Reforming the Automobile Fuel Economy Standards Program

Amory B. Lovins, CEO of RMI, submits comments to NHTSA challenging the technical basis of its proposed rulemaking on automobile fuel economy standards. He argues that NHTSA incorrectly relies on retrospective correlations between vehicle weight and safety, which fail to account for modern materials like advanced polymer composites and high-strength steels. Lovins asserts that these materials can create vehicles that are simultaneously large, lightweight, and safe, thereby eliminating the perceived tradeoff between fuel economy and crashworthiness. He recommends that CAFE standards be performance-based, technology-forcing, and based on size metrics rather than mass to avoid incentivizing a 'mass arms race' and to maintain the global competitiveness of U.S. automakers.

• NHTSA's reliance on historic correlations between vehicle weight and crash risk is technically flawed because these retrospective data lack predictive validity for future vehicles built with different materials and designs.
• Vehicle size, rather than mass, is the most critical safety parameter that does not conflict with fuel efficiency, as increased crush length absorbs energy without increasing the danger posed to other vehicles.
• Advanced polymer composites, particularly those reinforced with carbon fiber, can absorb significantly more energy per kilogram than steel, allowing ultralight vehicles to offset their mass disadvantage in collisions.
• The 'Revolution' concept car demonstrates that a midsize crossover can be designed to be 52% lighter than comparable vehicles while maintaining high safety standards and achieving high fuel efficiency (up to 114 adjusted-EPA-mpg-equivalent with a fuel cell).
• The 2001 NAS/NRC study used by NHTSA is criticized for underestimating market dynamism and ignoring the feasibility of simultaneous lightweighting and safety improvements.
• Proposed CAFE modifications should be performance-based and neutral toward vehicle mass to avoid encouraging an increase in vehicle weight, which harms safety and fuel economy.
• The distinction between cars and light trucks in CAFE standards is inappropriate and should be abolished, as the same technical opportunities for efficiency apply to both.

APA

Lovins, A. B. (2004). Reforming the Automobile Fuel Economy Standards Program. RMI. https://rmi.org/app/uploads/2017/05/RMI_Document_Repository_Public-Reprts_E04-10_FuelEconStand.pdf

Chicago

Lovins, Amory B. Reforming the Automobile Fuel Economy Standards Program. RMI, 2004. https://rmi.org/app/uploads/2017/05/RMI_Document_Repository_Public-Reprts_E04-10_FuelEconStand.pdf.

Wikipedia

{{cite press release |last1=Lovins |first1=Amory B. |title=Reforming the Automobile Fuel Economy Standards Program |publisher=RMI |date=26 April 2004 |url=https://rmi.org/app/uploads/2017/05/RMI_Document_Repository_Public-Reprts_E04-10_FuelEconStand.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@misc{lovins2004reforming, author = {Lovins, Amory B.}, title = {{Reforming the Automobile Fuel Economy Standards Program}}, publisher = {RMI}, year = {2004}, month = apr, url = {https://rmi.org/app/uploads/2017/05/RMI_Document_Repository_Public-Reprts_E04-10_FuelEconStand.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }