FORTUNE -- Earlier this month, President Obama proposed spending $2 billion over the next decade to find an alternative to operating cars and trucks on oil -- an idea that has been catnip to the political class. Previous presidents and congresses have sought favor with voters by spending on gas-electric hybrids, biofuels, advanced batteries, fuel cells, solar, and other technologies. So far, no breakthrough has been made; gas-sipping engines still power more than 95% of new cars.
There is another promising strategy: investing in autonomous and semi-autonomous systems. Such technology, which prevents or corrects driver error, could minimize collisions, making driving so safe that future vehicles will be built with far less weight and mass than today. Automakers point out that lighter weight automatically translates into less gasoline burned. Lighter vehicles also could make the power of batteries more useful and extend their range.
Carmakers so far aren’t asking for government help to develop autonomous systems. (Assistance from Washington in the form of subsidized research typically isn’t refused.) The subject of autonomous systems so far hasn’t reached the political arena. "Autonomous related technologies, even if they fall short of making a vehicle fully autonomous, hold the potential to reduce fatalities and injuries on our roadways," says Jon Lauckner, GM's (gm) chief technology officer.
Lauckner said that GM’s Cadillac division will offer a feature called “Super Cruise” before the end of the decade. Super Cruise will allow a driver at highway speeds to take his or her hands off the wheel. The car will remain centered in its lane, and slow down or stop for slower traffic ahead or if a car cuts in front of it.
A driver using Super Cruise must pay attention to the road, GM says -- but he or she also can safely text or even take eyes off the road. Volkswagen’s Audi division said it soon will equip its A8 flagship with “traffic jam assist” that steers and avoids collisions at low speeds on highways.
It might take years -- or even decades -- for systems like lane-change warning, car-to-car communication, adaptive cruise control, advanced vision and braking to evolve into fully driverless technology. Once driverless cars are used in great number, many engineers believe, accidents that result from driver error will decline sharply, occurring only under extreme or unusual circumstances.
"When we show this technology can have that effect,” Lauckner says. “Regulators might consider adjusting the rules that would allow automakers to fundamentally change the way we design vehicles, allowing a significant amount of mass to be removed from cars."
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Today’s Ford (f) Fusion midsize sedan, which weighs 3,427 pounds, achieves fuel economy of 22 miles per gallon in the city, 34 miles per gallon on the highway. A Toyota (tm) Yaris, at just under 2,300 pounds, gets fuel economy of 30 miles per gallon in the city, 37 miles per gallon on the highway.
In other words, reducing a car’s weight by 1,000 pounds or so translates into almost 90 gallons less fuel burned annually. Smaller, lighter vehicles powered by batteries would feature longer range than today. Presumably, future midsize sedans wouldn’t need much of the reinforcing steel that today helps a car pass federal crash tests. Lighter materials might replace steel. The vehicle wouldn’t need airbags or much of the safety paraphernalia that keeps passengers and driver safe in the event of a collision.
First, however, automakers must prove that autonomous and semi-autonomous systems -- sometimes called “assisted driving” -- can reduce drastically the number of accidents and fatalities, now numbering about 35,000 a year in the U.S. That’s only likely to happen as features like Super Cruise become more common.