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Corporate Average Fuel Economy

Light Duty CAFE Midterm Evaluation

Model Years 2022-2025


On July 18, 2016, NHTSA, EPA, and CARB completed the first step in the mid-term evaluation process for CAFE and GHG emissions standards for model years 2022-2025 by issuing a Draft Technical Assessment Report (TAR).The Draft TAR evaluates fuel economy improvements made in response to CAFE and GHG emissions standards so far, and how auto manufacturers could improve their fleets to meet more stringent standards in the future. The Draft TAR is the first step in the mid-term evaluation process, and stakeholder input on the analysis and findings is crucial to NHTSA’s upcoming rulemaking to set CAFE standards for MYs 2022-2025, which will be coordinated with EPA’s Proposed and Final Determinations on the GHG emissions standards for those same model years.


Draft Technical Assessment Report (TAR)

The first step in the process is the issuance of the Draft TAR for public comment. The Draft TAR is a technical report, not a decision document, and examines a wide range of factors relevant to the 2022-2025 standards. Public input on the Draft TAR, along with any new data and information, will inform the next step – NHTSA's Notice of Proposed Rulemaking and EPA's Proposed Determination.

NHTSA Notice of Proposed Rulemaking (NPRM) / EPA Proposed Determination (or NPRM)

NHTSA is required by Congress to conduct a comprehensive new rulemaking in order to establish CAFE standards for MYs 2022–2025. The next step in the process after the Draft TAR is to issue a Notice of Proposed Rulemaking (NPRM) in conjunction with EPA's Proposed Determination or NPRM. The NHTSA NPRM will go through the full public comment process and comply with all established Federal rulemaking requirements.

EPA's Proposed Determination will be the EPA Administrator's proposal on whether the 2022-2025 standards are appropriate under section 202(a) of the Clean Air Act. The Proposed Determination will be available for public comment, as required by EPA's regulations. If the Administrator's proposal is that the standards should change (either more or less stringent), then EPA will work with NHTSA to issue a joint Notice of Proposed Rulemaking, which will include both NHTSA's proposed CAFE standards and EPA's proposed GHG standards.

Public input on the Notice of Proposed Rulemaking and EPA's Proposed Determination, as well as new data and information available, will inform the next step - NHTSA's Final Rule and EPA's Final Determination (or Final Rule).

NHTSA Final Rule / EPA Final Determination (or Final Rule)

Following a full NPRM public comment period, NHTSA will address comments and issue a Final Rule on CAFE standards for MYs 2022-2025 in conjunction with EPA's Final Determination or Final Rule. EPA’s Final Determination as to whether the standards should change must be made by April 1, 2018. If the EPA determination is that the standards will not change, NHTSA will issue its CAFE final rule concurrently with the EPA Final Determination (77 FR 62652, October 15, 2012). If the EPA determination is that the standards will change, the agencies will issue a joint final rule, which could be by April 2018 or a later date. At the very latest, the agencies will complete the final rule in sufficient time to issue final standards for MY 2022-2025 with at least 18 months lead time, but additional lead time may be provided (77 FR 62785, October 15, 2012).

Technical Projects

NHTSA Technical Projects to Inform the Midterm Evaluation and CAFE Rulemaking

NHTSA has sponsored and will continue to sponsor new studies and research to inform the mid-term evaluation, NHTSA's CAFE rulemaking, and EPA's potential GHG emissions rulemaking. The technical projects are summarized and linked below. In establishing standards, the agencies will consider all available data, studies, and information objectively, without regard to whether they were sponsored by the agencies.

Cost, Effectiveness and Deployment of Fuel Economy Technologies for Light-Duty Vehicles

(613 pp, 15MB, 2015, National Academy of Sciences). Committee on the Assessment of Technologies for Improving Fuel Economy of Light-Duty Vehicles, Phase 2; Board on Energy and Environmental Systems; Division on Engineering and Physical Sciences; National Research Council. The National Academies Press, Washington, DC.

Argonne National Laboratory (ANL) large-scale simulation using Argonne's Autonomie Vehicle simulation tool to estimate the effects of combinations of technologies on fuel economy. Simulation of all feasible technology combinations is yielding databases that are flexible, account for all technology interactions, and can be fed directly into the CAFE model, which NHTSA uses for fleet-level analysis. (click to access sub-bullets)

Simulation Inputs and Results for Draft TAR CAFE analysis:

a) Process Description and Modeling Assumptions Report. Argonne report describing vehicle simulation process, as well as resulting database structure and design for use in the CAFE model.
b) IAV Engine performance map assumption, development process and results. [pdf file]
c) Engine Maps. Detailed results of engine simulations performed by IAV Automotive Engineering using GT-POWER to estimate fuel consumption as a function of engine speed and torque output.
d) Vehicle Model Assumptions. Files containing the main model assumptions including vehicle, engine and transmission characteristics for 5 passenger car and light truck classes.
e) Effectiveness Databases. Files containing technology combination effectiveness results from Autonomie simulations for 5 passenger vehicle car and light truck vehicle classes. [61MB zip]
f) Data Dictionary. Dictionary of fields and units in simulation database.

Related Argonne National Laboratory Publications

a) Kim, N., Shidore, N., Rousseau, A. "Sizing Algorithm Validation for Several Vehicle Powertrains" [PowerPoint Slides]
b) Rousseau, A., Shidore, N., Karbowski, P., Sharer, P. "Autonomie Vehicle Validation Summary" [PowerPoint Slides]
c) Islam, E., Moawad, A., Rousseau, A. (July 25th, 2015) "Fuel Consumption Improvement Study over combinations of technologies [Rev. 2] VOLPE vs. Autonomie (ANL)" Presentation for DOT/VOLPE
d) Moawad, A., Rousseau, A. (June 2, 2015) "Engine Parametric Study /-10kW range with a step of 1kW" Presentation for DOT/VOLPE
e) Moawad, A., Balaprakash, P., Rousseau, A. EVS28 Conference "Novel Large Scale Simulation Process to Support DOT's CAFE Modeling System." KINTEX, Korea, May 3-6, 2015 [Paper] [Presentation]
f) Kim, N., Shidore, N., Rousseau, A. "Vehicle Modeling for use in the CAFE model process description and modeling assumptions"

Mass reduction study on midsize passenger car using 2011MY Honda Accord and mass reduction study on full size pickup truck using 2014MY Chevy Silverado

a) Mass reduction of midsize passenger car

b) Mass reduction feasibility and cost study of full-size pickup (2014 Silverado)

  • Draft Report and models
  • Peer review report and response – forthcoming

The crash database was updated to the model years from 2003 to 2010

The approach includes estimating the real-world level of safety in a vehicle for its own occupants (self-protection) and for the occupants in vehicles with which it collides (partner protection)

Methodology for evaluating fleet protection of new vehicle designs: Application to lightweight vehicle designs (Report No. DOT HS 812 051A)

Assessing vehicle mass and size trends and potential safety effects

  • Construct a new reference fleet using an updated baseline fleet and updated market forecast
  • Acquiring a market forecast to be used in forecasting future production volumes

  • DOT (June 23, 2014). National Research Council Assessment of Technologies for Improving Fuel Economy of Light-Duty Vehicles – Phase 2, "NHTSA's Recent Activities on Light-Duty Fuel Economy." Meeting Location: Keck Center, Washington DC.
  • DOT (February 27, 2013). National Research Council Assessment of Technologies for Improving Fuel Economy of Light-Duty Vehicles – Phase 2, "Meeting on Volpe Model and Other CAFE Issues." Meeting Location: Volpe National Transportation Systems Center, Cambridge, MA.