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U.S. Department of Transportation **Research and Innovative Technology**  **Administration** Volpe National Transportation Systems Center Ju ly 25 , 2011 MEMORANDUM SUBJECT: Ex parte m eeting with FROM: Maurice Hicks , NHTSA TO: Docket No. NHTSAThis memorandum documents a meeting held on regarding the proposed fuel efficiency and greenhouse gas standards for medium vehicles and engines for model years 2014 EXA : Stephen Remondi, Doug Hatfield, and Alex Alajbegovic EPA: Byron Bunker, Cle Jackson, Arvon Mitcham, Chien Sze, Cheryl Bynum, Rich Zhang, Sam Waltzer, and Angela Cullen NHTSA/ DOT : Angel Jackson and Maurice Hicks The following topics were discussed during the meeting: Background EXA requested a meeting with EPA and NHTSA to discuss testing approaches for determining the aerodynamics drag coefficient for heavy duty tractors. EXA stated that CFD has significant benefits over wind not being limited to a 0 degree headwind (Zero Yaw), non closed source environment. EXA has validated CFD mo laboratories used by industry. During the meeting EXA and the agencies discussed EXA’s models and CFD modeling . EXA asked the agencies to: a) Re - run GEM model results for baselines used by EPA b) Consider best practices for aerodynamic simulation considering all the tools currently available in the market. Volpe National Transportation Systems Center

eeting with EXA Corporation , NHTSA

- 2010 - 0079 This memorandum documents a meeting held on November 30 , 2010 between EXA, EPA regarding the proposed fuel efficiency and greenhouse gas standards for medium - and heavy vehicles and engines for model years 2014 - 2018. The attendees included: Stephen Remondi, Doug Hatfield, and Alex Alajbegovic Byron Bunker, Cle Jackson, Arvon Mitcham, Chien Sze, Cheryl Bynum, Rich Zhang, Sam Waltzer, and Maurice Hicks The following topics were discussed during the meeting: EXA requested a meeting with EPA and NHTSA to discuss testing approaches for determining the

coefficient for heavy duty tractors. CFD has significant benefits over wind -tunnel testing. Modeling has superior benefits by not being limited to a 0 degree headwind (Zero Yaw), non - moving wheels (or road conditions) and a closed source environment. EXA has validated CFD mo dels to several full scale wind tunnels test During the meeting EXA and the agencies discussed the availability of run GEM model results for baselines used by EPA with CFD results for aerodynamic inputs. best practices for aerodynamic simulation considering all the tools currently available 55 Broadway Cambridge, MA 02142

, EPA, and DOT and heavy - duty Byron Bunker, Cle Jackson, Arvon Mitcham, Chien Sze, Cheryl Bynum, Rich Zhang, Sam Waltzer, and

EXA requested a meeting with EPA and NHTSA to discuss testing approaches for determining the tunnel testing. Modeling has superior benefits by moving wheels (or road conditions) and a dels to several full scale wind tunnels test the availability of with CFD results for aerodynamic inputs. best practices for aerodynamic simulation considering all the tools currently available2 c) Consider best practices or approaches to moving models to public domain for validation of

model resu lts by industry. The agencies agreed to consider the above requests.