Question: How do you know when a vehicle segment has peaked and is starting to fade?

Answer: When GM gets into it.

That joke still gets a big laugh in some automotive circles, but it may stop being funny if General Motors Corp.'s new Fast Vehicle Development Program hits its stride.

The world's largest automaker says it has slashed its new vehicle development time by more than 18 months since 1996, and cut $1 billion worth of costs out of the process to boot. More than 20 vehicle design programs now are running on a 24-month schedule, GM says, and several are expected to be completed in just 18 months.

That doesn't mean GM - or any other carmaker for that matter - can design, engineer and manufacture a completely new, high-volume car or truck in less than two years. According to most currently accepted standards, it means that an automaker's first dealership-ready vehicle can roll off the line 24 months after the final design has been approved and frozen. Not a big deal to a layperson, perhaps, but it's a stunning achievement to those who know that not long ago the process took five years.

Even more impressive from an engineering design perspective is the fact that GM has implemented one common, global, computer-aided-design system throughout the company and its subsidiaries in just four years. That's a Herculean task, considering GM once used as many as 26 different CAD (computer-aided design) systems - and it has more than 15,000 design engineers working in 13 design centers around the world. GM says it's one of the fastest transitions ever in the industry.

The Unigraphics system links design and engineering computer tools with an information system that is Internet-based. "It enables our employees to communicate with each other, share work and leverage best practices and talent without the constraints of geography or time of day," says Jay Wetzel, vice president and general manager for GM's Technical Centers.

Surprisingly, GM also is open about the suppliers it worked with to make the transition. Hewlett-Packard is credited with designing the infrastructure and systems integration. Wall Street darling Cisco Systems did the internal networking, and AT&T provides the global wide area network.

Ford Motor Co. also is in the process of creating a global CAD system as well - under the catchy name "C3P." The acronym combines the three "Cs" of computer-aided design, computer-aided manufacturing and computer-aided engineering (CAD/CAM/CAE) with yet another acronym: product information management (PIM).

Like GM's system, C3P is designed to offer a new easy-to-use technology in a single system for designing, simulating, testing, and optimizing vehicle manufacturing electronically, long before physical prototypes are constructed.

"Our goal is a single data model accessible from anywhere in the world, with geometric, design and business information easily accessible through a Web browser. This will make accurate, up-to-date information available to people such as designers, analysts, and production planners as well as parts, service and dealers," says a Ford spokesman.

First implemented in 1995, C3P was billed by Ford as "the largest computer-based technology transformation in history," but it is phasing in the new Structural Dynamics Research Corp. (SDRC) system more gradually than GM is with Unigraphics.

Although Ford has touted C3P highly within the industry, and DaimlerChrysler Corp. even more publicly has bragged about its computer engineering prowess with glitzy television ads, GM - until recently - has been happy to work behind the scenes.

Now it's quietly trying to publicize some of its achievements, but without revealing too much. In an interview, Kirk Gutmann, GM's process information officer for product development, is reluctant to reveal which of the automaker's new vehicles are being developed on the new, shortened schedules. After a good bit of prodding, another GM spokesman says the new Pontiac Aztek and Buick Rendezvous crossover vehicles are among the 20 new products being developed in two years or less.

Analysts aren't ready to start doing backflips over that news. They want to know what other programs are on the new shortened schedules. Two years isn't shabby for the new crossovers, says one, but he's not overly impressed because they are based on an already well-established platform: GM's front-drive minivans.

Nevertheless, faster "art-to-part" times are definitely good news for GM, which so often is criticized for showing up just when the party is ending.

Most recently, GM's Cadillac Div. was savaged for being too slow to introduce a new product in the extremely lucrative luxury sport/utility market. The Cadillac Escalade SUV arrived late in 1998, a year after Ford Motor Co.'s Lincoln Navigator and other competitors were reaping huge profits.

What's more, when the Escalade did show up it was a weak execution: little more than a warmed over clone of GMC's Yukon Denali. Cadillac also has been thumped for showing off its sexy Evoq roadster and then not being able to bring it to market until 2002.

But GM now seems to be at least in the same league as competitors Ford and DaimlerChrysler - and actually may be ahead in some implementation phases. That could translate into a big shot in the arm for GM down the road as it struggles to shore up its sagging market share in the U.S. and overseas.

Thanks to the popularity of vehicle leasing and the fast pace of the growing New Economy, consumer tastes are more fickle and changing faster than ever. That makes it even more crucial for automakers to spot and react quickly to new market trends and demands.

Faster product development allows automakers to be first with a hot new roadster or crossover vehicle, and it eliminates redundancies and contributes higher quality and more efficient plant startups.

A recent University of Michigan Delphi survey of North American industry executives and engineers says Japanese automakers still are considered the fastest at bringing new high-volume vehicles to market. European makers are the slowest, and Detroit-based automakers are somewhere in-between.

In the 1950s, U.S. automakers routinely developed new vehicles in two years or less. GM developed the 1955 Chevrolet Bel Air and a pickup truck - plus two new engines and transmissions for each - in 22 months.

Those were the days of few federal regulations, smaller corporate bureaucracies and simpler cars. As life grew more complicated for automakers with new safety, emissions and other regulations, product development times grew to a debilitating five years or more.

Now most automakers are looking to develop new products even faster than they did in the 1950s. Some are even pushing to develop new vehicles in just 12 months.

GM's Mr. Gutmann says getting below 18 months isn't currently a high priority. But GM is continuing to investigate new uses for the Internet and to invest in millions of dollars worth of expensive high-tech visualization gadgetry that enables vast amounts of design data to be moved around with ease.

Mr. Gutmann says GM is doing more and more work with "lightweight" math models that are easier to shoot back and forth over the Internet, and using them to extend the exchange of data further down the supplier food chain.

GM also is doing a lot with virtual reality visualization tools that enable designers, engineers and top executives, with the aid of special glasses and projectors, to "see" full-size three-dimensional representations of new products that are only computer renderings. The technology is exotic and expensive but still far less expensive and time consuming than building clay models and physical prototypes.

GM remains less gung-ho than Ford in developing technology that will project full-size holographic images of new vehicles without the aid of special glasses, but GM's Mr. Gutmann says visualization is a crucial part of the automaker's product-development process. "As math becomes the master, we still need to see, to have a robust visualization strategy," he says.