Vehicle fleet turnover and the future of fuel economy

David R. Keith, Samantha Houston, Sergey Naumov

Research output: Contribution to journalReview articlepeer-review

36 Scopus citations


The real-world impacts of the Trump administration's effort to roll back the Corporate Average Fuel Economy (CAFE) standards for new light-duty vehicles are not obvious, because new vehicles are highly durable and remain in the on-road fleet for many years. We demonstrate that freezing CAFE between 2020-2026, one of the proposals circulated by the Trump administration, will increase fleet fuel consumption and greenhouse gas emissions until 2040 and beyond, because relatively less-efficient vehicles sold during this time would remain in use for potentially decades. We argue for stringent fuel-economy standards for new vehicles, and for placing greater emphasis on the retirement and disposal of the oldest and most inefficient vehicles on our roads. These steps will help to build a fleet that is efficient, low-emission, and adaptable as the automotive industry enters a period of unprecedented technological change.

Original languageEnglish (US)
Article number021001
JournalEnvironmental Research Letters
Issue number2
StatePublished - Feb 15 2019

All Science Journal Classification (ASJC) codes

  • Renewable Energy, Sustainability and the Environment
  • General Environmental Science
  • Public Health, Environmental and Occupational Health


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