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.

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. Nisan, 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.

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.

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.

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. 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.

Smart Charging with Smartphones

Leading up to the introduction of the all-electric Leaf in late 2010, Nissan has been thinking hard about how people will take to the new reality of owning, charging and driving a battery-powered vehicle. Because modern electric cars are heavily computer-driven, the door is open to a slew of new capabilities that might help drivers adapt.

In the summer of 2009, Nissan displayed several interesting prototypes in Japan, including an iPhone app that lets users control the charging mode of their car from afar. Using the app, the Leaf owner can tell the car when to start charging, and the car can reply with SMS alerts when the battery is full. A smartphone could even be used to access the Leaf's climate control, pre-heating or cooling the car while it's still plugged in, saving it from performing this battery-draining task once on the road.

Pit Stop Battery Swap

While boosters of electric cars assure us that battery technology is improving by leaps and bounds, the first affordable EVs probably won't do much better than 100 miles on a charge. Promises vary, but charging a drained battery will likely take between four and 10 hours (depending on the voltage of the charging station), pretty much ruling out the long-distance road trip. But Israeli startup Better Place says it has you covered. Pull your EV into Better Place's automated drive-through swap stations, and it can remove your depleted battery and exchange it for a fresh one in just over 60 seconds.

A Hot Piece of Asphalt

A sweltering stretch of blacktop may not seem like a useful resource, especially when you're ensnared in summer traffic. But what if all that heat could be stored up for winter? Invisible Heating Systems in Scotland is already installing systems that harvest the thermal energy of hot roads using a network of water-filled tubes running below the paving surface.

By pumping the hot water into giant underground "thermal batteries" made of moist sand, the heat can then be drawn upon in the winter to warm homes. An average airport runway, the company estimates, could heat 2,500 homes with 50 to 90 percent lower carbon-dioxide emissions. And because these roads stay warm in the winter, they could offer safer driving and eliminate the need to spray harmful, paint-eating salt.

The Stackable CityCar

As our urban areas become more cramped each year, the Smart Cities program at the Massachusetts Institute of Technology is inventing ways to fit more mobility into less space. The CityCar is a proposal for a 2-passenger electric vehicle that would be available to commuters on an as-needed basis. These micro cars would be parked tip to tail in special racks (like luggage carts at the airport) at key locations around the city, while a jointed driveshaft allows the vehicle to scrunch up to consume even less space.

All Meshed Up

Robin Chase co-founded Zipcar, the most successful car-sharing business to date, and then moved on to create GoLoco, a high-tech mashup of social networking and carpooling. But her real fervor is in creating a distributed mesh network that will enable America's millions of cars to share up-to-the-second information.

By weaving our cars into a decentralized network of data sharing, the personal transportation experience can be made radically more efficient. Imagine not waiting at a red light at an empty intersection, or being able to pay for car insurance by the mile instead of by the year. If plugged into such a peer-to-peer system, your car could learn your commute, then warn you before getting into a traffic snarl, suggesting alternative routes or alternative modes like public transit.

By Nguyen Minh