Bad policy ideas that refuse to die: Weight-based vehicle fuel economy standards edition

In arguments—sorry, policy discussions—about the best way to design vehicle fuel economy standards, there is a persistent view that when the United States adopted a system with targets indexed to vehicle size (specifically, footprint) instead of vehicle weight, it did so in order to favor US manufacturers, who produced the world’s largest vehicles and, especially, pickup trucks. This view is mistaken and has been frequently and firmly demonstrated to be so, but it keeps rearing its head, like some zombie policy. Most recently, it seems that some German and Chinese manufacturers have been taking this line in discussions leading up to new vehicle efficiency standards in Europe and China. So here’s one more attempt to finally lay this thing to rest.

I worked for Honda when the issue of whether to adopt size-based or weight-based standards in the US was being discussed. I was heavily involved in the process and it consumed much of my working life for a few years. For example, I wrote Honda’s comments on vehicle attribute adjustments and safety, which you can see here.

Not once did anyone involved in the process—NHTSA (National Highway Transport Safety Administration), OMB (Office of Management and Budget), EPA (Environmental Protection Agency), environmental groups, domestic and import manufacturers—suggest that size-based standards would favor the domestic industry or pickup trucks over weight-based standards. In fact, exactly the opposite was claimed by the US domestic manufacturers, who all supported weight-based over size-based standards.

But there’s no need to believe me. It’s all a matter of public record. During the rulemaking process, every US domestic manufacturer went on record as favoring a weight-based standard over a size-based standard. This is documented by NHTSA in their 2005 proposed rule on light-duty truck (LDT) Corporate Average Fuel Economy (CAFE) standards for the 2008–2011 model year (online here, page 51440, scroll down to see the quote):

 Recognizing the links between weight and vehicle safety, the Alliance, Daimler Chrysler, Ford, General Motors, Toyota, and Nissan expressed a preference for using weight in an attribute-based system. They also asserted that weight appears to have the best correlation to fuel economy, and that weight is currently used in fuel economy testing. Further, a weight-based system would distribute the burden of reducing fuel consumption equally to all manufacturers, preventing the systemic downsizing of vehicles and the associated detriment to safety.

NHTSA and the OMB opposed the wishes of the domestic manufacturers and selected size instead of weight because it was a better system, as it provided better incentives for safer vehicles and it provided incentives for lightweight materials.

In addition, if the purpose of adopting size-based standards were to favor pickup trucks, the US would have maintained a consistent slope for the target line of fuel economy versus size. Instead, the US flattened the slope for larger light trucks. This means that within the flat part of the target line, larger light trucks are held to the same standard as smaller light trucks, creating much more stringent requirements for the larger SUVs and pickup trucks – exactly the opposite of the claim that the system was designed to favor pickup trucks.

The most charitable spin to put on this is that those who persist in the view that the size-based standards were just a political favor are simply confused and are mixing up their arguments. It is true that the previous flat, unadjusted CAFE standard favored the US manufacturers’ international competitors and that NHTSA started the rulemaking on attribute (e.g., vehicle weight or size) adjustments primarily to help them out of that situation. But even if a size-based system is better for US domestic manufacturers than a flat, unadjusted system, it does not follow that the size-based system was selected because it favors US manufacturers over a weight-based system.

It is also possible that confusion about provisions in the recent 2017–2025 US CAFE/GHG regulation, which includes two huge breaks for pickup trucks, is coming into play here. One of those breaks is additional credits specifically for pickup truck technology; the second is substantially lower increases in the standards from 2017 to 2021 for light trucks, especially for the larger light trucks. But what this actually illustrates is that the size-based standard adopted by NHTSA for the 2011 MY light trucks disadvantaged pickup trucks and larger vehicles. Otherwise, there would be no need to create the special provisions in the 2017–2025 rule.

It is also important to understand that when NHTSA decided to change from a flat, unadjusted CAFE system to one including adjustments for vehicle attributes, it started a process of analysis and public comment that lasted for two and a half years. NHTSA started by issuing an Advanced Notice of Proposed Rulemaking (ANPRM) in December 2003, specifically targeted at exploring the advantages and disadvantages of different attribute adjustments. This was followed by a Notice of Proposed Rulemaking (NPRM) in August 2005, which included a specific proposal for a footprint-based system. Public comments were solicited and considered after both the ANPRM and the NPRM, with the final rule issued in April 2006. During this process a wide variety of adjustments were explored and analyzed in detail, including weight, footprint, vehicle pan area (overall length times width), towing capacity, engine horsepower, interior volume, gross vehicle weight, vehicle height and number of seating rows—plus combinations of different attributes. NHTSA and OMB selected footprint because their extensive analyses found it to be the best system. Again, it was selected over weight because it provided more appropriate incentives for safety and lightweight materials—over the objections of the US domestic manufacturers. By contrast, Europe did relatively little analysis of the advantages and disadvantage of weight and size when they adopted weight as the metric in 2009. They simply concluded that size information was not available. Later, in 2013, after further analysis, the European Parliament voted for vehicle footprint as an alternative compliance option from 2020 on, “in order to ensure a smooth transition to a future shift from mass to footprint” (see here for details).

One final point. If you read on a little further in the NHTSA NPRM, referenced above, a few paragraphs later is a reference to VW’s comments on size versus weight-based systems:

Volkswagen believes a weight-based system will reduce the regulatory incentive to reduce vehicle weight.

To be blunt: this incorrect idea about the genesis of size-based standards in the U.S. is usually found walking around in support of manufacturers’ attempts to defend a weight-based standard, despite its inherent disadvantages for improving overall fuel economy. Any argument based on such a completely—I won’t say deliberately—mistaken view of the historical development of those two approaches to setting fuel economy standards in the US ought to be seen as incredible.

For a detailed discussion of size and weight attribute adjustments, see this ICCT report. For a more concise briefing on the same topic, see here.