term counts to seasonal adjustment factor groupings

The precise estimation of the annual average daily traffic (AADT) is a task of significant interest for many transportation authorities and Departments of Transportation. In this study, three methods are developed to improve the assignment of short‐term counts to seasonal adjustment factor (SAF) groupings: the traditional functional classification, a discriminant analysis (DA), and a new statistical approach based on a weighted coefficient of variation (WCV). The data analyzed within this study are generated from all available continuous counters within the State of Ohio between 2002 and 2006. The analysis is conducted using SAFs that are separately calculated for the total volume and the directional specific volumes of a site. The results show that the directionally based assignment errors are statistically lower at a 95% confidence interval when compared with those generated by the total volume analysis. It is also found that the hourly time‐of‐day factors are more important in the assignment process than the average daily traffic. The directionally based WCV produces a decline in the average mean absolute percentage error (MAPE) over the roadway functional classification by 58% and in the standard deviation of the absolute error (SDAE) by 70%. On the contrary, the directionally based DA lowers the MAPE and the SDAE by 35% and 60%, respectively. Copyright © 2012 John Wiley & Sons, Ltd.     

State vs. national interests in an expanded territorial sea

Abstract

The recently adopted Law of the Sea (LOS) Convention contains a provision allowing coastal nations to adopt 12‐mile territorial seas. Already 104 nations (of a total of 137 coastal nations) have claimed territorial seas of 12 miles or wider. The paper discusses the factors which, in the opinion of the authors, could cause the United States to broaden its territorial sea from the present 3 miles to 12 miles within the next half‐dozen years or so. The state‐federal ocean use and resource management issues that will be raised by such a move are reviewed and options for dealing with the jurisdictional issues are developed. Given the political and economic volatility of these issues and their complexity, the use of a broadly representative and well‐staffed study commission to formulate a course of action is suggested.     

Challenges in Collaborative Governance for Coastal Restoration: Lessons from the Caernarvon River Diversion in Louisiana

In an effort to restore deteriorating coastal wetlands in Breton Sound, Louisiana, a diversion of Mississippi River water into the estuarine ecosystem has been operated at Caernarvon, Louisiana, since 1991. The diversion was implemented after a relatively long collaborative planning process beginning in the 1950s. The Caernarvon Interagency Advisory Committee, an official panel of stakeholders, considers scientific aspects of the freshwater inflow and stakeholder inputs in developing an operational plan, which internalizes stakeholder conflicts, while accomplishing goals of restoring the coastal ecosystem. Even though fishery representatives are committee members, local oyster fishers filed lawsuits in federal and state courts from 1994 through 2005, claiming damages to their oyster beds. These lawsuits were initially successful in state courts but were reversed by the Louisiana Supreme Court. The federal suits were unsuccessful. Following these lawsuits, voters in Louisiana in 2000 amended the State Constitution to protect coastal restoration projects against lawsuits reflecting increase in overall statewide support. Increasing scientific knowledge has contributed significantly to diversion operation. For better collaborative governance, efforts to increase common understanding among stakeholders will be needed, and a process to compensate interests of stakeholders suffering from impacts of restoration projects at an earlier stage should be institutionalized.     

How reliable is the bureau of motor carrier safety truck accident data?

This paper examines the degree of compliance with the accident reporting requirements imposed by the Bureau of Motor Carrier Safety (BMCS) of the U.S. Department of Transportation on motor carriers involved in interstate and foreign transport. It also examines the reliability and validity of the accident information reported by these carriers to the BMCS. The study shows that there is a high degree of accident underreporting, especially by the private and exempt carriers, and that the information reported on variables such as cargo weight, gross vehicle weights, and usage of seat belts at the time of accident, is biased toward the interests of the reporters of the accidents.     

热沥青灌浆工法于地下工程涌水处理的应用

热沥青灌浆工法除了应用于隧道内的巨量涌水处理外,在地下建筑结构大量涌水之改善处理工作上,也完成一颇具参考价值的实例.此两件案例的工作条件、涌水行为及施工设备均差异极大,然而在同一工法及材料的操作原理下,均得到了显著的成效.依据此两件特殊工程案例的应用经验,以及沥青浆材的物理特性,总结了沥青灌浆工作的基本操作特性及应用原则,以供其它类似涌水案例之应用参考.