EMISSIONS STATEMENT

HOW “CLEAN” IS THE U.S. CAR FLEET TODAY? WE MEASURED TO FIND OUT

- NICK MOLDEN

In 2012, MotorTrend teamed with the world’s preeminent real-world on-road emissions testing company—U.K.-based Emissions Analytics—and began emissions-testing many vehicles that pass through our revolving test fleet. Our prime motivation was to measure real-world fuel economy, which we’ve reported in many of our vehicle evaluations as Real MPG. But because Emissions Analytics’ proprietary EQUA testing procedure is functionally similar to the EPA’s (which determines fuel economy by capturing and analyzing the products of combustion), it would also reveal any cheating on other controlled emissions.

It’s report card time: How “clean” is the U.S. fleet, judged by our own EQUA measurements?

The Basics

Of the 817 vehicles tested, none demonstrated a whiff of Volkswagen Dieselgate-style noncompliance in terms of regulated air pollutants from the tailpipe. Nitrogen oxides (NOx) emissions from the gasoline vehicles tested an average of 0.023 g/mile—less than half the regulatory limit for cars (0.050 g/mile). Even light- and medium-duty diesels from the last five years average just 0.036 g/mile. Looking at carbon monoxide (CO), gasoline and diesel vehicles emit just 0.267 g/ mile and 0.228 g/mile, respectively, compared to a regulated limit of 1.700 g/mile. Put simply, modern regulations have given rise to powertrain technologies that have slashed the amount of these pollutants expelled into the air.