According to Mark Perry, director of product planning and strategy for Nissan North America, drivers of the Leaf electric car almost never go more than 37 miles in a single day, and the average length of a single trip is just seven miles. In other words, the Leaf's 70-plus-mile range is plenty enough for the all-electric machine to satisfy the requirements of a "primary-use car."
This data has been extracted from the daily use cycles of the roughly 7,500 Leafs currently roaming the streets in the U.S. It's probably safe to assume, though, that the majority of these Leaf drivers knew going in that their average driving routines wouldn't be too much for the electric car to handle.
In any case, the Leaf seemingly proves that, for at least a sizable portion of the population, an electric car is completely viable.