*** E.O. 12866 Review

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## EPA and NHTSA Response to **June 17**  **, 2015 Verbal**  **Interagency Comments on Preamble Section IX Rebound**  **-**

**HDV Phase 2 NPRM** Agencies	Responses : In	response	to	E.O	12866	comments,	the	agenci es	will	incorporate the	text	changes	which	are	shown	in	red	type,	below. **(3) How the Agencies**  **Estimated the HDV Rebound Effect for this Proposal**  (a ) Values Used in the Phase 1 Analysis At the time the agencies conducted their anal ys is of the Phase 1 fuel efficien cy and GHG emissions standards, the only evidence on the HDV rebound effect were the previousl y described studies from CSIand the Volpe Center. 1 On the basis of this evidence and the agencies’ judgement , the agencies chose rebound effects of 15 percent for vocational vehicles and 5 percent for combination tractors, both of which were toward the lower end of the range of values from these studies. The agencies found no evidence on the rebound effect for HD pickup trucks and vans, but concluded it would be inappropriate to use the values selected for vocational vehicles or combination tractors for those vehicles. Because the usage patterns of HD pickup trucks and vans can more closely resemble those of large light
- dut y vehicles, the agencies used our judgement to select the 10 percent rebound effect we had employed in our most recent light
duty rulemaking to anal yze the Phase 1 standards for 2b/3 vehicles. (b ) How the Agencies Analyzed VMT Rebound in this Prop osal After considering the new evidence that has become available since the HD Phase 1 final rule, the agencies elected to continue using the rebound effect estimates we used previousl y in

1 The Gately study was also available, however, the agencies were not aware of the work at the time.*** E.O. 12866 Review

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the HD Phase 1 rule in our anal ys is of Phase 2 proposed standards. In arriving at this decision, the agencies considered the shortcomings and limitations of the newl y - available studies described previously , particularly the limited applicability

of the two published studies using data from European nations to the U.S. co ntext. After weighing these attributes of the more recent studies, the agencies concluded that we had insufficient evidence to justify revising the rebound effect values that were used in the Phase 1 anal ys is. In our assessment, we do not differentiate be tween short
- run and long
- run rebound effects, although these effects may differ. The vocational and combination truck estimates are based on the Volpe Center anal ys is presented in the HD Phase 1 rule and the case study from CSI . As with the HD Phase 1 ru le, we did not find any literature specifically

examining the HD pickup and truck sector. Since these vehicles are used for very different purposes than combination tractors and vocational vehicles, and they are more similar in use to large light
- duty veh icles, we have chosen the light
- dut y rebound effect of 10 percent used in the final rule establishing fuel economy and GHG standards for MYs 2017
- 2025 light
- duty vehicles in our anal ys is of HD pickup trucks and vans. While for this proposal, the agencies have selected to use these rebound effect values of 5% for combination tractors, 10% for heav y dut y pickup trucks and vans and 15% for vocational vehicles , we acknowledge the literature shows a wide range of rebound effect estimates. Therefore, we will re view and consider revising these estimates in the final rule, taking into consideration all available data and anal ys is, including submissions from public commenters and new research on the rebound effect.

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