02. Hybrid vehicles.  If we all lived in Utopia, then we'd probably be driving around in non-polluting, energy-efficient electric cars. (If we didn't have a transporter beam handy.)  Since we are in the real world, where even your cell phone dies after a few hours of use, we know that we can't trust our vehicles to be run by batteries.  Clever engineers have instead brought us gasoline-electric hybrids.  These have engines that are a little smaller than they should be, because in line with the gasoline engine is an electric motor that can kick in to assist acceleration.  Toyota's Prius runs only on the electric motor at low speeds to further conserve fuel, with the gasoline taking over as speeds build.  The gasoline engine does the charging of the batteries, so no plugging in is necessary.  Proponents of small, fuel-efficient diesel engines may snicker at the complexity of these gasoline-electric hybrids, but where's the fun and innovation in that?  Hybrid cars also incorporate other useful technologies, such as regenerative braking, where previously wasted energy is used to recharge the batteries.  Hybrid cars such as the midsize Prius (23.3 km/liter), Honda Civic Hybrid (21.6 km/l) and Insight (28 km/l) are among the most fuel-efficient automobiles on the market.

03. Brake by Wire.  Would you feel comfortable knowing that your brake pedal doesn't really push anything but is just a switch for the computer to activate the brakes?  Borrowing a page from the aerospace industry, Mercedes-Benz engineers have put into production a completely brake-by-wire system called Servotronic for the new SL and E-class.  Indeed, the brake pedal merely signals the computer, and the computer then actuates servomotors at each wheel to start putting pressure on the brake discs.  The response time is reportedly quicker than a conventional hydraulic system.  The computer can also detect moisture on the brake discs and lightly wipe away the water with no intervention required from the driver.  A quick release of the brake pedal also prompts a "get-ready" mode where the brake pressure lines are charged, ready for full application of braking force.  This can reduce the distance of a full emergency stop.  In practice, most publications have reported that the new system is far from smooth and feels artificial.  As with most computer-assisted devices, one or two more generations of development and it should be quite smooth as well as effective.  We will then wonder how we managed without it.