Compound Poisson—Gamma Regression Models for Dollar Outcomes That Are Sometimes Zero

2012 ◽  
Vol 20 (3) ◽  
pp. 387-399 ◽  
Author(s):  
Benjamin E. Lauderdale

Political scientists often study dollar-denominated outcomes that are zero for some observations. These zeros can arise because the data-generating process is granular: The observed outcome results from aggregation of a small number of discrete projects or grants, each of varying dollar size. This article describes the use of a compound distribution in which each observed outcome is the sum of a Poisson—distributed number of gamma distributed quantities, a special case of the Tweedie distribution. Regression models based on this distribution estimate loglinear marginal effects without either the ad hoc treatment of zeros necessary to use a log-dependent variable regression or the change in quantity of interest necessary to use a tobit or selection model. The compound Poisson—gamma regression is compared with commonly applied approaches in an application to data on high-speed rail grants from the United States federal government to the states, and against simulated data from several data-generating processes.

2021 ◽  
Vol 13 (11) ◽  
pp. 6456
Author(s):  
Ziqi Liu ◽  
Ming Zhang ◽  
Liwen Liu

There have been growing concerns around the world over the rising spatial inequality (SI) amid fast and vast globalization. This paper presents an effort to benchmark the conditions and trends of spatial inequality in 37 megaregions in the United States, Europe, and China. Furthermore, the study selected three megaregion examples and analyzed the effect of developing high-speed rail (HSR) as an infrastructure investment strategy on reshaping the spatial pattern of job accessibility. The study measures spatial inequality with the Theil index of gross regional product and with the rank-size coefficient of polycentricity. Results show that spatial inequality exists and varies in magnitude within and between megaregions. On average, Chinese megaregions exhibited the level of spatial inequality about two times or more of those in the U.S. and European megaregions. The decade between 2006 and 2016 saw a decrease in the Theil index measure of megaregional inequality in China, but a slight increase in the United States and Europe. Fast growing megaregions exhibit high levels and rising trends of spatial inequality regardless of the country or continent setting. HSR helps improve mobility and accessibility; yet the extent to which HSR reduces spatial inequality is context dependent. This study presents a first attempt to assess and compare the spatial inequality conditions and trajectories in world megaregions aiming at promoting international learning.


Author(s):  
Jeff Morales

California has started construction on the first true high-speed rail system in the United States. In this chapter, the CEO of the California High-Speed Rail Authority describes how the state's historic investment in new high-speed rail infrastructure will benefit Californians. Benefits include job creation, statewide modernization of existing local rail lines, short and long-term reductions in greenhouse gas emissions, preservation of agricultural land and environmentally sensitive habitats, advanced clean and green construction practices and technologies, a commitment to 100% renewable energy use, and assistance to partner cities on transit-oriented planning for high-speed rail station areas.


Author(s):  
V. Dimitra Pyrialakou ◽  
Konstantina (Nadia) Gkritza

The development of a nationwide commuter and high-speed rail (HSR) network has been suggested as a promising and “greener” passenger transport solution with the potential to reduce energy consumption and greenhouse gas emissions, given efficient planning that will ensure sufficient ridership and sustainable investment. It is anticipated that passenger rail growth will bring regional economic benefits as well as promote energy independence, transportation safety, and livable communities with improved accessibility and inter-connectivity. Much research has been conducted to identify the benefits and costs associated with the operation, maintenance, and improvement of passenger rail services. However, previous studies supporting investment in passenger rail have generally considered one evaluation factor at a time. Additionally, studies suggesting that investment in passenger rail is not cost-effective give more weight to quantifiable benefits and current conditions, and rarely consider changes in public preferences influenced by policies and fostered conditions to encourage mode shifts. Thus, the literature lacks a comprehensive approach that would evaluate investments in passenger rail, accounting for quantifiable and other benefits, in light of environmental, resilience and sustainability, economic, demand, and feasibility factors. Using a case study of the Hoosier State line, this study illustrates a systems approach for comprehensively assessing passenger rail services in the United States in terms of the system’s existing opportunities and future directions. The Hoosier State line operates four days per week between Indianapolis, Indiana and Chicago, Illinois with four intermediate stops. As of October 1, 2013, the State of Indiana, local communities, and Amtrak reached an agreement to support the Hoosier State line for the next fiscal year (2013–2014).


Author(s):  
Zhenhua Chen

In this study, we focus on the Acela Express, and try to find out how selected internal and external factors affect the Acela Express’s ridership. A two-stage least square regression model is introduced in order to eliminate the endogeneity problem caused by price and ridership. Also the Cochrane-Orcutt Procedure is adopted to solve autocorrelation. The result shows that ticket price and train on-time performances, which are used to being thought as important factors affect ridership become insignificant, while other factors like employment of business and professional in the Northeast Corridor areas have higher influence on high speed train ridership. The broader objective of this research is to provide policy suggestions for building of an efficient high-speed rail network that can both be profitable and solve practical problems that the contemporary transportation system faces.


Author(s):  
Inna N. Rykova ◽  
Andrey A. Alaev

The article is devoted to the experience of the implementation of high-speed railways in foreign countries and the possibility of its use in Russia. Particular attention is paid to the issues of financial and economic justification of such projects, using the criteria of commercial and budgetary efficiency. Particular attention is paid to China in the article, since this country today has the greatest experience in the implementation of projects in the field of high-speed rail communication. The emergence of high-speed rail in China not only became a technological breakthrough, but also played an important role in stimulating the country’s economy and enhancing domestic demand. At the moment, 57% of all high-speed railways in the world are in China alone. The experience of the United States is also of scientific interest, in particular, in the consideration and evaluation of high-speed rail projects. Despite the high level of economic development in the United States, high-speed rail transport is practically undeveloped, which is largely due to historical reasons. Cheap oil, along with improvements to cars and airplanes, and government subsidies for highway and airport construction, have made these vehicles more accessible to most of the population and highlighted them. Despite these circumstances, the authorities of many states are interested in the implementation of high-speed rail projects. At the same time, the question of the possibility and expediency of switching passenger flows from existing modes of transport remains relevant in the United States. In the final part of the article, using the example of specific projects, the prospects for the development of high-speed railway communication in Russia are assessed and proposals for the development of the transport complex as a whole are given.


Author(s):  
Adrian Hellman ◽  
Tashi Ngamdung

The United States Department of Transportation’s (USDOT) Research and Innovative Technology Administration’s John A. Volpe National Transportation Systems Center (Volpe Center), under the direction of the USDOT Federal Railroad Administration (FRA) Office of Research and Development (ORD), conducted a reliability analysis of the four-quadrant gate/vehicle detection equipment installed on the potential high-speed rail (HSR) corridor between Chicago and St Louis. A total of 69 highway-rail grade crossings on a 121-mile (195 km) segment of the 280-mile corridor were equipped with four-quadrant gates and inductive loop vehicle detection technology. This segment, between Mazonia and Springfield Illinois, may eventually carry passenger trains at speeds up to 110 mph (177 km/h), including at many of the highway-rail grade crossings. The analysis was based on maintenance records obtained from the Union Pacific Railroad (UPRR), the owner and operator of the rail line. The results were used to assess the impact of the equipment reliability on the proposed HSR timetable. The Volpe Center study showed that the total average delay to the five scheduled daily high-speed passenger roundtrips was an estimated 10.5 minutes, or approximately one minute per train. Overall, extensive analysis of the trouble ticket data showed that the four-quadrant gate and vehicle detection equipment had a minimal direct impact on the frequency and duration of grade crossing malfunctions.


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