Tesla promises coast-to-coast driving in its electric cars

The Tesla Model S fell short of a perfect score in our testing for one simple reason: You can't jump in it any time you want, and drive to absolutely any point on the map at a moment's notice. But, Tesla has just announced a big step in addressing that problem.

To that end, the electric-car startup automaker has announced it will triple the size of its network of Supercharger stations from currently eight to 27 by mid summer. By 2015 it will build enough of the electric car filling stations to allow Tesla drivers to drive cross-country. (Read about our experience rapid charging at a Tesla EV "Supercharge" station.)

Tesla's Superchargers will pump about 160 miles worth of electricity into the cars' batteries in a half hour. Many Superchargers will be placed at Interstate rest areas, where travelers can take advantage of Internet connections, food, and restrooms while their cars charge. While quite the convenience, a 20-minute stop is not the same as a three-minute gasoline fill up.

The company currently has Superchargers set up along three major travel corridors: San Francisco to Los Angeles; Los Angeles to Las Vegas; and Boston to Washington, D.C. Now the company will add venues allowing travel from Portland, Ore., through Seattle, to Vancouver, B.C.; Austin to Dallas, and in Illinois, and Colorado and Florida. It will fill in more stations in its East Coast network to make travel there easier. (An interactive map showing travel possibilities.)

Within a year, Tesla says it will be possible to travel diagonally across the country from Los Angeles to New York using Supercharger stations. It will build more networks in Texas, Florida, and the Midwest; stations connecting Ottawa to Montreal; and across North and South Carolina into Georgia.

Between the cars' big batteries, and its fast chargers, Tesla is eliminating a major limitation of the car for more people. Although, the range of about 200 miles experienced in our testing shows that the Model S could satisfy the typical daily driving needs for most Americans.

Read our complete Tesla Model S road test for more details, and check the Ratings to see how it compares to other luxury cars and electric cars.

—Eric Evarts