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The Union of Concerned Scientists' 2010 Automaker Rankings evaluate eight major car companies using government data from model year 2008. Honda is ranked as the greenest automaker, while Chrysler is identified as the most polluting for the fourth time in ten years. The assessment emphasizes that overall environmental performance depends on cleaning up entire fleets, including high-volume sellers, rather than relying on a few niche green models.

The document argues that implementing fuel-efficiency standards and technologies for medium- and heavy-duty trucks in the U.S. would generate significant job growth, increase GDP, and reduce greenhouse gas emissions. It highlights that while these vehicles represent only 4% of U.S. highway vehicles, they consume over 20% of fuel, and that widespread adoption of efficiency technologies could save 100 billion gallons of fuel by 2030.

The report argues that improving the fuel economy of medium- and heavy-duty trucks through advanced technologies would create significant net job growth, increase GDP, and reduce global warming emissions, provided that policy interventions overcome existing market barriers.

The document argues that improving the fuel economy of medium- and heavy-duty trucks in the U.S. would create significant job growth, increase GDP, and reduce greenhouse gas emissions, provided that market barriers are overcome through performance standards and incentives.

The document outlines strategies to maximize vehicle fuel economy, categorizing them into vehicle maintenance, driving behavior, and systemic transportation changes. It highlights that proper maintenance, such as using low rolling resistance tires and reducing vehicle weight, can improve mileage. Driving habits, specifically reducing highway speeds and avoiding idling, are identified as key ways to cut fuel use. Finally, it advocates for a transition toward fuel-efficient vehicles, mass transit, and policies that reduce dependence on oil.

The report assesses the potential for reducing greenhouse gas (GHG) emissions, NOx, and fuel consumption in California's heavy-duty truck fleet through retrofit technologies. It evaluates six technology packages across different vehicle types and duty cycles, concluding that a combination of high-technology retrofits for new vehicles and moderate-technology retrofits for in-use vehicles is the most cost-effective strategy. The analysis suggests that focusing on tractor-trailers and straight trucks over 14,000 pounds could reduce state heavy-duty fleet GHG emissions by 14.9 to 22.2 million metric tons of CO2-equivalent between 2010 and 2020.

The guide highlights that Americans' per capita emissions are 21 tons, four times the global average. It argues that while system-wide change is necessary, individual actions—such as improving vehicle fuel economy, sealing home air leaks, reducing beef consumption, and using LED bulbs—can significantly lower emissions and save money. It also encourages political advocacy and public awareness to drive larger systemic shifts, such as the potential closure of 200 coal plants if all Americans reduced emissions by 20 percent.

The document examines the relationship between vehicle weight, fuel efficiency, and safety. It argues that lightweighting can significantly reduce global greenhouse gas emissions—potentially by up to 11% if combined with plug-in hybrid electric vehicles (PHEVs) and a clean grid—without compromising occupant safety. The author contends that vehicle size and design, rather than mass, are the primary drivers of crashworthiness. The paper reviews statistical literature to debunk the 'weight confers safety' argument and provides examples of aluminum, high-strength steel, and carbon fiber composites being used in safe, lightweight vehicles.

The Vacation Traveler Carbon Guide ranks transportation options by carbon emissions for solo travelers, pairs, and families of four across distances of 100, 500, and 1,000+ miles. Motor coaches are consistently ranked as the best option across all categories, while first-class flights and SUVs generally represent the worst options, depending on the distance and group size.

The Union of Concerned Scientists' 2007 report ranks eight major automakers on their environmental impact, focusing on smog and global warming pollutants. Honda is named the 'Greenest Automaker' for the fourth consecutive time, though Toyota has closed the gap significantly due to hybrid technology and consistent performance across all vehicle classes. The report highlights a stark contrast between the top performers and the 'Big Three' (Ford, GM, and DaimlerChrysler), with DaimlerChrysler ranking as the dirtiest. Key findings indicate that while smog emissions have improved due to tighter regulations, progress on global warming emissions has been minimal since 1998. The analysis also critiques the use of flexible-fuel vehicles (FFVs) as a regulatory loophole that increases overall emissions and notes that diesel vehicles reduce global warming pollution but significantly increase smog.

The Union of Concerned Scientists' 2007 rankings identify Honda as the 'Greenest Automaker' and DaimlerChrysler as the most polluting based on 2005 emissions data. The analysis evaluates eight companies representing 96 percent of the U.S. vehicle market, using a 50/50 weighting of smog-forming pollutants (NOx and NMOG) and global warming pollutants (CO2-equivalent). While Honda and Toyota lead in consistency across vehicle classes, the report notes that conventional technologies could reduce global warming emissions by 40 percent, and hybrids could offer further reductions.

The report finds that achieving a 35 mpg fleetwide average by 2018 would create 241,000 net new jobs in the U.S. by 2020, save consumers $37 billion in net costs, and reduce national oil use by 1.6 million barrels per day. Environmental benefits include a reduction of 260 to 264 million metric tons of carbon dioxide-equivalent emissions by 2020. Job growth is projected across most sectors, particularly services and retail, while the oil industry would see a decline. California is projected to experience the highest job growth and consumer savings.

The report ranks the 'Big Six' automakers—Honda, Nissan, Toyota, Ford, DaimlerChrysler, and General Motors—on their environmental performance, focusing on smog-forming and heat-trapping emissions. Honda consistently ranks as the cleanest, while General Motors has fallen to the bottom. The analysis highlights a trend where smog-forming pollution is improving due to regulation, but heat-trapping emissions remain stagnant. It specifically criticizes the use of regulatory loopholes, such as Flex-Fuel Vehicle (FFV) credits, which allow companies to artificially inflate fuel economy figures.

The report compares conventional, advanced, and hybrid-electric diesel and gasoline vehicles across five passenger vehicle classes. It finds that while diesel engines offer higher inherent fuel economy, they are less cost-effective than improved gasoline vehicles for reducing oil use and heat-trapping gases due to higher up-front costs and the higher petroleum intensity of diesel fuel. The report also highlights significant public health concerns, noting that diesel vehicles historically emit substantially more toxic soot and nitrogen oxides than gasoline vehicles. While new federal Tier 2 standards aim to close this gap, the report argues that diesel's future depends on overcoming technical challenges in emissions control and ensuring real-world performance matches certification. It recommends maintaining strict emissions standards, modifying CAFE to use energy-equivalent measures, and expanding inspection and maintenance programs to include diesel vehicles.

The Union of Concerned Scientists report 'A Blueprint for Saving Lives, Money, and Gasoline' analyzes the safety and environmental shortcomings of SUVs and light trucks in the United States. It highlights high rollover fatality rates, significant air pollution, and poor fuel economy compared to passenger cars. To demonstrate potential improvements, the authors propose two model vehicles—the UCS Guardian and the UCS Guardian XSE—which utilize existing technologies such as unibody construction, advanced engines, and electronic stability control to increase fuel efficiency and reduce fatalities without sacrificing vehicle size or performance.

The report argues that hybrid electric vehicles (HEVs) can bridge the gap between current conventional vehicle technology and the long-term adoption of hydrogen fuel cells. It categorizes hybrids into mild, full, and plug-in types based on technological steps like regenerative braking and electric-only drive. Modeling suggests a passenger fleet using advanced full hybrids could reach an average of 60 mpg, significantly reducing oil consumption and greenhouse gas emissions while remaining cost-effective for consumers over the vehicle's lifetime.

The report evaluates the environmental performance of the 'Big Six' automakers—Honda, Toyota, Nissan, Ford, General Motors, and DaimlerChrysler—using government data on smog-forming pollutants and greenhouse gases. Honda is ranked as the cleanest, while DaimlerChrysler is the dirtiest. The analysis highlights a significant pollution gap between cars and trucks, noting that trucks are permitted to emit more pollutants under current regulations. While smog-forming emissions decreased across the industry due to the National Low Emission Vehicle (LEV) program, global warming gas emissions increased, driven by a shift toward larger, less efficient vehicles. The report argues that voluntary corporate commitments, such as Ford's effort to reduce truck emissions, can improve rankings, but emphasizes that government regulation is necessary for industry-wide progress.

The report argues that the US can significantly reduce its oil consumption and environmental footprint by aggressively raising Corporate Average Fuel Economy (CAFE) standards. It proposes a path to 40 mpg by 2012 and 55 mpg by 2020 using evolutionary conventional technologies and hybrid electric vehicles. The analysis suggests these improvements would save consumers billions of dollars, create over 100,000 automobile industry jobs by 2020, and reduce greenhouse gas emissions by 888 million tons by 2020. Furthermore, the report contends that these fuel savings would far exceed the potential oil supply from the Arctic National Wildlife Refuge and that safety can be maintained or improved through better design and the reduction of weight disparity between light trucks and passenger cars.

The document proposes the "hypercar" concept, which utilizes a recursive "mass decompounding" process to create ultralight vehicles. By combining advanced composites and hybrid-electric drives, the authors argue that cars can achieve significantly higher fuel economy and lower emissions without sacrificing performance or cost. The paper examines the lifecycle benefits of this approach, including reduced embodied energy in manufacturing, lower in-use emissions, and the potential for high-value recycling of polymer composites through processes like low-temperature catalytic pyrolysis.

The paper presents a technical case for 'ultralight hybrid vehicles' (UHVs), asserting that fuel efficiency can be improved 3–4x over conventional cars without compromising marketability. It emphasizes that reducing tractive loads—through mass reduction, aerodynamic optimization, and low-rolling-resistance tires—is the most critical factor in making hybrid drivesystems cost-effective. Using the SIMPLEV model, the author demonstrates a design with a curb mass of 585 kg and a drag coefficient of 0.19 that achieves high fuel economy (up to 115 mpg on highways) and low emissions, while meeting strict performance criteria for acceleration and gradability.