Jan. 14, 2008 Green's the theme at the 2008 North American International Auto Show in Detroit this week as nearly every major car company previews new designs and technologies geared toward reducing the environmental impact of their vehicles. The event is also serving as a platform for executives to unveil their long-term sustainability strategies. Here are some highlights.

GM

GM is partnering with renewable energy company Coskata to produce a cheaper kind of cellulosic ethanol, a fuel that can be made from many different materials including wood chips and orange peels. The car maker has just introduced a prototype Humvee that runs on E85, an ethanol blend.

Battery power is another GM focus. The company is currently testing its Chevrolet Volt electric car and will soon begin testing a battery-equipped Chevrolet Equinox. GM has also unveiled the Cadillac Provoq, a battery-powered four-wheel-drive vehicle.

Ford

Ford expects its new Ecoboost engine technology to offer small cars and light trucks up to 20% better fuel economy and cut carbon dioxide emissions up to 50%. The company plans to equip 500,000 vehicles with Ecoboost engines by 2012.

Honda

Calling global warming "the number one environmental issue," Honda CEO Takeo Fukui says he wants new hybrid models to make up 10% of the company's global sales by 2010.

Daimler

Amid tightened emissions regulation, Daimler says it will boost R&D spending to 4%-5% of revenue, up from 3.5% today. Daimler is also banking on a largely untapped U.S. market for tiny cars best equipped for city driving; the company will be delivering its first two-seat Smart cars to the U.S. next week.

BMW

Company chairman Norbert Reithofer touts past successes in improving fuel efficiency and reducing emissions in existing models, but says BMW will release its first hybrid vehicle in 2009.

View a photo gallery of new green concept cars, including the Cadillac Provoq, here.