LOS ANGELES - Our German chaperone is nervous. Sitting in the passenger seat of Audi's hand-built Prologue concept car that debuted at the recent LA Auto Show as we cruise through Beverly Hills, he eyes the police surrounding us.

"Slowly, slower," he says politely as he squints into the tiny side-view mirror. We ease off the 605-horsepower throttle a bit, as the motorcycle cop behind us weaves.

It's not the police our copilot is concerned about; they're part of a mini motorcade keeping the Audi safe from errant drivers. He's worried about the Prologue itself: a prototype that cost Audi between $4 million and $6 million to build.

Hand-built over seven weeks this fall, the glimmering full-size coupe is a rolling exhibition of Audi's future. The design elements from the car's interior and exterior will be incorporated into the next generation of Audi's large cars, starting with the new A8 sedan due for sale in 2017.

The midsize A6 and A7 will follow shortly after that. Audi is also expected to build a coupe very similar to this Prologue. Based on the A8, the car probably will be the first car to bear the A9 name in Audi's history, and will take Mercedes-Benz's S-class Coupe head-on.

This concept car, according to the company, incorporates 80 percent to 90 percent of the production car's design cues, inside and out.

Key among the exterior cues is a massive flat grille that spans nearly the entire width of the car's nose. It is highlighted by six horizontal chrome bars and Audi's four-rings logo prominently displayed in the middle. Thin trapezoidal headlights squint out from either side of it.

The coupe's roofline descends slowly toward the rear of the car, leaving almost no flat trunk lid. This makes Prologue's silhouette imposing and dramatic, and looking a smidge heavy.

At the back, LED taillights are horizontally oriented, including a thin strip of lights running the width of the back end. The taillights also have a sculpted three-dimensionality to them that's hard to show in pictures.

The overall look of the Prologue is less revolutionary and more of a healthy evolution. True to its production intent, the coupe looks at home on L.A.'s streets rather than looking like a Jetsons science experiment.

The Jetsons stuff is inside the car.

Using the same horizontally oriented theme as on the exterior, several touch-sensitive screens stretch across the dashboard for the driver and passenger.

Audi also worked with Samsung to develop a cutting-edge OLED flexible glass screen that curves out of the center console just ahead of the shifter. Flexible display screens like this are at the infancy of their development, though manufacturers like LG and Samsung hope to have production screens on the market around the same time as Audi's next A8 in 2017. They'll be expensive.

The concept is also pricey thanks to the carbon-fiber body panels, the aluminum trim inside and out, and the wood and leather throughout the interior. It's like a couture dress: a one-off piece made, finished, and assembled by hand without the economies of scale to drive the price down.

It took a team of 20 people seven weeks working round the clock to build, Audi said. The chassis underneath is a shortened version of what's on the next-generation A8. To power the thing, Audi grabbed a 4.0-liter twin-turbocharged V-8 out of its RS7 and kicked power up a notch. It now cranks out 605 horsepower and 553 pound-feet of torque.

The drive is more a low-speed demonstration than an outright test. No one wants a crashed prototype worth millions on his resumé. And the massive amount of heat generated by the bleeding-edge electronics causes the engine's computers to retard full acceleration anyway.

But despite its kit-car status, the Prologue concept drives like the sultry coupe that it hopes to be. The suspension is cushy, the steering is direct, and the power - when it's available - is immense. The car's mass and proportions are perfect for the boulevard cruising that our 30-minute drive takes us on, weaving through and around Beverly Hills.

But it's people's reactions that bode well for this coupe's future. The police escort almost seems unnecessary; this car stops traffic on its own. L.A. may be a disenchanted audience for new or rare cars, but the Audi Prologue grabs attention - cellphones, stares, pointing - easily.

As our escorts slow to a crawl waiting for an intersection to clear, two men who look like potential A9 owners notice the car and walk up to it, clearly trying to figure out what they are seeing. One whips out his iPhone to snap a picture of the interior.

"What kind of Audi is this?" his friend asks. Our chaperone smiles as the motorcade starts moving again, and says cryptically out the window, "The future kind."