The technological innovations in the auto industry go deeper than the tales of cast iron, steel and rubber. It's about people, intuition and some good-ol' engineering.

America's early automobiles were rudimentary, at best, but they were easy on the spine and you didn't need a whip, as Charles E. Duryea once pointed out.

Today's vehicles are easy on the entire body. From coutoured seats and seat belts, self-starters and air bags to automatic transmissions, padded dashboards and safety glass, the number of technological advances made in 100 years is mindboggling. Here we've touched on some of the early ones that helped put the common man -- and woman -- behind the wheel.

Stopping gets attention

To the fledgling automotive industry, the overwhelming priority was to simply get moving. So for quite a while, no one was too worried about stopping.

Early braking systems were crude friction devices that operated on one wheel or on the drive itself. The first 4-wheel brake system appeared in 1910, but brakes at every corner were far from standard.

In 1921, Duesenberg produced the industry's first true hydraulically assisted 4-wheel brake system. The impact was tremendous; the wonder of hydraulics delivered braking force formerly impossible to develop.

But Dueseys were expensive. Chrysler Corp. adopted 4-wheel hydraulic brakes in 1924, in what represented "affordable" state-of-the-art braking until Chryser offered hydraulically assisted 4-wheel disc brakes on the 1950 Crown Imperial.

Considerable argument ensues over who was first with refinements such as true power assistance and self-adjusting features. But what cannot be overstressed is the quantum leap even early drum brakes provided.

Crank it up

It wasn't the hassle of standing in the rain or snow to hand crank an engine that set that automotive practice on a course of extinction and ushered in the electric self-starter. It was a broken jaw.

While there were other early self-starters, such as the compressed air system one French automaker offered, many were unreliable, and larger engines still had to be hand-cranked. The process was as hard as it was dangerous.

A friend of Cadillac owner Henry Leland was cranking a motor when the lever struck and broke his jaw. While details of that painful day have long since faded, its outcome has not. The accident got the wheels in Charles F. Kettering's head working, and the owner of Dayton Engineering Laboratories Company, or Delco, quickly sketched a relay-controlled system.

It was between 1910 and 1912 that Mr. Kettering found a solution to the problem. Using a battery, single-coil ignition, electric self-starter/generator, and electric lighting, he was able to perfect a unified automotive electrical system.

Leland provided the foot-operated starter standard on the 1912 Cadillac. Suddenly, the automobile became practical for millions of new buyers, and led to a huge increase in the number of female motorists. And Mr. Kettering's system paved the way for automotive electrical systems for decades to come. The foot-operated starter was followed by a button and then the ignition-starter key system of today, which was first introduced in 1949 by Chrysler.

American icon

If there is any one automotive item that best captures America's attitude it's probably the V-8. It is big, bad and it is powerful.

While the V-8's roots can be traced back to as early as the mid-19th Century, it is Henry Ford who made it affordable. Historians say Ford's low-cost 1932 V-8 ranks up there with his Model T, the assembly line and $5 day as among his great contributions to the automotive industry.

The idea of arranging cylinders in a "V" formation was viewed advantageous by steam-engine designers as early as the mid-19th Century. Pistons in a "V" rather than in a line were more compact and provided a shorter, sturdier crankshaft.

V-type engines were in some of the earliest autos, including a V-2 and V-4. Frenchman de Didion-Bouton showed a V-8, but it wasn't until 1915 that the V-8 actually made it into a production car: the Cadillac Type 51. Cadillac augmented that engine with V-12s and V-16s in the '30s. After 1940, the V-8 remained Cadillac's only engine until 1981 when it added a V-6 because of fuel economy concerns.

Ford began work on a V-8 after arch-rival Chevrolet stung Henry by coming out with a 6-cyl. in 1929. A year earlier Mr. Ford introduced his Model A, but it came with a 4-cyl., just like his Model T. Chevy's powerplant was smoother and more powerful than the Model A.

What made Mr. Ford's approach so novel was he intended to make a low-priced V-8 with a one-piece cylinder block. Up until then, V-8s were multiple pieces bolted together, which made them expensive and time-consuming to produce.

Bob Casey, curator of transportation at Henry Ford Museum, says Ford advanced the casting process "significantly."

In April 1932, Mr. Ford introduced his 221-cubic-inch, side-valve V-8 that produced 65 hp, five more than Chevy's six-cyl., and a top speed of more than 80 mph. The horsepower race was on.

Ford dominated auto racing for many years with the V-8, and it became popularized by gangsters and those whose job it was to pursue them.

Ford replaced the flathead V-8 with an overhead-valve V-8 in 1954, but a year later Chevy stung Ford again.

Chevy launched its own V-8 in 1955. Chevy may have managed to beat Ford in the sales race, but with just a 6-cyl., the automaker up to then had lacked the power or pizzazz to attract the younger buyer. That was until ED Cole came along. Mr. Cole was chief engineer (he later became Chevy's general manager and later president of GM) and helped develop the heart-beat of the new Chevy: its stunning overhead valve V-8.

The Chevy V-8 was able to grab Ford's V-8 leadership.

For 1957, Chevy bored the cylinders out 3 mm to increase displacement to 283 cubic inches. It was in this size that the small-block Chevy, as it was soon known, earned its spot in American engine history.

The V-8 became the standard of the American automotive industry for more than 40 years, until the fuel crises of the 1970s dethroned it. Today's throbbing heart is run by multivalve, overhead cam engines and they're faster than ever.

Automatic transmissions

There were many slips and false starts on the road to developing an automatic transmission to replace those brutal pedal clutches and clanking lever-shifted gearboxes.

There were flashes of brilliance along the way, like friction-drive and fluid-drive transmissions. But it wasn't until 1940 that the automatic transmission moved into any meaningful production and helped open up driving to a large segment of the population who otherwise wouldn't have slid behind the wheel.

Most of the pioneering in the automatic transmission known today can be traced to the U.S. Perhaps the first stab at an automatic was seen in the American Carter-car of 1908, which used a friction-drive system. It wasn't until the 1940 model year when GM unveiled the Hydra-matic on the Oldsmobile that the automatic transmission became a market-place success.

Cadillac adopted the automatic the following year, and after World War II, other popped up, including the Ford-O-Matic, Plymouth's Powerflight, and Buick's Dynaflow.

"When word got out they worked well, people bought them like crazy," says Randy Mason, an automotive history consultant. "It was a real breakthrough."

Fuel injection

Countless component and systems refinements were vital to bringing mobility to the masses. Once the internal combustion engine was made to function with degree of reliability, attention naturally shifted to other components.

It's easy to understand, then, the distractions that led to something of a "hands-off" attitude toward engine carburetion. It worked relatively efficiently: air and fuel went in, work was produced.

Margaret E. Nordquist, manager of public relations and information for the Robert Bosch Corp., traces early fuel-injection designs to 1898; the Wright brothers' first airplane employed a rudimentary gravity-feed fuel-injection setup.

But it was military work that drove development. The environmental and dynamic requirements for aircraft engines are brutal, and fuel injection was seen as a way to imbue an aero engine with the crucial reliability vital in all aircraft components.

Although a 1954 Mercedes-Benz 300 SL fitted with Bosch fuel injection was the first production auto with the highly efficient system, Chevrolet adopted fuel injection three years later for its "fuelie" Corvette V-8.

Pulling beats pushing

From the onset, it seemed natural to situate the vehicle's engine at the front with a connecting driveshaft down the center to drive the rear wheels.

But some -- among them the ingenious Andre Citroen -- believed it made more sense to locate the driven wheels' force under the major mass, the engine, providing better traction and safer handling.

Cord adopted front-wheel drive in 1929 and it was to prove a hallmark of many classic Cord designs. But few automakers acknowledged Cord's prescience, and the front-engine, rear-drive vehicle layout dominated until well into the 1950s.

Perhaps recognizing the advantages offered by Britain's transverse-engined front-drive Morris Minor, GM used front-drive in the design of its 1966 Toronado. The Toronado, by today's standards, was a huge vehicle, but GM reckoned it could free up even more interior space by packaging the drive in front.

Toronado was mildly successful, but it took Chrysler to show the U.S. industry the light. The transverse-engined Omni/Horizon yanked the Big Three into competitiveness with Japanese imports that had dominated the small-car market.

The sudden shift to front-drive came at a time when the industry desperately needed a cure for the difficulties it faced in achieving newly mandated fuel economy and emissions standards. The tight packaging of the drivetrain meant smaller vehicles could devote more of their overall size to passenger space -- a detail Cord had unearthed 50 years earlier.

Electronics' impact

Of all the technology during the auto industry's 100-year history, electronics has the shortest time frame to address and probably the greatest impact.

If you take Robert Bosch's low-voltage magneto, Charles F. Kettering's electric starter, electric vehicle lighting and Delco's first in-dash radio of 1936 for granted, automotive electronics were born in the '50s with the dawn of transistors and integrated circuits (ICs).

The 1955 Chevrolet Corvette offered the first Delco transistorized car radio. But integrated circuits wouldn't make major inroads for several years. After they became cost-effective, however, the industry never looked back.

Not all electronic ideas made it into production. A steering column-mounted radio and a dash-mounted 45-rpm record player never left Delco R&D. And removable radios such as Oldmobiles' 1957 TranSportable and '70s fads of 8-Track tape players and in-dash CB radios also had short lives.

Vehicle manufacturers had to throw caution to the wind in the '70s when the federal government forced them to reduce tailpipe emissions. After all the mechanical adjustments were exhausted, electronics provided the solution in 1978.

And safety systems of today would not exist without electronics. Antilock brakes (ABS) and air bags are now standard equipment almost across-the-board.

GM introduced multiplexing in 1979 to provide diagnostic access to engine-control electronics. By 1999 every new GM vehicle that takes to the road will have the engine control.

As automakers try to cram more and more features into a continually shrinking space underhood or underdash, miniaturization is the key to electronics growth.

Coupling miniaturization techniques with heat-resisstant ceramic circuit boards will allow ECUs to be placed closer to the engine and handle even more functions.

The vehicle of the future will offer collision warning, adaptive cruise control, night vision, occupant sensing and vehicle-to-roadside communication. But its true significance won't be in its individual features, it's the integration of them all.

Industry pioneers such as Henry Ford might not have been able to look 100 years into the future and see computer-controlled engine management and safety systems, but electronics pioneers could.

One guru predicts a car will someday leave Michigan on a dedicated wired lane of highway, punch in a Florida destination and automatically take passengers to the Sunshine State at 130 mph (209 km/h) in about half a day.

That's not going to happen in the next 20 years, but that's the direction we're heading.

Baby, light my fire

Simply holding and looking at a spark plug, it's easy not to feel overwhelmed. But that humble little item, complete with its steel jacket surrounding an insulator, is the keeper of the flame.

It is an item that has been around in different shapes and sizes since 1860, but it wasn't until much later that a reliable spark plug could be made.

The credit for that goes to Albert Champion, a European bicycle racer who moved to Boston in 1899. Champion's decision to make his own plug began after he was unable to find a decent replacement plug for his motorcycle.

But after founding the Champion Co. and moving it to Dayton, OH, he ran into disagreements with his financial backers, who exited and created their own company, keeping the Champion name.

In 1908, Champion resurfaced in Flint and hooked up with GM's Billy C. Durant, who founded Champion Ignition Co. The company became AC Spark Plug in 1922.

Like other plug makers of its time, Champion was faced with designing a plug that could withstand the higher compression and hotter temperatures of the new, more powerful engines. The powdery conductive material stuffed into the core to hold the electrode in place loosened with engine use, which allowed gases to escape.

The search for a strong, economically feasible plug continued into the late 1930s. It was then that AC engineers found a solution. Using a mixture of powdered copper and glass in the core and then melting it with furnace heat, engineers were able to create a glassy matrix that sealed the core, bonded the core to insulator and conducted electricity from post to electrode.

Engineers also solved the problem of finding an insulator to replace the traditional plastic-clay type compositions that couldn't hold up in the increasingly sophisticated engines by using aluminum oxide. The glass-metal seal and aluminum oxide insulator concept was patented in 1941 and is still being used today.