Pedestrians and other drivers alike look at the 2014 Scion iQ and simply assume that it gets 50, 60, even 75 mpg.
It doesn't. With the same amount of frontal area to push through the air, and a substantial safety structure packed into its tiny overall length, the Scion iQ is not even the most fuel-efficient gasoline car on U.S. roads--let alone equal to most of Toyota's growing range of hybrids. The Scion iQ is rated at 37 mpg combined by the EPA (36 mpg city, 37 mpg highway).
And that number is significantly below the light five-door Mitsubishi Mirage that's new for 2014 and pegged at 40 mpg combined. (In a short road test, we saw 43 mpg in a pre-production Mirage.) The Scion and Mitsubishi probably won't compete--the Scion has a base price $2,000 higher, for one thing, and it's more of a style statement--but it does underscore that ultimate smallness doesn't translate to large fuel efficiency in today's market.
The Scion iQ does, marginally, do better than the aging Smart ForTwo, which has a combined rating of 36 mpg. And it's a better driving experience, though that's not a very high bar. But part of its efficiency rating is due to a surprisingly low CVT final ratio, which pegs the engine at almost 4000 rpm at U.S. highway speeds of 70 or 75 mph. This is clearly a city car, and designed for temperate use to boot. During several tests comprised of the worst-case scenario--both highway miles and aggressive urban stop-and-go--we saw gas-mileage readouts of less than 30 mpg.
So while 37 mpg is better than most other gasoline cars, you'll do better with a hybrid (and get more interior space as well)--or spend less money (and get more interior space) with the far less stylish Mitsubishi Mirage. It just underlines the iQ's position as a style statement rather than ultra-efficient transportation. On an absolute scale, and against the Smart ForTwo, it's a more efficient vehicle. Against certain other cars and many hybrids, not so much.