Analysis of Trends in Commuter Rail Energy Efficiency
Commuter rail systems are widely regarded as an effective transportation alternative to reduce energy consumption and emissions in large urban areas. Use of commuter rail systems in the United States is on the rise, with annual ridership increasing by 28 percent between 1997 and 2007 [1]. With growing concerns about the sustainability and environmental impacts of transportation, modal energy efficiency is increasingly considered amongst the metrics to evaluate the benefits and costs of transportation systems and justify future investment. To gauge the relative long-term efficiency trends for rail as an urban transportation mode, this study analyzes historic trends in energy efficiency metrics for US commuter rail systems. Commuter rail systems receiving, or benefiting from, Federal Transit Administration (FTA) grants are required to report operations and energy consumption data on an annual basis to the National Transit Database (NTD). NTD data on energy consumption, operations, and services supplied from 1997 to 2011 are analyzed to determine historic trends in various energy efficiency metrics for the commuter rail mode as a whole. The data analysis and comparison of the results with the highway mode is complicated by the use of electric traction by some commuter rail operators. These operators report energy consumption in purchased electricity (kWh) instead of gallons of liquid fuel. The different approaches that can be employed to compare these two forms of propulsion and their intrinsic efficiencies and energy sources are discussed. Energy efficiency of each commuter rail system and its relationship to individual system characteristics during the study period are also analyzed. Finally, case studies of historic energy efficiency of individual commuter rail systems with longer operating histories and reporting data over the majority of the study period are contrasted against more recent start-up systems. While many systems outperform the energy efficiency of a typical light-duty vehicle, there are others that, due to a variety of system parameters and characteristics, fail to achieve a load factor great enough to make them more attractive than the highway mode on a gross average level. It is hoped that highlighting trends and variation in commuter rail energy efficiency will allow policymakers to make more informed decisions regarding the environmental benefits of rail as an urban transportation mode.Copyright © 2014 by ASME
Methods of Analyzing and Comparing Energy Efficiency of Passenger Rail Systems
Because of growing concerns about the future environmental impact of passenger travel, modal energy efficiency is becoming increasingly important when benefits and costs of transportation system investment are evaluated. Because passenger rail systems are often cited as being relatively more energy efficient than other modes, reduced environmental impact is one justification for investment in new commuter rail projects. It is important that studies of purported environmental benefits analyze the energy efficiency of passenger rail systems and competing modes accurately and fairly by clearly defining the flow of energy through each transportation system. Furthermore, operational practices and constraints of the railway environment can complicate the analysis of energy efficiency; this complication makes it important to choose metrics that accurately describe the situation. This research identifies and describes four methods for analyzing the energy efficiency of passenger rail systems. Each method applies to a different system within the energy flow path. The combined methods are used to analyze the energy efficiency of 25 commuter rail systems in the United States. The results of each energy efficiency calculation method are then compared to illustrate how the relative attractiveness of each system can change on the basis of the selected analysis approach. By better understanding the challenges of conducting energy efficiency analyses involving different energy sources and fair comparison methods, researchers and policy makers can make informed decisions concerning the most appropriate method of analysis for drawing accurate comparisons between rail technologies and competing modes.
American Transportation Policy
An Overview of American Transportation Policy, 1789 to 1956 Highway and Mass Transit Policy, 1956 to 1990 Highway and Mass Transit Policy Today, ISTEA and TEA-21, The Intermodal Solutions Amtrak: Its Struggle for Survival and Respect The Civilian Air Transportation System The Future of American Transportation Policy Bibliography Index