ON FRIDAY THE city broke the seal on the most closely guarded secret since the Manhattan Project when it revealed where Center City bike lanes will be added - southbound 10th between Spring Garden and Lombard, and northbound 13th between South and Spring Garden.

Already clogged, after one of the two traffic lanes is surrendered to bikes, those arteries will look like those of someone who eats fettuccine Alfredo for breakfast, fried chicken for lunch and supersized Big Macs for dinner. You think Chinatown's traffic is a mess now? Just wait until late June, when the changes begin.

The city's misleading news release said the bike lanes are being added to meet "record demands," claiming that "more than 15 percent of residents in some South Philadelphia and North Philadelphia Census tracts choose to bike to work," according to 2005-09 American Community Survey data. Wow! That's huge! The most recent Census estimate of bike commuting I knew of was 1.6 percent.

Uh-oh. The city said the big numbers occurred "in some" Census tracts. What it meant was in a very few, carefully selected Census tracts.

I went to the map. The highest bike use was 17.2 percent in Census tract 127. It was one of only five tracts with double-digits. More than 240 tracts had zero bike commuters. It still ain't Amsterdam out there.

Census tract 127 is bounded by 6th, 10th, Green and Vine. It has 192 workers over age 16, and 33 of them use bikes. It may have the highest bike use in the city, but it has no community name as it overlaps Northern Liberties, Spring Garden, Callowhill and North Philly. I know! Let's call it Bike Haven!

The city calls the bike lanes a "pilot program" and will review after six months, but it's permanent, believe me, unless something goes seriously wrong.

I don't expect a Hiroshima-style explosion. I expect a slow burn as motorists are delayed after two lanes of traffic are melded into one lane in Center City, where traffic is heaviest. The city is incrementally creating the greatest remake of city streets in 100 years, yet few see what is going on. It's like putting a lobster into a pot of cool water, then turning up the heat one degree at a time. Before long, the lobster's boiled alive. Philadelphia motorists are the lobster.

Most bikers are fine, but there's a noisy lunatic fringe as impervious to facts as "birthers."

This is my opinion: Philadelphia streets are too small and clogged. Bicycling will never be a serious alternative form of transportation here. The City Planning Commission's own hope is to hike bike commuters to a stunning 5 percent by 2020. For this, they're remaking the city?

This is fact: Estimated percentage of Philadelphia bicycle commuters: 1.6 percent, with about 83 percent living within 4 miles of City Hall. There is virtually no enforcement on biking lawbreakers now. There is heavy enforcement on cars and actually twice as many tickets written to pedestrians as written to bikers.

You can't argue with the facts, and here they are:

Enforcement for 2010:

Tickets issued to motorists: 175,909.

Tickets issued to pedestrians: 89.

Tickets issued to bicyclists: 40. That's right - 4,397 car citations for every bike ticket.

Although most bikers are nice people, most are also lawbreakers: They run red lights, blow through stop signs, ride the wrong way on one-way streets, ride on sidewalks. It's all illegal, and every pedal-pusher breaks at least one of the above regularly. I've seen it, you've seen it and they admit it, when they're being honest.

The city - stop me if you've heard this one before - again promises enforcement. It has a campaign, aimed at motorists, pedestrians and bikers, called "Give respect, get respect."

But it's meaningless without enforcement. Motorists and pedestrians are rightly angered that too many bicyclists ride wild and get away with it.

I said you can't argue with the facts, but some bike-heads do. Some don't believe my numbers, which come from the Police Department, the Bicycle Coalition of Greater Philadelphia, the City Planning Commission and the census. It doesn't matter to them. The fringers are so enthralled with their "greenness," so intoxicated by their imagined moral superiority they believe that facts don't matter.

But they do, and I'll continue examining them.

Email stubyko@phillynews.com or call 215-854-5977. See Stu on Facebook. For recent columns: