Remembering what you've learned from the previous page, if you were to design a car to be the most fuel-efficient vehicle possible, yet still practical for everyday driving, where would you start?
The chassis might be a good place to begin. The steel frame of a standard car is quite heavy. It's also very strong, so if you want to make it lighter, you'll need to find something that can withstand the stresses of carrying heavy loads and retain the ability to absorb impacts to protect the occupants. Some automakers have already experimented with higher-quality steel, which is stronger than regular steel, allowing less of it to be used [source: USA TODAY]. But if we really want to slash the pounds, we need to look at carbon fiber. When it's properly prepared, carbon fiber is 10 times as strong as steel and weighs much less. Replacing all the steel in a car with carbon fiber can reduce the weight by up to 40 percent [source: Green Car Congress].
The vehicle's body is another area where considerable improvements can be made. The shape of the car should be tested in a wind tunnel to make sure it has the optimum aerodynamic shape. Anything that sticks out from the surface of the vehicle should be streamlined, such as side mirrors, door handles and even vehicle badging. The body should be made out of strong, yet lightweight, carbon fiber as well.
When it comes to the vehicle's power plant -- the engine -- you'll have to make some choices. There are several ways to power the car that are better than internal combustion engines, but the one you choose will largely depend on the technology that matures fastest. Hydrogen fuel cells only emit water, and they could be efficient if a clean and green method of producing hydrogen is found. Electric motors that run on batteries and plug into wall outlets are technically the most cost-effective once you do the math of converting watt-hours per mile (watt-hours per kilometer) to miles per gallon (kilometers per liter) [source: Hypercars]. That's especially true if you charge at off-peak times and have access to clean electricity, such as wind or hydro power. Sometimes you might want a little extra range or more power than an electric motor can provide, so it might be a good idea to use a very efficient combustion engine. An aluminum block will keep the weight low, and you could probably even get by with three cylinders considering how light the car is.
The interior is one area of the vehicle often overlooked in weight reduction. There are a lot of opportunities for weight loss here. For example, you can avoid heavy seat frames by making the seats out of carbon fiber and even integrating them into the chassis. A few padded areas will make them snug and comfortable, even without excess padding, foam and upholstery. You can cut back on the carpeting, too. A small compressor will run the modest air conditioning unit, but it will keep the car very cool because the roof is insulated and the windows are double-paned. There's no sunroof -- not only would it let in too much summer heat, but sunroofs actually add weight to a vehicle, and reduce chassis stiffness. We'll want to listen to music while we drive, but we don't need a huge amplifier or thunderous speakers. A modest sound system will save weight and still sound great.
Of course, you'll also want to remember to use low-rolling-resistance tires which allow the car move along easily without sacrificing traction. The sidewalls of these tires are designed to be very stiff, so they won't flex and waste energy -- a feature that improves handling, too. The tires should also use run flat technology so you won't need to carry the extra weight of a spare tire or even a heavy vehicle jack.
There you have it -- you've just designed our own hypercar. Next, let's take a look at hypercars that already exist.