Visitors look at a new Mercedes-Benz SLS AMG E-Cell electric sportscar during the Frankfurt Motor Show, in Frankfurt, Germany, on Sept. 13, 2011. This is no battery-powered golf cart: the SLS E-Cell has 526 horsepower and four electric motors, one for each wheel. The car show is held at the Frankfurt Messe and runs from September 15-25. Photographer: Jason Alden/Bloomberg

Visitors look at a new Mercedes-Benz SLS AMG E-Cell electric sportscar during the Frankfurt Motor Show, in Frankfurt, Germany, on Sept. 13, 2011. This is no battery-powered golf cart: the SLS E-Cell has 526 horsepower and four electric motors, one for each wheel. The car show is held at the Frankfurt Messe and runs from September 15-25. Photographer: Jason Alden/Bloomberg

Frankfurt Motor Show

Mercedes-Benz SLS AMG E-Cell
Mercedes-Benz SLS AMG E-Cell

Visitors look at a new Mercedes-Benz SLS AMG E-Cell electric sportscar during the Frankfurt Motor Show, in Frankfurt, Germany, on Sept. 13, 2011. This is no battery-powered golf cart: the SLS E-Cell has 526 horsepower and four electric motors, one for each wheel. The car show is held at the Frankfurt Messe and runs from September 15-25. Photographer: Jason Alden/Bloomberg

Mercedes-Benz
Mercedes-Benz

The body of a Mercedes-Benz automobile hangs in the company's show hall during the Frankfurt Motor Show. Photographer: Jason Alden/Bloomberg

Chrysler Jeep
Chrysler Jeep

A visitor looks at a Chrysler Jeep, mounted on a wall on the company's stand during the Frankfurt Motor Show. Photographer: Jason Alden/Bloomberg

Mercedes-Benz F125
Mercedes-Benz F125

A Mercedes-Benz F125 hydrogen-powered concept car is driven onto the stage during the Frankfurt Motor Show. The F125 employs such advanced features as composite body materials and a navigation system controlled by hand gestures, and it has zero emissions. Photographer: Hannelore Foerster/Bloomberg

Touch Up
Touch Up

An employee cleans the underside of a Ford Focus automobile display ahead of the Frankfurt Motor Show. Ford is showing a high-performance version of its small car. Photographer: Jason Alden/Bloomberg

VW Beetle
VW Beetle

A visitor makes a phone call as he sits inside the new Volkswagen Beetle during the Frankfurt Motor Show. A turbocharged version of the new Beetle is expected in the U.S. by 2014. Photographer: Jason Alden/Bloomberg

BMW i8
BMW i8

BMW's i8 concept electric automobile sits on display during the Frankfurt Motor Show. It has a plug-in hybrid gas-electric drive system and can get to 62 mph in 4.6 seconds. Photographer: Hannelore Foerster/Bloomberg

Ford Evos
Ford Evos

A Ford Evos concept automobile on display at the Frankfurt Motor Show. The car has a distinctive profile, including four gull-wing doors, and personalized technology to control energy use, entertainment, and navigation. Photographer: Hannelore Foerster/Bloomberg

Porsche 911 Carrera S
Porsche 911 Carrera S

A worker polishes the new Porsche 911 Carrera S as it sits on display during the Frankfurt Motor Show. Porsche overhauled the 911 for the first time since 2004, making it lighter, faster (top speed: 179 mph), and more fuel efficient. Photographer: Jason Alden/Bloomberg

Renault Twizy
Renault Twizy

A Renault Twizy electric automobile is connected to a charging station at the Frankfurt Motor Show. The tiny Twizy is less than 8 feet long and 4 feet wide, and runs for about 60 miles on a three-and-a-half hour charge. Photographer: Jason Alden/Bloomberg