Besides pollution and contribution to climate change, cars and trucks have one other significant drawback: they can injure or kill people in an accident.
Still, more than 37,000 people in the United States alone died in 2008 as a result of auto accidents, according to the U.S. Department of Transportation's Fatality Analysis Reporting System [source: Fatality Analysis Reporting System].
But what if collisions themselves became a thing of the past?
Several companies are working on it. Volvo, the Swedish car company that equates its brand with safety, appears to have been among the first out of the gate toward that goal, making a low-speed crash avoidance system available with its XC60 crossover SUV. Dubbed "City Safety," Volvo's detection system uses "LIDAR" -- a cross between laser and radar -- to prevent fender benders below 9 miles per hour (14.5 kilometers per hour). It can significantly reduce the force of a crash up to 18 miles per hour (29 kilometers per hour), and Volvo says that below the 18 miles per hour (29 kilometers per hour) mark is where 75 percent of all accidents happen anyway [source: Ulrich].
So-called adaptive cruise control systems use laser or radar to maintain a set distance from other vehicles on the highway. Available today on more upscale brands including Audi, BMW, Lexus and Mercedes, it's just a matter of time before this technology migrates to within reach of drivers with smaller budgets [source: Carley].
Weight plays a big role in both crashes and fuel efficiency. To find out how automakers are putting their cars on a high-fiber diet to make them lose weight, head over to the next page.