WASHINGTON - The X Prize Foundation and Progressive Insurance on Sept. 16 awarded $10 million to three teams who successfully completed the rigorous Automotive X Prize competition aimed at identifying the world's most fuel-efficient vehicles.

The winning teams -- Edison2 of Lynchburg, Va; X-Tracer of Winterthur, Switzerland; and Li-ion Motors Corp. of Mooresville, N.C. -- emerged from an original field of 111 competing teams, representing 136 vehicle entries from around the world. The winning vehicles were showcased to an audience of auto industry, business and government leaders. Each of the winning teams was also presented with a towering bronze trophy designed by Harry Winston Inc.

The Progressive Insurance Automotive X Prize was launched in 2008 to inspire a new generation of super fuel-efficient vehicles capable of achieving 100 miles per gallon or the energy equivalent (MPGe). The competition included nearly 30 months of vehicle and business plan development, on-track testing at Michigan International Speedway that entailed dynamic safety testing by partner Consumer Reports, and laboratory verification at the Department of Energy's Argonne National Lab.

The winners are:

$5 Million Mainstream Class Winner:

• Edison2 "Very Light Car #98" (Charlottesville, Va.)

• Economy: 102.5 MPGe

• Fuel: E85 ethanol

• Boasts the lowest drag coefficient of any car with four wheels tested in the GM wind tunnel and at the Chrysler Proving Grounds. The vehicle demonstrated over 100 MPGe on the test track. This was verified in the lab, under stringent testing conditions using a highly innovative small displacement engine. Its low weight of just 830 pounds reflects its use of lightweight materials, reduced engine displacement and a host of other weight-saving innovations.

$2.5 Million Alternative Side-by-Side Class Winner:

• Li-ion Motors Corp "Wave II" (Mooresville, N.C.)

• Economy: 187 MPGe

• Fuel: Battery Electric

• This side-by-side two-seat battery electric car was built on a lightweight aluminum chassis and weighs in at only 2,176 pounds, despite the weight of its powerful lithium-ion batteries. The Wave II demonstrated outstanding low mechanical and aerodynamic drag that resulted in 187 MPGe in combined on-track and laboratory efficiency testing, a 14.7s zero-to-60 mph acceleration time, and over 100 miles range over a real-world driving cycle.

$2.5 Million Alternative Tandem Class Winner:

• X-Tracer Team Switzerland "E-Tracer #79" (Winterthur, Switzerland)

• Economy: 205.3 MPGe

• Fuel: Battery Electric

• This tandem two-seat vehicle combines the best of motorcycles and automobiles. This clever design has two extra outrigger wheels that deploy at low speed to stabilize the vehicle. At 1436 pounds, the E-Tracer is able to deliver over 100 miles in range, led the competition with over 200 MPGe in combined on-track and laboratory fuel efficiency, and achieved a zero-to-60 mph acceleration time of just 6.6 seconds.