**UNITED STATES ENVIRONMENTAL PROTECTION AGENCY** NATIONAL VEHICLE AND FUEL EMISSIONS LABORATORY

2000 TRAVERWOOD ROAD ANN ARBOR, MI 48105
- 2498

OFFICE OF AIR AND RADIATION July 29 , 2011 MEMORANDUM SUBJECT: Meeting with PACCAR FROM: Angela Cullen TO: Docket EPA
- HQ
- OAR
- 2010
- 0162 This memorandum documents a meeting held on May 3, 2011 b etween PACCAR and EPA. Paccar requested a meeting to discuss the tractor aerodynamic drag certification testing method. In the NPRM, the agencies proposed that tractor manufacturers use a two part screening approach for determining the aerodyn amic inputs to the GEM. The first part of the proposed evaluation approach uses a bin structure characterizing the expected aerodynamic performance of tractors based on definable vehicle attributes. The first part would require manufacturers to assign each vehicle aerodynamic configuration to one of five aerodyn amic bins. For each bin, EPA and NHTSA have alread y defined a nominal Cd. The five bi ns are “classic,” which incorporate few if an y aerodynamic features; “conventional” which represent the average new tractor sold today ; “SmartWay” which have added components to reduce drag: “Advanced SmartWay ,” which have underbod y airflow treatments, do wn exhaust, and other features, and “Advanced SmartWay

I I which incorporates technologies that are still in the prototy pe stage such as advanced gap closing. The second proposed evaluation uses aerodynamic testing. Manufacturers would be required to comp are their test results with the bin Cds. I f their test data shows a better or worse result than the Cd assignment, they would be required to certify to the correct bin. The agencies expressed an interested in working with the regulated industry to develop a primary

test approach. The agencies proposed to allow Cd assessments with vehicle coast down testing, wind tunnel testing, computational fluid dy namics, and constant speed tests combined with good engineering judgment. There are two sub

- categories for class 7 trucks: 1) low/mid roof day

cabs; and 2) high roof day cabs. There are five sub

- categories for class 8 trucks: 1) low/mid roof day cabs; 2) high roof day

cabs; 3) low roof sleeper cabs; 4) mid roof sleeper cabs; and 5) high roof sleeper cabs.2

P accar asked that in addition to requests made b y EMA/TMA to improve the aerod yn amic drag coefficient test method and which are described in a memo to the docket several additional items be considered b y the agencies in establishing the reference test metho d. Paccar stated the proposed changes would improve repeatability and accuracy

and reduce the test burden on regulated entities. They

requested the following: o Cl osed road for coast down testing ; o S tandardize d trailer gap at the centerline of the vehicl e ; o Specif ied height of the trailer at front and back ; o Specified tractor tires ( including mileage and other important parameters); o The agencies i dentify and define parameters that have not been defined (such as data smoothing, frequency of calculation, et c.) ; o Recommend limiting grade to 0.1% (vs. 0.5% currently) because the gravitational effect of a 68,000 pound vehicle is a large contributing factor to low speed road load
.