US to cut CO2 emissions from cars and light-duty trucks

A proposal to reduce greenhouse gas emissions from road vehicles in the USA will apply for model years from 2012.

The United States Environmental Protection Agency (EPA) and the Department of Transportation’s National Highway Traffic Safety Administration (NHTSA) presented in September a joint proposal to reduce greenhouse gas emissions and improve fuel economy in road vehicles.

The standards proposed would apply to passenger cars, light-duty trucks, and medium-duty passenger vehicles, covering model years 2012 through 2016. They require these vehicles to meet an estimated combined average emissions level of 250 grams of carbon dioxide (CO2) per mile (g/mi) in model year 2016, equivalent to 35.5 miles per gallon (mpg) if the automotive industry were to meet this CO2 level all through fuel economy improvements.

These proposed rules were developed in response to President Obama’s call for a strong and coordinated federal greenhouse gas and fuel economy program for passenger cars, light-duty trucks, and medium-duty passenger vehicles (see AN 2/09, p. 21).

EPA proposes to introduce emissions standards for CO2 based on footprint curves, where each vehicle has a different CO2 emissions compliance target depending on its footprint value (related to the size of the vehicle). Generally, the larger the vehicle footprint, the higher the corresponding vehicle CO2 emissions target.

Table: Projected fleet-wide emissions compliance levels under the proposed footprint-based CO2 standards (g/mi) and corresponding fuel economy (mpg)

The table shows the projected fleet-wide CO2 emission level requirements for cars and light trucks under the footprint-based approach. These requirements are projected to increase in stringency from 261 to 224 g/mi for cars, and from 352 to 302 g/mi for light trucks, between model year 2012 and model year 2016. The average vehicle CO2 emissions compliance level for the model year 2016 standard is 250 g/mi, corresponding to 35.5 mpg, if all reductions were made through fuel economy improvements. The proposal and related documents can be found at EPA’s Office of Transportation and Air Quality (OTAQ) web site:

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