From: david.kayes@daimler.com

To: Byron Bunker/AA/USEPA/US@EPA

Cc: donald.keski-hynnila@daimler.com, brian.burton@daimler.com, francis.seymour_jr@daimler.com

Date: 07/14/2011 07:49 PM

Subject: Further issues re. the HDV GHG regs

Byron,

A few more quick issues that I want to follow up on, after our discussion a few weeks ago:

A very important issue for us is changing the date of manufacture definition. I am not sure that we 

made this sufficiently clear during our discussions before. Our VIN, which includes a model year 

designation, is stamped on frame rails in advance of a vehicle build. We cannot change that VIN 

without great difficulty once the vehicle begins its build process. The EPA's proposed build date 

(and in turn, model year designation) would depend on the last date of manufacturing, which can 

vary significantly (e.g., if one single part is out of stock, such that a vehicle goes into "off-line"). 

The EPA proposed limiting this just to manufacturing at the main production facility, but that does 

not solve the problem. Rather, the agency would put us in the difficult position of having to 

restamp frame rails every time a part shortage pushes a vehicle from one year's build period to 

the next, since those vehicles are still at the main production facility. Moreover, the EPA's 

proposed requirement would potentially lead to different VINs for NHTSA as for the EPA. (Recall 

that NHTSA does not have such a build completion provision.) To resolve these issues, I 

recommend that the EPA use a build date specification that is more simple to nail down, like the 

engine-in-chassis date or the date on which rails start down the vehicle manufacturer's assembly 

line.

In June the EPA suggested adding a requirement for use of a wind tunnel that the wind tunnel meet 

SAE J1252 specifications. This is problematic for Daimler and perhaps for every vehicle 

manufacturer in the US because of the blockage ratio requirement. Section 5.2 of 1252 limits 

tunnels to a blockage ratio of 1/20 at 0 degrees yaw and 0.3 at max yaw. With Daimler's 

contoured wind tunnel, this is not possible, so we would be unable to use otherwise good data 

from this wind tunnel. With the NRC wind tunnel and a full sized trailer, I am not sure that the 

yawed blockage ratio can be met. (Perhaps it can, but I think not, just because so much side 

area becomes exposed. I bet Arvon or Prashanth know better than me.) In short, I request at 

least the possibility that Daimler be able to certify our non-1252 tunnel so that we can use data 

from it.

Lastly, a new issue that just came to my attention: some fleets (like Waste Management) and natural 

gas engine manufacturers (like Cummins Westport) suggested in their January comments to the 

EPA that natural gas vehicles should be eligible for a credit multiplier like the 6.67x multiplier 

available for LDVs using natural gas, an option presented but dropped in the NPRM. (75 FR 

74198.) I know that HDEs will benefit from the low CO2 emissions of natural gas. But HDVs 

could definitely benefit from a credit for natural gas use, like LDVs do. I do not know what is the 

correct multiplier, 6.67 or something else, but advanced technologies may get a 1.5x multiplier. 

Perhaps natural gas vehicles should too, since NGVs are quite expensive, like hybrids. Or, 

perhaps the natural gas engines should get credits with a 1.5x multiplier that are fungible like 

advanced technology credits.

Regards,

Dave

-------------------------

David Kayes

Compliance and Regulatory Affairs --- Environmental Compliance

Daimler Trucks

(503) 745-9162 Office
(503) 265-9838 Mobile

David.Kayes@Daimler.com

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