Good afternoon. I am Debbie Gordon, Executive Director of Regulatory Issues and Hybrid 

Programs for Allison Transmission. Allison Transmission is the world’s largest manufacturer 

of fully automatic transmissions for medium- and heavy-duty commercial vehicles and is a 

leader in hybrid-propulsion systems for city buses. Allison transmissions are used in a variety 

of applications including refuse, construction, fire, pick-up and delivery, distribution, bus, 

motorhomes, defense and energy. Our global headquarters are in Indianapolis, Indiana and I am 

proud to say that we are celebrating our centennial year. 

Over the last six years, Allison has engaged with EPA and NHTSA regarding the two agencies’ 

efforts to address the greenhouse gas emissions and fuel efficiency of medium and heavy-duty 

vehicles. During this time, we have always been afforded the opportunity to directly engage 

with EPA and NHTSA technical staff and management.

In addition, Allison has supported efforts by EPA and NHTSA to test transmissions and 

increase the base of knowledge that both agencies have with regard to the effect of transmission 

systems on greenhouse gas emissions and fuel efficiency. Our overriding concern has been that 

any regulations that affect transmissions and our customers accurately reflect the capabilities of 

fully automatic transmission systems and hybrid systems. We have also emphasized the 

importance of assessing the relative performance of vehicles and transmission systems with 

respect to the real world operating conditions of commercial vehicles.

It is a considerable understatement to note that the proposed Phase 2 rule is a complicated 

rulemaking. We are still in the process of reviewing the rule and its supporting technical 

analysis. But one thing is abundantly clear: the Greenhouse Gas Emission Model (or “GEM”) 

plays a crucial role in Phase 2 regulations. GEM, literally, determines how you comply. 

Allison fully supports EPA’s ongoing efforts to make GEM more accurate and more 

representative of real world vehicles. We also support the use of GEM as the primary 

certification methodology -- but we have some significant concerns with the quality of GEM 

software and EPA technical and policy choices regarding GEM.

First, GEM does not run well. When GEM was delivered, there were missing files and then 

when we got it to run, there were a number of coding errors identified. Secondly, the model 

produces unrealistic operation over the duty cycles. The lockup shift strategy and the neutral 

loading and automatic neutral functionality are inappropriate. And, finally, there are major 

deficiencies in the base control algorithms. Some production vehicle configurations would not 

shift out of first range. Others do not downshift at highway speeds when a load is encountered. 

We have also seen the GEM controller release lockup at highway speeds which would never 

happen.

These examples do not reflect how fully automatic transmissions operate. And flaws in GEM 

will directly translate into flaws in the final rule. In short, GEM is not ready for “prime time” 

as the certification tool. 

Allison Transmission Public Comments EPA and NHTSA Public Hearing August 6, 2015 Chicago, IL
Given this situation, we believe that EPA and NHTSA mustbe mindful of the procedural 

requirements of the Clean Air Act and the Administrative Procedure Act. Adequate 

opportunity for comment must be provided, especially with regard to a central element of the 

rulemaking, such as GEM. 

With regard to GEM, the devil really is in the details. It is impossible to understand and 

reasonably project the effect of any final rule without understanding precisely how GEM will 

operate, what it will measure and how it will assess different systems. This is especially true in 

the vocational vehicle market where there are hundreds of different vehicle types and is

amplified where, as here, EPA and NHTSA intend to decrease greenhouse gases and improve

fuel efficiency through the deployment of new technology.

When GEM executable files will not run; when other errors are found in GEM, when delays 

occur in making changes to the model -- the very process of the public comment period is called 

into question. Without refinement, GEM results could be considered arbitrary.

To be clear, we intend our comments not as a reflection of the hard work of EPA and NHTSA 

or their staff. Instead, our criticism is a reflection of the extremely complicated nature of the 

proposed rule and its heavy reliance on computer modeling. 

We believe that there are several ways EPA can address this situation. One avenue would be to 

extend the comment period to allow a sufficient time to resolve GEM “bugs” and to allow the 

public sufficient time to run the model and fully understand its implications. In our view, there 

is no downside to this option since there is no legal deadline for a final rule. Another possible 

avenue would be to reopen the public comment period when GEM is further developed. Other 

administrative avenues are potentially available, including issuing a Notice of Data Availability 

with an opportunity for comment.

Allison Transmission is looking forward to continuing work with EPA and NHTSA, but we ask 

now, at this stage, that the agencies recognize GEM needs further refinement to allow for public 

comment and that, overall, the operation of the model must be improved. We urge EPA and 

NHTSA to seriously consider this matter prior to the announced deadline for the submission of 

comments.

Allison Transmission Public Comments EPA and NHTSA Public Hearing August 6, 2015 Chicago, IL