The recently-proposed CAFE standards will affect vehicles’ required fuel economy based mainly on their footprint, which is defined as the relative area within its four wheels, or basically a product of their track and wheelbase. The proposal has already spurred theories as to how automakers will attempt to side-step or maximize their chances at meeting the rules, by moving vehicles to different categories through manipulating their footprint.
Critics also wonder why the NHTSA wouldn’t use weight or overall vehicle size as the standard. In its proposal, the NHTSA defends its choice by noting footprint is the most difficult to change than any other attribute. Next-generation models are already being developed, for example, and changing its foundation by either stretching its wheelbase and / or widening its track, means effectively starting the design and engineering from the ground up. In the long-term, however, it is possible cars will grow, but not only to reflect manufacturers wishes to fit them into a less stringent category, but also to reflect the customer’s needs for more interior space.
And such growth is not a recent trend. As examples, before the proposals were even dreamt up, the latest Chevy Malibu has a wheelbase that is six inches longer than its predecessor, while the Toyota Camry ’s grew by 2.2 inches. The Honda Civic, which itself grew by 1.2 inches in wheelbase, is no longer the automaker’s entry-level car, with the Japan and Europe-sourced Fit taking that honor.
While the proposed rules are still not law, there is a 7.7mpg disparity on average, between products from Chrysler (33.6mpg) and Porsche (41.3mpg), which sit at opposite ends of the range. For trucks, the difference is smaller, at 6.3mpg on average, with Suzuki at the high end and GM at the low, required to average just 27.4mpg, not that far off the current 22.5mpg standard. The requirements would also take into account the numbers in which a vehicle is built, making it more complicated.
