Jeffrey M. Sims ● President 

 7001 Heritage Village Plaza ● Suite 220 ● Gainesville, VA 20155 ● 703-549-3010 

October 16, 2014

Phase 2 HD GHG Trailer Team 

Attn: Tad Wysor 

2000 Traverwood Dr 

Ann Arbor, MI 48105 

Dear Sirs, 

The Truck Trailer Manufacturers Association (TTMA) is an international trade association representing 

producers of over 90% of the trailers manufactured in the United States. We are pleased to be able to 

work with EPA as it considers trailer-related regulatory strategies to implement the President’s directive 

to expand on gains of fuel economy/greenhouse gas emissions for heavy duty vehicles. 

Fuel-saving/greenhouse gas reducing techniques are best left to the free market, where, along with 

cooperative government programs like SmartWay, trailer purchasers can best assess the real-world 

fuel/greenhouse gas savings and purchase those that will actually create savings. 

When considering these fuel-saving/greenhouse-gas-reducing devices (GHG devices hereafter), the 

trucking industry has already seen where they are effective and where they are not. 

Based on our experience, various types of heavy duty truck trailers could be classified into certain 

categories that ought to be considered separately. These are broad categories in which there are 

considerable variations that are significant to fuel economy/greenhouse gas emissions, but it is a starting 

point. The categories are: 

53’ or Longer Straight Floor Dry Vans – These are the workhorses of long haul and most likely to be 

outfitted with GHG devices. Still, there are many applications where certain types of GHG devices are 

not worthwhile or are actually counterproductive. For example, if a particular GHG device interferes with 

trailers made to work on rail cars in a trailer on flat car (TOFC) situation, it would result in freight being 

diverted from TOFC service and result in a net increase in fuel consumption and greenhouse gas releases. 

Less than 53’ Straight Floor Dry Vans – These configurations are almost exclusively used in short haul 

service with a noteworthy exception being Doubles used between distribution centers of package delivery 

services (e.g. UPS, FedEx). Most of these trailers gain little benefit from Aerodynamic GHG devices as 

their average speed is too low. 
Reefers – These specialty vans often travel longer hauls than similar dry vans, however, given the density 

of the cargo they haul (food products tend to be relatively heavy), they run up against the weight limit 

(weigh-out) often. In those cases, every pound of weight added to the trailer is one pound less of cargo it 

can carry. Any gains to be had from aerodynamic based GHG devices would be lost in extra trips 

required to haul the displaced cargo. 

Cargo Tanks – A trailer equipped with a liquid tight vessel for carrying liquids or dry bulk products. 

These trailers are usually highly specialized to the need of the commodity being hauled, and also 

frequently weigh-out. Extra trips with these trailers carry an additional risk, as they are often carrying 

hazardous commodities. 

Lowbeds – A lowbed trailer is a platform trailer constructed to provide minimal ground clearance beneath 

the loading deck and designed to transport heavy, often times concentrated loads with high centers of 

gravity. Like Cargo tanks, these trailers are often highly specialized for the load/service they are in. 

Frequently, lowbed trailers are hauling construction equipment to locations of inconsistent terrain and 

generally for relatively short distances. 

Flatbeds & Others – A trailer chassis consisting of load-carrying main frames and a flat loading deck 

without permanent sides or roof. Flatbed trailers often carry large/unusual objects, and other types of 

trailers are highly specialized for a particular niche market that precludes extensive modification. 

Noteworthy among the other category is the intermodal chassis. A chassis is a skeletal structure on which 

a container is placed in order to provide transportation from a ship or railcar across the road system. 

When the chassis is without its payload (container) the structure is narrow, about 40” wide. In order for 

an aero device to be functional with the cargo being carried, the device must extend from the main 

structure approximately 25”. During handling operations in the ship and rail yards, the chassis is handled 

in the area where these structures would be mounted, precluding such devices. 

We polled our members to assess market penetration of various GHG devices by type of trailer & device. 

Our findings are summarized in Figure 1. 

Figure 1 

53 or longer 

van

under 53 foot 

van refrigerated flat bed cargo tank

lowbed/ 

heavyhauler all other

aero side skirts 35.4%/34% 1.7%/1% 19.0%/20% 0.0%/0% 0.7%/0% 0.0%/0% 0.0%/0%

boat tails 0.2%/0% 0.0%/0% 0.0%/0% 0.0%/0% 0.0%/0% 0.0%/0% 0.0%/0%

gap reducers 0.0%/0% 0.0%/0% 0.0%/0% 0.0%/0% 0.0%/0% 0.0%/0% 0.0%/0%

low rolling tire wide single 2.2%/2% 1.6%/2% 2.0%/2% 1.9%/1% 2.0%/0% 1.8%/0% 0.6%/0%

low rolling tire duals 85.6%/82% 90.6%/95% 86.3%/82% 39.4%/16% 7.7%/0% 5.3%/0% 28.5%/4%

ATIS 40.2%/40% 26.6%/29% 46.0%/46% 20.0%/10% 7.3%/5% 3.3%/5% 13.3%/10%

under belly 1.9%/2% 0.5%/0% 0.9%/0% 0.0%/0% 0.0%/0% 0.0%/0% 0.0%/0%

flow thru mud flaps 10.0%/11% 24.0%/9% 3.7%/0% 0.0%/0% 0.0%/0% 0.0%/0% 0.0%/0%

wheel covers 0.0%/0% 0.0%/0% 0.0%/0% 0.0%/0% 0.0%/0% 0.0%/0% 0.0%/0%

Manufacturer Observed Market Penetration

Average/Median
Outside of the 53’ or longer van and refrigerated trailers segment, all adoption is solely due to market 

demands and thus reflects adoption of devices where they actually make economic sense. What we find is 

that gains to be had from Low Rolling Resistance (LRR) dual tires in the most popular long haul vehicles 

are the ones that are most justified (highlighted in green). Other areas, highlighted in yellow, represent 

potentially effective gains or industry compliance with CARB regulations in the case of long vans and 

reefers. The areas highlighted in red indicate combinations that are not practical due to type of trailer, 

typical freight, or operating conditions. 

The similarity in response between Flatbed and All Other trailers indicate that they ought to be considered 

in the same fashion, where LRR duals and Automatic Tire Inflation Systems (ATIS) show some promise. 

The similarities in response between Cargo Tank and Lowbed manufacturers and their uniform low 

adoption rates indicate practical problems with GHG devices and indicate that these types of trailers ought 

to be exempt from the regulation. 

Work Performing Equipment: In other areas of regulation, DOT has recognized the need for regulatory 

flexibility when trailers are equipped with “work performing equipment” in areas where they might 

otherwise require devices to be mounted. This would include lifting or handling locations, such as the 

main beam of an intermodal chassis, or lift points on TOFC service trailers. To avoid the worst of niche 

products and small businesses being inadvertently crushed by GHG regulations, exceptions for trailers 

outfitted with work performing equipment in areas typically fitted with GHG devices need to be crafted in 

any proposed rule. 

Cost-Benefit Calculations: We believe that requirements that each trailer design and its accompanying 

GHG devices be aerodynamically- or fuel-consumption tested will be cost prohibitive. Requiring this 

would cause major harm to small businesses building short runs of trailers, and will add so much cost that 

end users will divert freight to other types of trailers with worse performance. Freight Diversion is a 

difficult problem to quantify, one which the DOT is currently grappling with as a part of their MAP-21 

Size & Weight Study. 

We have heard reports that as a result of California’s overly broad and aggressive regulations, end users 

are shifting freight increasingly to intermodal containers on chassis. The fuel consumption/greenhouse 

gas properties of these chassis/container combinations hauled exclusively over the road are far worse than 

the unmodified van trailer they are displacing. We understand that the scope of the regulations under 

consideration does not allow for requiring changes to intermodal containers, so any regulation that lacks 

flexibility for the end user will likely see this sort of freight diversion problem. 

Additionally, we hope to see that when the final set of Phase 2 regulations are announced, there will be 

detailed cost-benefit analysis that factors in not only the full costs of the various GHG devices both to buy 

& install and to operate, but also considers various weight penalties to the maximum permissible loads 

which will result in increased trips. These regulation-induced trips will impose not only a cost in terms of 

increased costs to operate (e.g. buying/operating more equipment, hiring more drivers), and increased fuel 

consumption/greenhouse gas releases, but will also create societal costs from increased safety risks caused 
by putting more trucks on the nation’s roads. Every trip carries a statistical risk (that regulators, 

manufacturers and operators are all trying to keep to a minimum) of some sort of accident. 

We firmly believe that GHG devices must not increase risk to the motoring public. 

Conclusion: We believe that market forces are the best route to affect GHG reduction/fuel savings for 

heavy-duty truck trailers. The role of government in vetting various strategies through programs like the 

SmartWay program speeds the adoption of these devices by providing an independent review of 

marketers’ claims. The best way to achieve the President’s directive is to expand the SmartWay program 

into other trailer designs/usage patterns and monitor adoption rates. By examining adoption rates of 

various strategies, you can guide the testing and data collection studies and re-evaluate the cost-benefits 

based on the various challenges facing real-world end users. As the program’s evaluation of prospective 

savings comes closer to real world conditions, with the appropriate primary variables such as design type 

and average fleet speed being addressed, end users will be able to accurately specify the best solutions for 

their particular case. Where there are discovered disconnects between a given technology and usage 

patterns, they can be subjected to follow up investigations and folded into follow-on rulemaking. 

We hope you find this information useful and we appreciate this chance to work with the EPA as you 

begin to consider regulations aimed at the trailer industry. 

Sincerely, 

John Freiler 

Engineering Manager 

Truck Trailer Manufacturers Association