With a 1.3-liter 4-cylinder engine and a low curb weight (U.S. spec curb weight isn't available, but the Toyota iQ sold in Europe weighs in at 1,896 lbs, or about 90 lbs more than the Smart ForTwo sold here), our partners at Autoblog speculate that fuel economy will be "in the high 30s, which is reasonable but far from overwhelming for such a small package." 30 MPG driving just isn't as impressive for a small car these days when a vehicle like the Ford Mustang can hit 31 MPG on the freeway (to its credit, the Smart ForTwo squeezes out 33 city and 41 highway from its 1.0-liter, 3-cylinder engine).
Fuel capacity is 8 gallons on the European iQ models (again, no word yet from Scion on the capacity of the U.S. fuel tank), so a total range could be as high as 300 miles but as low as 200 miles with aggressive city driving (which is the type of driving Scion is expecting for most iQ buyers). Until we know specific numbers from Scion, we'll hold out hope these numbers will be higher.