Toyota's hybrids often soar in gas-mileage ratings, but its cars fare average, or worse. The Scion tC's a good example: it's just okay by absolute standards, and a bit of a gas swiller compared to Toyota's own larger, more useful Camry sedan.
On the EPA scale last year, the tC earned ratings of 23 miles per gallon on the city cycle, and 31 miles per gallon highway. The numbers apply to versions with either the automatic or manual transmission. While those figures are an improvement of several miles per gallon over the first-generation tC, they're just not that great overall. The Camry will best the tC on the highway cycle, and so will more spacious hatchbacks like the Kia Soul, which gets up to 33 mpg on the highway.
In past versions of the tC we've seen quite low figures in real-world driving as well—likely the result of rather low gearing that keeps revs up for a sporty feel.