## Summary	of	Interagency	Working	Comments	on	Draft	Language	under	EO

12866	and	EO	13563	Interagency Review.		Subject	to	Further	Policy	Review. **Interagency	Comments	on	U.S. Environmental	Protection	Agency	(EPA)	and	National**  **Highway	Traffic	Safety	Administration	(NHTSA)	draft	proposed	rule	titled,	“Greenhouse	Gas Emissions	and**  **Fuel	Efficiency	Standards	for	Medium -**  **and	Heavy -**  **Duty	Engines	and	Vehicles -**  **Phase	2.”		RIN	2060 -**  **AS16;	RIN	2127 -**  **AL52 General**   Is EPA assuming 100% deployment of the technologies from the Heavy Duty Phase 1 rule? Suggest that the agency take comment on the level of Phase 1 penetration as it does not appear that this has yet to be achieved in the market.  Suggest that EPA take comment on how representative the powertrain calibrations are that are used in GEM that would allow manufacturers the use this data ins tead of steady state fuel maps .  Pg 99 has some language on idle reduction. The commenter requests that the agencies include exemptions for manlifts and cranes. If an automatic engine shutdown is installed, idle reduction rules could potentially lead to safety issues for larger boom equipment as they require the engine to drive the hydraulic system and thus be able to move and raise/lower the manlift and crane.  Pg 51 discusses low rolling resistance tires. The commenter requests an exemption for vehicles that operate primarily off road (such as equipment on Rights of Way (ROW)). The commenting agency has had issues in the past with EPA noise limitations due to some of the additions that were installed on equipment to allow them to operate off road.  For f ederal agency off road vehicle fleets, the ambiguity in the documents due to lack of specifics, especially for technology that isn’t commercially available yet, is concerning as the commenter does not know where any of this equipment would be placed on the vehicles. The commenting agency has vehicle travel height issues even today, and if aerodynamic or other components are added in response to this rule that reduce road clearance under the vehicle, it will have an negative impact due to potential damage t o these systems and subsequent breakdown of off road use vehicles.  The commenter i s concerned that more systems on these trucks means more training for our technician s and more maintenance for the systems in already tight budgets . As we serve the publi c, this will result in higher operational costs for our rate payers.  Expansion of alternative fuel requirements with no commercial infrastructure could result in the agency having to put in place more alternative fuel infrastructure adding to our costs (i. e. our customers' cost) for both the facilities as well as their maintenance, n ot to mention the potential environmental impacts. **Payback Periods** The commenter requests the agencies to consider these technologies that would likely o ffer deeper savings although with higher paybacks.  VTO tractor

- trailer economic models assume a payback curve with a 1

- 2 year preferred payback (~84% of owners at 2 years or less). At 3 years, the adoption rate falls to 22%. However, the commenter’s models do not assume the forcing function of the regulation, instead relying solely on market forces.  For trailers, the ownership period is likely much longer. However, the trailers often are not owned by the same company that purchases/leases the tracto r and pays the fuel bill. And again, the agency analysis has focused solely on market forces without the overlay of regulation.  For vocational vehicles, a six

- year payback may make economic sense because of the longer ownership periods. However, this is a longer period than typical financial planning horizons, particularly for businesses that operate with slim margins.**Certification and Compliance Comments**

 **Data.** Regulations and impact assessments are best supported by sound data and analysis. The age of the Vehicle Inventory and Use Survey (VIUS) data is well known, and there is the general belief that the market has changed considerably since the last survey (13 years ago). There are additional issues with VIUS relating to sampling, selection, and t he reliability of self

- reported data. It is not completely transparent how the forecasts were set beyond use of the MOVES model and DOT CAFE model. It was not clear how second purchasers of vehicles were considered. Additionally, it is not clear what plans there are for in

- use confirmation of regulatory impacts, if any. Assuming VIUS survey updates are not available going forward, the commenter recommends that the agencies clarify the methodology used for sampling, forecasts, and whether pursuing some ty pe of in

- use data collection or survey would have any practical utility.  **GEM.** The improved features and flexibility of t he GEM model are evident, yet the commenter note s that the usefulness of the tool is limited to technologists and suggests the agencies make it more layman friendly. The commenter notes that for customer guidance, the OEM simulation tools for specifying trucks for first

- purchasers will remain more accessible, detailed and accurate for real

world analysis than GEM. For buyers of used truc ks, an online, user

- friendly truck simulation is not currently available.  **Transparency/on -**  **line tool (based on GEM).** We agree that analysis tools for trucking companies are very useful. However, it is not likely that GEM could form the basis of these to ols. As a simulation model, it seems as the new version of GEM will require a lot of testing / analysis for the OEMs to get the required inputs. Users who are closer to the market would want something much simpler based on actual product offerings (like FuelEconomy.gov) but with pre

- loaded usage profiles. A significant step for truck operators achieving optimized fuel efficiency is getting the vehicle specified right for the intended job (engine, transmission, axle, etc). This step normally happens at the vehicle dealer. **Engine Targets and Test Procedures**  **Conversion factors.** It would be preferred to include conversions between various parameters such as g/hp

- h CO2 to efficiency or Brake Specific Fuel Consumption (BSFC).  **Undervalued Combustion.** Combu stion optimization is reported as one of the smaller contributors to improved fuel consumption, even at the end of the rule period (2027). Overall, the language seems to short

- sell how essential combustion optimization is as an efficiency multiplier and in achieving criteria emissions requirements. Also this section does not adequately emphasize increasing cylinder pressures and Brake Mean Effective Pressure (BMEP) to achieve higher engine efficiency. There is no mention of materials improvements or thermal management that is likely required to achieve higher engine efficiency. There is a notable absence of discussion of novel engine configurations or kinetic

- dominated combustion modes (HCCI, RCCI, etc).  **Undervalued Turbochargers.** The section understat es importance of devices with higher efficiency and higher boost capability. The SwRI modelling showed that a 5% improvement in turbocharger efficiency would yield about 2% fuel consumption reduction. It is not clear why this was not addressed, noting that this is not the same or redundant with turbocompounding. **“Alternative” Fuel Considerations**  **Natural gas engines.** Natural gas engines will have the same engine GHG standard as diesel engines with which they compete. Since the OEMs can now add their own engine map to GEM, we presume (but is not clear) that this includes natural gas engines so the certification can be the same as for diesel and gasoline powered trucks, and noting that there was no natural gas engine map in Phase 1 GEM. However, we did no t see this spelled out in the Notice of Proposed Rulemaking (NOPR). **Gasoline -**  **fueled HD option.** Since these regulations cover vehicles out to at least 2027, the

commenter recommends that the Agencies consider the emergence of high

- efficiency gasoline

fuele d, but diesel

- platform engines that would be economically attractive to operators. These would essentially be gasoline versions of today’s natural gas HD engines with low

- cost Three

-Way Catalyst (TWC) aftertreatment and low

- cost fuel. Fuels with higher oc tane are also a potential enabler of this approach. Gasoline compression

- ignition is a longer term alternative gasoline

- fueled option.