I WAS HAPPY as a chipmunk on a log to read that in recent months bicycle-riding on Spruce and Pine had nearly doubled and riding on the sidewalk had dropped by up to 70 percent on those two streets.

I felt a weird thrill when I read that in a letter to the editor from Sarah Clark Stuart, campaign director of the Bicycle Coalition of Greater Philadelphia.

The stats for bike-riding almost doubling came from a study last year made by coalition volunteers, counting bicycles at four intersections on Pine and Spruce. The increase is believable, what with two traffic lanes surrendered to pedal-pushers. (Actual numbers are less impressive. The biggest jump, at 22nd and Spruce, had bikes going from 53 to 103 per hour. The smallest, at 8th and Pine, went from 23 to 51. Not exactly Amsterdam.)

When I dug into the numbers, the percentage decrease looked like an increase in the number of illegal sidewalk-riding bikes.

I called Stuart, who said I got it wrong. They counted bikes in the morning and afternoon before the bike lane, but made two counts, morning and afternoon, after the bike lanes.

Is that kosher? I showed the coalition's paperwork to Dr. Marc Sobel, who teaches statistics at Temple University's Fox School of Business. The coalition methodology is not valid, he told me.

So - and I hate to bring this up during National Bike Month - those stats are no better than the November report by the Streets Department that mysteriously failed to count at the two biggest intersections - Broad at Pine and Broad at Spruce - where you would expect the worst problems. Deputy Mayor Rina Cutler gleefully accepted the flawed report anyway and gushed that she wants more bike lanes (to accommodate the 1.2 percent of Philadelphians who commute by bike).

Cutler's glee was no surprise because the city was laying bike plans even before the flawed study with the predictable outcome. I'll get to that in a moment.

First, let's say the estimate of a 70 percent decrease (the range was actually 41-75 percent) in sidewalk-riding was right. What does it say about the 30 percent who persist on sidewalk-riding law-breaking despite having whole car lanes for their exclusive use, I asked Stuart?

After a very long pause, and a whispered consultation with someone nearby, Stuart said it shows a need for more education and enforcement.

I agree. Too bad, as I've shown in past columns, there is almost no enforcement.

So we have one deeply flawed study, another with invalid methodology. Will that stop the bike-lane stampede? Nope, because the Philadelphia City Planning Commission was working on a bicycle and pedestrian master plan even before the fishy reports.

Get ready for gridlock!

Phase One focuses on Center City, North, Northwest and South Philadelphia, where 54 miles of new bike-only lanes would be added. Streets that could lose a whole car lane include portions of 2nd, 3rd, 9th, 10th, 13th, 18th, 20th and 21st, plus Market and JFK.

In addition, there are 122 miles of proposed "marked shared lanes," where bikes can ride in the middle of a lane, slowing cars to bike speed. Streets include - to name a few - Race, Arch, Chestnut, Broad, Cecil B. Moore, Diamond, Glenwood Avenue, Washington Lane, E. Johnson, E. and W. Mount Airy, Manayunk and Ridge.

Then there are 32 miles of "bike-friendly streets," with speed humps for cars, with bikes - unlicensed, uninsured, unregulated - allowed to take the middle of a lane. In South Philly, 13th, 15th, Wharton and Federal will get the treatment, as will Poplar in North Philly and Carpenter/E. Gorgas in Mount Airy. An unstated goal: Cut speeds to around 15 mph, which is 10 below the posted limit.

To mark "Bike to Work Day" Friday, Mayor Nutter biked "to work" - from the Art Museum. It would have been more than empty symbolism had he biked from his home in Wynnefield, just seven miles from City Hall. But the mayor drives daily in his Chevy Tahoe hybrid SUV (at speeds far greater than 15 mph) No Lance Armstrong, he.

For the reality-challenged, I am not anti-bike. I am pro-bike, I am pro-mass transit. I don't own a car, but I oppose turning over hundreds of miles of city streets to a tiny minority, bikes, that will never become a significant alternative to private cars. And it's even worse when the stats come from books cooked like a Christmas goose.

Planning Commission Executive Director Alan Greenberger tells me that nothing has been codified, but I see the drift as clearly as a Gulf of Mexico oil slick.

Turning over more lanes to bikes - fair-weather friends - will create year-round, undreamed-of traffic snarls. Is the city plan intended to punish drivers into abandoning their cars?

That won't happen in meaningful numbers, but road rage might. I see it building as drivers fume waiting for as many as four light changes to get across Broad. I already see cars cheating and unlawfully running in the bike lane.

The planning commission's goal is to get bike commuters up to 5 percent by 2020. Wow! - 10 years to achieve a whopping 5 percent. For that, the city will infuriate and bog down the 85 percent who commute by car - adding to travel time and fuel emissions.

Beautiful.

E-mail stubyko@phillynews.com or call 215-854-5977. For recent columns: