Summary of Interagency Working Comments Received on Draft Rule under EO 12866 Review.  Subject to

Further Policy Review

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Below is a summary of interagency comments received during EO 12866 review of the draft 

proposed rule establishing GHG emissions standards and fuel efficiency standards for medium 

and heavy duty trucks. They are for your consideration and subject to further policy review. 

1) Cost-Benefit Analysis of Alternatives to Proposed Stringency levels 

Multiple commenters continue to request that the agencies conduct cost-benefit analysis of 

alternatives to the proposed stringency levels for all vehicle and engine classes. Similar to the 

8 alternative stringencies analyzed in the light-duty CAFE rule, commenters request that the 

agencies fully discuss these regulatory alternative stringency levels and their estimates of 

costs and benefits in the NPRM and RIA. 

2) Restrictions on flexibilities

Commenters continue to request that the agencies remove restrictions on flexibilities from 

the main proposal. Changing the current proposal should not be difficult or time-consuming. 

Please clarify that averaging, banking, and trading is allowed across vehicle classes and 

engine classes. If the agencies have reasons to believe these restrictions are necessary, then 

they can add discussion of an alternative scenario with these restrictions on flexibilities in 

place. The agencies could seek public comment on whether flexibilities across vehicle 

classes and engines without restrictions should be allowed (under the main proposal) or 

whether the final rule should include restrictions on flexibilities across classes (as an 

alternative to the main proposal). 

3) Alternative compliance fee 

Commenters request that the agencies seek public comment on whether the final rule should 

allow manufacturers to pay a fee if they are unable to comply with the standards. The lightduty rule allows this noncompliance fee and if manufacturers don’t need to use this, then this 

provision will simply not be utilized. Adding language on an alternative compliance fee 

should not be time-consuming or difficult. 

4) Means of Assessing Compliance with Standards: Simulation Model 

Commenters recognize that EPA is proposing to use a new model, recently developed from 

scratch, that has not been published or peer reviewed to assess compliance with proposed 

standards regulating the fuel economy and GHG emissions of heavy duty and medium duty 

vehicles for the very first time. Commenters also note that there is another more fully 

developed model called PSAT/Autonomie which has compliance-aspect functions that have 
Summary of Interagency Working Comments Received on Draft Rule under EO 12866 Review.  Subject to

Further Policy Review

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been validated multiple times over the past 3 years with underlying software that has been in 

existence for over 10 years. Commenters also note that this model does not pose any 

problems regarding proprietary information and that industry is already using it. Are the 

agencies aware of this model’s existence and extensive use by the industry? The agencies 

should include a full discussion of PSAT/Autonomie in the NPRM and seek public 

comment on whether there are benefits to using the PSAT/Autonomie model in the final rule 

instead of TEST. 

Adding this language should not be difficult or time-consuming.

5) “Market Failure” 

Based on agency responses, it is clear that two of the 5 arguments that the agencies use are 

testable hypotheses. Commenters request that the following 3 arguments be completely dropped 

from the NPRM and RIA because they are unfounded and even contradictory to claims made in 

other parts of the NPRM: 

-Reason #1: Trucking companies do not have adequate information about 

technologies available or the fuel efficiency of various trucks. 

-Reason #4: Uncertainty about future cost savings. 

-Reason #5: Adjustment and transaction costs: where new technologies are 

likely to be adopted over time without market intervention. 

For reasons # 2 (split incentives) and #3 (information asymmetry)- please clearly state in the 

NPRM that these are testable hypotheses and the agencies seek comment on whether there is 

any empirical evidence supporting them. 

Making these changes should not be difficult or time-consuming.

6) Alternative Baselines 

Commenters request that the agencies clarify in the NPRM that the assumption that no fuel 

economy improvements will occur absent this rule is not backed by empirical evidence or 

historical data. Commenters request the agencies to seek comment on whether this 

assumption is accurate and whether alternative baseline scenarios that assume greater 

improvements in fuel economy is more appropriate for the final rule. These changes should 

be very easy to make. 

7) Probabilistic Uncertainty Analysis
Summary of Interagency Working Comments Received on Draft Rule under EO 12866 Review.  Subject to

Further Policy Review

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Commenters request that agencies conduct this analysis and include it in the RIA before it is 

published for public comment. The agencies already have experience doing this analysis 

since the light-duty CAFE rule included an uncertainty analysis. 

8) Learning curves

The commenters request that the agencies completely drop all time-based learning curves 

and use only one volume-based learning curve. Commenters request agencies to seek 

comment on whether the volume-based learning curve is accurate and appropriate, 

including whether it leads to underestimation of costs that should be revisited and adjusted 

for the final rule stage. This change should not be very time-consuming. 

9) Welfare Impacts

Similar to NHTSA’s analysis of consumer welfare impacts in the light-duty CAFE rule, 

commenters request that the agencies include 25% and 50% welfare loss scenarios 

offsetting the benefits in this NPRM and RIA. 

10) Treatment of Fuel Savings in RIA and NPRM 

Commenters continue to request that the agencies include fuel savings in the benefits 

category throughout the RIA and NPRM instead of treating them as negative costs. Please 

include this category only in the benefits section because fuel savings are benefits not costs. 

Please make this change throughout the RIA and NPRM. This should be very simple and 

easy to make throughout the documents. 

11) Discussion of interactions with NAFTA.

Commenters request that the agencies include language in the NPRM about possible 

interactions with the NAFTA trucking dispute. Commenters request that the agencies 

include background and context of possible interactions and also state and seek comment 

that this rule could cause truck assembly plants to move to Mexico, to sell trucks to 

Mexican trucking companies operating in the US.