Envisioning the car of the future is a tall order. But sometimes the best way to see where we're going is knowing where we've been. A look at past innovations is a good place to begin.

The top car innovations of the past include air bags, safety belts, immobilizers, navigation systems/GPS, anti-lock brakes, cruise control, turbo chargers, convertibles and windshield wipers, as noted by The Star & Independent.

Undoubtedly, we could add to, strike from and modify this list, but it may be more worthwhile reading between the lines to develop a shorter list: safety, ease of operation, reliability, fuel efficiency and, well, fun.

Tomorrow's car will not necessarily be about brand-new bling and comfortable conveniences, but rather about improving on traditional technology.

Two characteristics of past car innovations could be seen as at odds: safety and fuel efficiency. (See: Is Driving Small Less Safe?)

The way to bring these two features together is through design, materials and new but cost-effective technologies. Like many innovative products, vehicles take incremental advances in related fields to transform today's designs into improved versions for tomorrow.

Fuel economy has driven exterior design changes. For years, sleek designs result from wind tunnel tests showing that the less wind resistance, the greater the fuel economy. Long gone is the boxy, sculpted look of years past. The curved-down hood to achieve minimal wind resistance forces another compression of engine block and accessory devices — alternator, radiator, AC, brake reservoir, coil, battery and more. This puts pressure on the engineer to rely on suppliers for high-quality materials that are machined to tight tolerances so that repairs will only be needed well after 100,000 miles.

For one, the engine design of the future will change.

Take as an example the work of a Massachusetts Institute of Technology (MIT) professor who is working on homogenous charge compression ignition (HCCI). "Under some conditions, it can reduce fuel consumption by 25 percent," Technology Review recently noted William Green, the chemical engineering professor at MIT, as having said. Key to this technology is reuse of heat from previous explosions along with heat resulting from fuel compression to create another explosion rather than use of a spark. Such technology would complement — rather than replace — spark-induced explosions.

And there's certainly no question that the continuation of more electronics is a trend we see increasing. "In 1980, electronic equipment made up less than 1 percent of the cost of a vehicle," according to

From the designer's viewpoint, "original equipment manufacturers (OEMs), carmakers and consumers benefit whenever hydraulic or mechanical systems are replaced by electronic systems. Electronic systems reduce cost, weight and fuel consumption by eliminating belt-driven burdens from the … engine," says EE Times. What applications will come first?

According to EE Times earlier this month:

Worldwide fitment rates for electronic stability control were projected to grow from 21 percent in 2006 to 35 percent in 2012 compounded annual growth rate (CAGR) of 12.5 percent. Brake-by-wire fitment rates were projected to grow from less than 1 percent in 2006 to 5 percent in 2012 (CAGR of 36.4 percent).

One of the challenges manufacturers face is "overcoming problems associated with the increased integration of power discretes with application-specific integrated circuits," noted according to Frost & Sullivan as published in Electronics Supply & Manufacturing. The high on-resistance interconnects and complications involved in the isolation of power cause design cycle delays, which prolongs time-to-market. "Once discrete power semiconductors resolve issues such as safety, security and telematics; driver information applications will likely grow at a startling pace."

Some standard features in the next generation of mass-market cars likely will include factory-installed GPS navigation, voice command, Bluetooth mobile communication and rear-view camera systems, as Channel News Asia recently noted. Such tech already exists in many newer models.

Moreover, a growing number of manufacturers are working on "accident-free" cars, which take evasive actions to help you avoid a crash. If (or when) this occurs, there may be greater acceptance of smaller and lighter-weight cars, driving a shift toward far greater use of advanced composites. (See: A Collision-Free Future)

But don't think of it as, "Oh no, not more wire!" Polymer optical fiber, for one, "allows for a cost-efficient way to transfer 'content' at 150 Mbps," according to The Auto Channel. And we can look for improvements in polymers, too. As microwaving to produce advanced composites makes them more cost competitive with metal components, the promise of more fuel-efficient vehicles becomes closer to reality. Stronger but lighter-weight types of steel are replacing conventional steel, too, USA Today reported last week.

Future cars will not only be lighter; they will be smaller, too — a consumer-driven trend we're already seeing.

"Buying a small, fuel-efficient car used to mean you'd be stuck with a dull vehicle. That is changing," noted Forbes in its Ten Car Design Trends to Shape the Future. "We are going to start to see a swing into micro-cars, toward much smaller, highly efficient vehicles like the Mini," BMW's Chris Chapman told Forbes in June.

The other design question that automakers face relates to fuel for propulsion systems. The current options beyond hybrids, which merely use gasoline more efficiently, are hydrogen, all electric, biofuel and combinations of these. Chances are that some of these will play different roles for different areas, at different times and for varying specific uses.

"The reason is not just for high gas mileage, but from a cultural and personal standpoint," Chapman told Forbes.

What else can we expect in and on the cars of the future? According to Forbes: higher beltlines: larger grilles; hardtop convertibles; elaborate sunroofs; headlights and taillights as "jewelry" (more complex headlight and taillight assemblies); larger wheels; and new paints (See: Gunmetal Metallic, Shifting Hues and GM's Other Color Palette Provisions).

What innovative features do you foresee in the cars and trucks of the future?

Car-Features Roundup:

What Your Car Says about You

Top 12 Greenest Vehicles

Coolest High-Tech Cars 2007

Pump-Busting Vehicles

Top 2007 Gas Guzzlers

Earlier: Features for Your Pleasure...and Yours and Yours

What Are Those Automakers Doing in There?

Resources

Top 10 Car Innovations
The Star & Independent, Oct. 2, 2007

Ten Car Design Trends to Shape the Future
by Phil Patton
Forbes, June 20, 2007

A More Efficient Engine
by Kevin Bullis
Massachusetts Institute of Technology, Aug. 3, 2007

Under the Hood: Silicon in Autos Driving Patent Plans
by John Scott-Thomas
EE Times, Sept. 24, 2007

Microcontrollers Promise to Improve Automotive Electronic Control Units
by Matthias Poppel and Markus Staeblein
EE Times, Oct. 2, 2007

Discrete Power Semis to Find More Homes in Automotive Applications
by Gina Roos
Electronics Supply & Manufacturing, Oct. 3, 2007

Automotive Technology Is Advancing Speedily
by Dominique Loh
Channel News Asia, Sept. 30, 2007

Telematics: SMSC Introduces New Technology Enabling Fast Transport of Multiple High-Definition Video and Multi-Channel Surround Sound
The Auto Channel, Oct. 4, 2007

Auto Components Lighten Up to Improve Mileage
by Chris Woodyard
USA Today, Oct. 8, 2007

Additional

Advanced Composites: The Car Is at the Crossroads
by Michael M. Brylawski and Amory B. Lovins
Hypercar

Driving the Transportation Revolution
Oak Ridge National Laboratory

Review: How Can We Outlive Our Way of Life?
by Robert Rapier
The Oil Drum, Oct. 2, 2007

How Can We Outlive Our Way of Life?
by Tad Patzek
University of California, Berkeley, Sept. 10, 2007