Fuel-Economy Falsehoods

Earth Island News

Bluewater Network

High gasoline prices, mounting evidence of global warming and national security concerns about US dependence on foreign oil have led consumers and policymakers to take a renewed interest in vehicle fuel economy. The situation is deeply troubling - our ever-growing fleet of passenger vehicles is guzzling gas and spewing out harmful emissions that contribute to global warming at an increasingly frenzied rate, while the average fuel economy of new vehicles has plummeted to its lowest point in 20 years.

Passenger vehicles are a significant source of carbon dioxide (CO2) and other greenhouse gas emissions that contribute to global warming. Cars and light-duty trucks are responsible for nearly 20 percent of annual US CO2 emissions (approximately 5 percent of global CO2 emissions) and these emissions are projected to grow significantly. Because every gallon of gasoline burned releases more than 20 pounds of CO2, the amount emitted is directly proportional to fuel economy.

Another cause for concern is our increasingly unsustainable consumption of petroleum. Every day the US consumes nearly 20 million barrels of oil, much of it in the gas tanks of passenger vehicles. This figure is projected to rise nearly 30 percent by 2020. Moreover, a growing proportion of petroleum consumed in the US is imported, primarily from the politically volatile Middle East. Burgeoning dependence on foreign oil has made the nation increasingly vulnerable to supply and price shocks, and has therefore become a major national security concern.

Furthermore, the price of gasoline has soared in the past two years, rising by 70 percent from 95 cents per gallon in February 1999 to $1.74 in May 2001. Historically, major economic downturns have followed oil price shocks.

Despite these trends, fuel economy has been falling steadily since 1988. According to the EPA, at 24 mpg, the average fuel economy of new passenger vehicles is at its lowest point since 1980. In reality, however, the situation is worse than it appears.

Troubled Tests
The 1973 Middle East oil embargo prompted Congress to enact legislation requiring auto manufacturers to ensure that their new vehicle fleets meet minimum average levels of fuel economy. Two separate Corporate Average Fuel Economy (CAFE) standards were established, one for automobiles and another for light-duty trucks (currently 27.5 and 20.7 mpg, respectively).

Compliance with CAFE standards is based on laboratory tests on new vehicles that measure exhaust emissions over prescribed driving cycles. Two separate tests are conducted, one simulating urban driving (the “city test”) and another simulating non-urban driving (the “highway test”). The EPA uses the results of these tests to calculate city and highway fuel economy values for each vehicle model, displayed on new vehicle window stickers. The agency also computes a “CAFE value” for each model, a weighted average of the city and highway test results (55 percent city/45 percent highway) that is used to determine manufacturers’ compliance with CAFE standards.

Since the CAFE program’s inception, motorists have complained that the actual fuel economy of their vehicles was significantly lower than that displayed on the window sticker. In 1985, the EPA adopted correction factors that lowered the city and highway test results by 10 and 22 percent, respectively, in an attempt to make the window sticker values more reflective of on-road fuel economy.

However, drivers continue to report that they are not achieving the advertised mileage. The reason is simple: the test procedures and correction factors no longer reflect today’s driving conditions. The city and highway tests are based on traffic measurements made some 30 to 40 years ago and the correction factors are based on surveys conducted in the late 1970s. Significant changes in population size and driving conditions have occurred in the interim, rendering the test procedures and correction factors obsolete.

America’s Changing Roads
Traffic congestion has grown in urban areas across the nation. According to the 2001 Urban Mobility Study, the average annual delay in traffic per person rose by 227 percent from 1982 to 1999, from 11 to 36 hours. This means that drivers are achieving significantly lower average fuel economy in urban areas than that derived from the city test.

The percentage of urban driving has also increased due to population shifts and increasing urban sprawl. The calculation used to determine auto manufacturers’ compliance with CAFE standards assumes that 55 percent of driving occurs in urban areas, but by 1999, the urban share of vehicle miles traveled had risen to 62.1 percent.

Furthermore, highway driving speeds have risen, due to the increase in the interstate speed limit and the availability of more powerful vehicles. The highway test assumes an average driving speed of 48 mph, whereas actual highway speeds today hover closer to 60 mph. Significant fuel-economy losses occur with speeds above 45 mph.

The test procedures and calculation methods used to determine fuel economy have not been updated to reflect these changes, and consumers and policymakers are being provided with misinformation that significantly understates the severity of the fuel economy problem. With global warming looming large on the horizon, and US petroleum consumption and imports climbing to dangerously unsustainable levels, the declining fuel economy of America’s passenger vehicles is a critical issue that must be addressed. The EPA must provide policymakers and the public with more accurate information on fuel economy in order to make the right choices in Congress and the marketplace.

What You Can Do. In October 2001, Bluewater Network petitioned the EPA to adjust the fuel-economy test procedures, calculation methods and/or correction factors to more accurately reflect on-road fuel economy. Please write EPA Administrator Christie Whitman urging her to grant Bluewater’s petition. For more information, see Bluewater Network’s website, www.bluewaternetwork.org.

The staff of Bluewater Network wishes to offer our heartfelt condolences to all who have been affected by the tragedies of September 11th and their aftermath. These events have shifted the nation’s priorities to important and immediate problems. Yet the need for ongoing work to protect the environment is as meaningful as ever. Bluewater Network has resolved to move forward with its work in the spite of such darkness and senseless violence.

Bluewater Network staff: Kira Schmidt, Elisa Lynch, Russell Long, Christine Corwin, Anne M. McCaw, Katy Rexford, Teri Shore, Sean Smith, Beth Strachan.

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