How quickly the US can decarbonize light-duty vehicle (LDV) transportation depends on the rates of change of electric vehicle (EV) sales, stock turnover, and grid decarbonization. We build a stock turnover model to assess how sensitive achieving 2050 LDV decarbonization targets is to these rates. We estimate carbon dioxide (CO _2 ) reductions of 70%–85% by 2050, including emissions from vehicles and upstream electricity generation, provided that new vehicle sales transition to 100% EVs and substantial grid decarbonization are accomplished by 2050. This result is robust to continuation of long-term trends of increasing vehicle longevity, and to whether the timing of EV sales growth and grid decarbonization are coordinated. If the two key goals are met, the annual contribution of EV electricity use to CO _2 emissions will be small over the entire period.

Hydrogen can power transportation with near zero greenhouse gas emissions. With government support, early market development is now underway in several nations thanks to technological advances in fuel cell vehicles and electricity generation from renewable energy. Deploying a sustainable hydrogen refueling infrastructure faces methodological and practical challenges ranging from the creation of appropriate codes to managing the co-evolution of the refueling network and growth of the stock of hydrogen fuel cell vehicles. This paper presents a comprehensive review of the challenges facing the designing, planning and deployment of hydrogen refueling infrastructure progress to date and outlook for the future. The design and costs of refueling infrastructure as well as the lifecycle environmental effects of hydrogen vehicles depend on how hydrogen is produced and delivered to refueling stations. In recent years, important advances have been made in methods for planning the numbers, sizes and location of hydrogen stations. Institutional barriers are also gradually being overcome. Co-evolving the deployment of stations and the demand for fuel cell vehicles remains a crucial subject for future research.

As standards for vehicle greenhouse gas emissions and fuel economy have become more stringent, concerns have arisen that the incorporation of fuel-saving technologies may entail tradeoffs with other vehicle attributes important to consumers such as acceleration performance. Assessing the effects of these tradeoffs on consumer welfare requires estimates of both the degree of the tradeoffs, and consumer willingness to pay (WTP) for the foregone benefits. This paper has two objectives. The first is to review recent literature that presents, or can be used to calculate, marginal WTP (MWTP) for vehicle attributes to describe the attributes that have been studied and the estimated MWTP values. We found 52 U.S.-focused papers with sufficient data to calculate WTP values for 142 different vehicle attributes, which we organized into 15 general groups of comfort, fuel availability, fuel costs, fuel type, incentives, model availability, non-fuel operating costs, performance, pollution, prestige, range, reliability, safety, size, and vehicle type. Measures of dispersion around central MWTP values typically show large variation in MWTP values for attributes. We explore factors that may contribute to this large variation via analysis of variance (ANOVA) and find that, although most have statistically significant effects, they account for only about one third of the observed variation. Case studies of papers that provide estimates from a variety of model formulations and estimation methods suggest that decisions made by researchers can strongly influence MWTP estimates. The paper's second objective is to seek consensus estimates for WTP for fuel cost reduction and increased acceleration performance. Meta-analysis of MWTP for reduced fuel cost indicates that estimates based on revealed vs. stated preference data differ, as do estimates from models that account for endogeneity and those that do not. We find greater consistency in estimates of MWTP for acceleration despite substantial uncertainty about the overall mean. We conclude with recommendations for improving the understanding of consumers' MWTP for vehicle attributes.

Following a tripling of world oil prices in 1973-74, the U.S. Congress passed the Energy Policy and Conservation Act of 1975 establishing mandatory fuel economy standards for automobiles and light trucks. Beginning at 18 MPG in 1978, the passenger car standards increased to 27.5 MPG by 1985. There has been considerable debate about the influence of the standards, as opposed to the gasoline price increases in 1973-74 and 1979-80, on new car fuel economy. Twelve years of average fuel economy data are now available for every manufacturer’s domestic and imported car fleets, making possible a statistical estimation of the relative importance of standards versus fuel prices in determining new car MPG. In this paper a penalty function is formulated in which deviations from either the standard or the market equilibrium demand for fuel economy create costs for manufacturers. An equation for new car MPG is derived by minimizing the sum of quadratic penalty functions. Estimation of the model, using 15 sets of manufacturer CAFE data for 1978-89, clearly indicates that the CAFE standards were a significant constraint for many manufacturers, and were perhaps twice as important an influence as gasoline prices. A test for structural change in the model does not reject the hypothesis that the CAFE constraint had the same effect on carmakers before and after 1983.

Understanding the fuel economy of vehicles in actual use has important implications for fuel economy, greenhouse gas emission and consumer information policies. This study explores how fuel economy varies with intensity of daily vehicle use, cumulative mileage, and ambient temperature. Using a unique longitudinal database, we quantify variations in fuel economy (miles per gallon or MPG). over time for the same vehicle. The database consists of more than 600,000 odometer and fuel purchase records, obtained from the "My MPG" section of the http://fueleconomy.gov website. Over 10,000 drivers reported their fuel purchases and vehicle usage, with an average of 36 fill-ups per vehicle. Multilevel models are used to analyze and compare relationships for conventional gasoline and hybrid vehicles. For gasoline vehicles, within-vehicle variation accounts for 23% total variation of fuel economy and 77% is between-vehicle variation. For hybrids, the equivalent proportions are 19% and 81%. On-road fuel economy increases nonlinearly with cumulative mileage, with nearly all of the increase occurring within the first few thousand miles. The estimated trend for hybrid vehicles is very different from that of conventional gasoline vehicles. Hybrids were found to have higher daily miles of use than conventional gasoline vehicles. Cold temperatures appear to have a greater effect on the fuel economy of hybrids than conventional gasoline vehicles. (C) 2017 Published by Elsevier Ltd.

U.S. government fuel economy tests are used for two primary purposes: 1) to monitor automobile manufacturers’ compliance with fuel economy and greenhouse gas emissions standards and 2) to inform consumers about the fuel economy of passenger cars and light trucks. This study analyzes a unique database of 75,000 fuel economy estimates self-reported by customers of the U.S. government website www.fueleconomy.gov to evaluate the effectiveness of the government's estimates for these two purposes. The analysis shows great variability in individuals’ own fuel economy estimates relative to the official government estimates with a small bias relative to the sample average. For consumers, the primary limitation of government fuel economy estimates is imprecision for a given individual rather than bias relative to the average individual. The analysis also examines correlations between individuals’ fuel economy estimates and specific technologies, vehicle class, driving style, method used to calculate fuel economy, manufacturer, and state. Gasoline, hybrid and diesel vehicles were separately evaluated. There is some evidence that the shortfall between test cycle fuel economy estimates (used to measure compliance with regulations) and in-use fuel economy estimates (such as those provided by customers of www.fueleconomy.gov) has been increasing since 2005. If this trend continues, it could affect the benefits realized by fuel economy and greenhouse gas emissions standards. A scientifically designed survey of in-use fuel economy is needed to insure that an unbiased sample is collected and that fuel economy is rigorously and consistently measured for all vehicles. The potential for information technology to enable more precise prediction of individual fuel economy should be explored.

On a per-capita or per-vehicle-mile-traveled (VMT) basis, Tennessee spends less than almost any other state on its highways and roads. Fuel tax rates are among the lowest in the nation and transportation-related debt is nonexistent. Compared to other states, roadway dollars have been far less plentiful. Nonetheless, in spite of this austerity, Tennessee has planned, built, and continues to maintain a roadway network that has better pavement, better bridges, and less congestion than most other comparable state systems. However, concerns are mounting that these outcomes are at risk due to a funding outlook that continues to deteriorate. This policy brief looks at the funding of Tennessee roadways, roadway revenue outlook, and potential policy responses.

The importance of reducing U.S. oil dependence may have changed in light of developments in the world oil market over the past two decades. Since 2005, increased domestic production and decreased oil use have cut U.S. import dependence in half. The direct costs of oil dependence to the U.S. economy are estimated under four U.S. Energy Information Administration Scenarios to 2040. The key premises of the analysis are that the primary oil market failure is the use of market power by OPEC and that U.S. economic vulnerability is a result of the quantity of oil consumed, the lack of readily available, economical substitutes and the quantity of oil imported. Monte Carlo simulations of future oil market conditions indicate that the costs of U.S. oil dependence are likely to increase in constant dollars but decrease relative to U.S. gross domestic product unless oil resources are larger than estimated by the U.S. Energy Information Administration. Reducing oil dependence therefore remains a valuable goal for U.S. energy policy and an important co-benefit of mitigating greenhouse gas emissions.

Increased domestic petroleum supply and decreased consumption reduced U.S. dependence on imports from 60% in 2005 to 30% in 2014. Over the same period, world oil prices doubled and have remained near $100 per barrel since 2008. Recent econometric evidence suggests that world oil supply and demand have become less sensitive to the price of oil, enhancing the market power of oil exporting nations. This paper reassesses the current and future importance of oil dependence in light of these recent developments. Taking uncertainty into account, simulations of possible future oil market conditions to 2040 indicate that the costs of oil dependence are likely to increase in constant dollars but decrease relative to U.S. gross domestic product.

Scenarios of the transition to electric drive passenger cars and light trucks are created using the same model, technology and market behavior assumptions used in the recent National Research Council study, Transitions to Alternative Vehicles and Fuels. The transition is assumed to begin in California and the other U.S. states that have adopted California's Zero Emission Vehicle (ZEV) requirements. Five years after the ZEV standards take effect in 2015, the rest of the U.S. adopts polices strongly supporting the transition. After roughly a decade of net costs, market adoption of electric drive vehicles becomes self-sustaining. In the long run, the model implies that social benefits exceed excess costs by approximately an order of magnitude. Analysis of major energy transitions is characterized by deep uncertainty due to the long time constants for energy system change, the unpredictability of technological change and government policies, inadequate understanding of market processes, and the many important positive feedback mechanisms that create tipping points. (C) 2013 Elsevier Ltd. All rights reserved.

Together with policies already in place, a transition to zero emission vehicles (ZEVs) could almost eliminate petroleum use by light-duty vehicles and meet U.S. CO2 emission reduction goals by 2050. However, such a transition poses new challenges for public policy because of the time required, deep uncertainty, strong positive feedback effects, and regional and international interdependencies. An appropriate framework for evaluating public policy is cost/benefit analysis of alternative futures incorporating these elements. Using the same computer model used in a recent National Research Council study, the types, timing and intensity of public policy interventions likely to be necessary to accomplish a transition to electric drive vehicles in the U.S. are investigated, with special attention to the role of California's ZEV mandates. Strong, temporary policies addressing the coevolution of the vehicle and fuels markets appear necessary. Because uncertainty about the transition is profound, policies must adapt as learning reduces uncertainty.