SARTRE (© Ricardo)Click to enlarge picture

The European Union is embarking on a three-year trial to test whether computer-controlled highway convoys can safely reduce traffic congestion and emissions. Safe Road Trains for the Environment, or SARTRE, will wirelessly link as many as seven vehicles in tight formation behind a professional driver.

While they may sound nuts, these wild and innovative ideas could be the future of mobility. From electric cars that charge without wires to remote-controlled commuter convoys, plenty of far-fetched technologies are in the works that could green up the way we drive and make our roads do more than just lie there.

Some are still tantalizing concepts, others are just around the corner, but as the second-largest source of carbon-dioxide emissions on the planet, transportation is long overdue for some fresh ideas.

Road Train
During a race, NASCAR drivers tend to run bumper-to-bumper on the track in a technique they call "drafting." It cuts turbulence and lets both leader and follower go faster. But don't try this on the way to work (it's called tailgating on the street, and it is illegal), unless of course your car is on autopilot.

Sound nuts? The European Union has commissioned a three-year study to test "platooning," or automated road trains that roll down the highway in line behind a professional driver, just like railroad cars follow a locomotive engine. Here's how it works: A commuter would enter the highway and signal a convoy already heading in his or her direction. The driver would then relinquish control of the vehicle to a professional driver at the head of the convoy, whose job it would be to guide the vehicle into line and then operate it by remote control. The driver could then let go of the wheel and watch TV, write an e-mail, or just relax as the car drives in tight formation with up to six other vehicles. According to the designers of Safe Road Trains for the Environment (SARTRE), platooning could save 20 percent on fuel consumption and cut down on commute time and congestion.

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Wireless Charging
Every day it seems more inevitable that electric cars are our fate. If true, we'll all soon become accustomed to charging up at home, at work and probably where we shop. Nissan, maker of the forthcoming Leaf electric vehicle, is already experimenting with ways to make the chore more of a no-brainer. Using magnetic induction — the same technology found in electric toothbrushes and pacemakers — the automaker is devising ways to charge EV batteries wirelessly. Nissan has demonstrated a system that can wirelessly charge a parked car, but the Japanese automaker is also tinkering with the next frontier: implanting induction charging strips into roads so cars can juice up on the go.

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Kinetic Roads
In the United Kingdom, the Sainsbury grocery chain is experimenting with special plates implanted in its parking lots that produce power as cars drive over them. Only a little energy is harvested from the pressure of each passing car, but tallied up, it's enough to run the grocery store's checkout counters.

This type of kinetic-energy harvesting is drawing increasing interest in many industries. A nightclub in Rotterdam, Netherlands, even has a kinetic dance floor to generate power from the movement of its guests.

But when it comes to cars, skeptics cite the first law of thermodynamics (energy can't be created or destroyed), rebuking systems like Sainsbury's on the grounds that such a thing must slow a car down, thereby forcing its engine to work harder and spew more pollution.

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Speed Bumps
Where Sainsbury's brand of technology may make more sense is in spots where cars are already using their brakes to slow down. Special speed bumps leading up to a toll booth or traffic signal could help slow a car and spare the brake pads while recapturing some of that momentum, turning it into electricity (not unlike the way a hybrid's regenerative braking system reclaims friction used during deceleration).

New Energy Technologies in Burtonsville, Md., is claiming to do just this. Its Motion Power Energy Harvesting system consists of a series of short, angled flippers protruding from the road surface. As the car rolls over the fins, they depress, helping to slow the moving vehicle and make electricity in the process. The company is testing the system at a Holiday Inn Express in Maryland and a Burger King drive-through in North Carolina.

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Higher-Tech Hybrids
Once only the obsession of tech-happy hobbyists and college engineering classes, the plug-in hybrid car is about to become a regular sight around the neighborhood. In late 2010, General Motors will introduce the Chevy Volt, a car that will charge up in eight hours and travel roughly 40 miles in electric mode, after which it can rely on its backup gasoline engine. Scheduled to first hit the California market, the Volt will be priced at around $40,000.

Do you have any ideas how to make driving more environmentally friendly?

Toyota, currently the leader in hybrids, has been reluctant to embrace the plug-in, but has decided to dive into the fray; in late 2011 it will start selling a car that charges in 100 minutes and can do 14.5 miles of pure electric driving.