There is paradox in NBC’s analysis of its ratings for Saturday night’s Pepsi 400.

The numbers are dumbfounding and augur well for the upward spiral of NASCAR popularity to continue — probably even to accelerate.

But at the same time, they are sobering, bordering on frightening. This is an explosion on, or over, the edge of control.

The race telecast simply blew away all other prime-time programming on all other networks. It doubled the second-best performing network, CBS, in the key demographic groups nearly all advertisers seek — the 18-49 and 25-54 age groups. The same was true in the key sports demographic, which is, simply, adult males.

In the old days of three-network television, a 6.0 rating and a 13 share wouldn’t have made anybody do cartwheels in Rockefeller Center. But in today’s world of hundreds of channels at war for fragments of points, a 6.0 brings out the champagne.

Thirteen percent of all television sets that were turned on Saturday evening, or 20 million people, were tuned to a sport that once was overjoyed to get five minutes of videotape on ABC’s Wide World of Sports every few months.

And that was barely half the audience NASCAR’s showcase event, the Daytona 500, drew on Fox back in February.

The boom is by no means limited to NASCAR’s traditional turf, the Southeast.

Chicago had the highest single-market increase, 38 percent, in season-average ratings for NASCAR on NBC, from 2001 to last year. And Chicago’s ratings for last Saturday night (the first race for the midseason switchover from Fox to NBC) were up 21 percent over last year.

So NASCAR comes to sold-out Chicagoland Speedway for Sunday’s Tropicana 400 no longer as a venture onto foreign ground but as a publicly accepted member of the pro sports community–da Bears, da Bulls, da drivers .

In Oklahoma City, of all football-only places, NASCAR last Saturday night pulled an 8.1 rating. That means 8.1 percent of all television sets in that market were tuned to the race, a Sooner-booming 76 percent over last year, more than anyone at NASCAR or the networks could have foreseen.

Out the window goes a rule of thumb I’ve used for writing NASCAR stories for at least 20 years. “Don’t get too technical; write it so even a soccer mom in Connecticut can understand it,” I’ve advised rookie reporters.

Now that must change: “Don’t get so technical it takes a soccer mom in Connecticut to understand it,” I must say. Hartford is watching NASCAR 57 percent more than it did last year.

What do the blackjack dealers, croupiers and pit bosses of Las Vegas do for leisure-time excitement? They must be watching the gamblingest homeboy they’ve got (on the racetracks, at least), Kurt Busch. Ratings are up 58 percent over last year.

In Indianapolis, where once any given local would smirk and say, “Real race cars don’t have fenders,” the prime-time taxicab race drew a phenomenal 12.6 rating (basketball-size numbers there), up 46 percent over last year.

So, in the immortal words of Austin Powers, “What does it all mean, Basil?”

For openers, it means it no longer matters that NASCAR still trails one league, the NFL, in gross viewer numbers. The only purpose of ratings in the first place is to strengthen the advertising sales pitch to corporations.

The NFL’s supremacy may erode anyway, but even if it doesn’t, NASCAR will win the real prize, the money.

Warren Sapp (who, by the way, was in mouth-running heaven at Daytona on Saturday night, awestruck by NASCAR) doesn’t wear a DuPont-colored jersey, nor try to stick his helmet right in Rich Gannon’s “Home Depot” logo.

Combine the rolling billboards with the fact that NASCAR fans are long proven, by scientific surveys, to be the most brand-loyal fans in all of sports–and now throw those soaring ratings into the mix, and it’s a no-brainer for cost-effectiveness among advertisers.

But that brings us to the bad news, the scary part.

I never need Nielsen numbers to know a race has been heavily watched on television. I can tell by the e-mails from fans, outraged at the saturation of telecasts with commercials.

This week, the traditional fans are furious out there. Some counted a commercial every seven minutes. (You don’t notice it when you’re at the track because there are no TV timeouts.) They want to watch Dale Earnhardt Jr. racing–not driving some actor home from a movie-set bar in a Budweiser commercial.

So here is the cataclysmic news I must report: It can, and will, only get worse.

The networks paid $2.4 billion for the current TV contract–a few hundred million more, if you count Fox’s overall investment. They’ve had ad revenue shortfalls as high as $100 million per season so far.

The advertising and ratings upswing should cure that, with a bonus: Nextel, in replacing Winston as series sponsor next year, will dump an additional $50 million annually into the advertising pool.

So the money’s taken care of. (NASCAR always sees to that.) But the fans aren’t. (NASCAR used to see to that.)

NASCAR has always, above all else, been addicted to money. Now the habit rages beyond control, insatiable, all-consuming. For every one of you who loved racing for the sport of it, and won’t put up with this much longer, there’s a gazillion tattooed teenagers waiting to take your place, certain for the moment that NASCAR rocks.

So if you don’t like it, you can just sit and suffer.

Which is about what NASCAR telecasts are causing traditional fans to do.