Already, the strike has transformed some habits.
This morning, software developer Gary Stewart, 39, got one of the last spots in a long line of bike racks outside the Comcast Center.
No, his regular means of transport - a regional rail train from Lansdowne - wasn't shut down, the way buses, subways and trolleys were.
The problem: The waiting became intolerable.
"Yesterday, I couldn't get on three different trains," he said, explaining they were filled farther up the line.
The third train, which usually has four cars, had only two, "which is absolutely ridiculous," he said.
So he pedaled nearly seven miles this morning.
"If it rains, I will probably work at home," he added.
Philly's usually a bike-friendly city, said Stephanie Singer, 28, a marketing strategist at BAJ Design, who almost always rides her bike about a mile and a half to work.
She observed, however, that because of the strike, not only was car traffic up, but courtesy was down, as harried drivers ran more yellow lights and blocked bike lanes.
Yesterday, heading home with five other bikers, they got stuck behind a car that hogged the bike lane for an entire block, she said.
Safety's a big worry for cyclists, she said.
"I'm a huge fan of helmets," she added, recalling how a cycling friend got killed by a bus a couple of years ago.
The visibility of helmets helps make driver more conscious of bikers, she said.
Nearby, at the intersection of 17th Street and JFK Boulevard, a cab swerved toward the curb, oblivious to an oncoming biker, who jammed on his brakes - then chose to go around on the sidewalk.
Several other bikers ignored one-way signs to cross the boulevard in the wrong direction.
A man on a moped stopped at the light - carrying big clear bags of what looked like laundry on the back - but a cyclist, after scooting between cars, continued right through the red light.
All this took place within about 10 minutes.
In Philadelphia, only children 12 and under can legally ride on a sidewalk.
"Generally, bicycles on the sidewalk is probably the top pedestrian complaint," said John Boyle, advocacy director of the Bicycle Coalition of Greater Philadelphia, which yesterday set up a bike corral and assistance center at City Hall's northwest plaza.
"Bicycles are vehicles, so all the same traffic laws that apply to motor vehicles apply to bicycles," said Sarah Clark Stuart, the coalition's campaign director. "They have the same rights, but they also have the same responsibilities."
Drivers are supposed to stay out of bike lanes, except when carefully drifting over to set up for turn, Boyle said.
On roads that don't have bike lanes, cyclists are supposed to keep to the right, if it's safe and practical, under state law, he said.
From 8 a.m. to 6 p.m. daily during the strike, the coalition will be dispensing information and advice at the City Hall bike corral. The two people usually on duty might add air to tires, but they're not there to do significant repairs, Boyle said.
The coalition has also been counting bike traffic, to see how the increase compares to the 2005 SEPTA strike, when bike-riding soared 90 percent.
The initial tabulations should be available tomorrow, he said.
At the same plaza this afternoon, CityRyde was letting the curious take bikes out for a spin.
The outfit hopes that a study backed by the mayor will lead to a "request for proposal" - asking for bids to build such bike-sharing system, said CEO Ericson.
Washington already has such a sharing system, and Boston is also moving forward, he said. Members typically pay a yearly fee of about $40.
"In Philadelphia we're anticipating about 1,000 bikes at about 200 stations, and these would be about three or four blocks apart," he said.
Besides showing people "there are other options out there," today's demo of the idea was timed "to help push it along in the City Hall," Ericson said.
By the end of the year, a test station could be in operation across from Love Park, he said.
Contact staff writer Peter Mucha at 215-854-4342 or firstname.lastname@example.org.