Today New York's first Summer Streets blocked seven miles of city road to motorized vehicles from 7 am to 1 pm.

Enough people took advantage to make Summer Streets successful, but not enough to make it as hellishly congested as a big concert or protest march, which had been our big worry. By our informal estimate, about half the participants walked and the rest biked, which must have pleased our Mayor, whose promotion of bike rentals and bike paths (and, of course, this event, which Bloomberg touted Thursday in a joint press conference with Jay-Z) are among his nicest gestures toward citizens who are not landlords.

We biked the route, which dog-legged out of Central Park at East 72nd down Park Avenue, continued down Lafayette in the Village, and discharged at the Brooklyn Bridge. The upper stretch of Park Avenue was by far the most pleasant. We've stared up at those big old neo-Georgians and office buildings a million times, but not from the middle of the street, lest we be run over. The closer you get to the Park, of course, the better they take care of the roads, which made the ride smooth going.

The most popular part of the northern leg was the passway around Grand Central, which is seldom walked by anyone not wearing a uniform. Clusters of pedestrians, sensing the rarity of the occasion ("Not seen by ordinary mortals!" cried one cyclist), lingered as if at a museum, and took pictures.

There was a series of roadside attractions well-spaced along the route. They got more rubbernecking than participants, but added a festive whiff of street-fair atmosphere, fortunately minus the scent of zeppole and funnel cake. Crunch Fitness led sweaty citizens through workout routines; a "Conductorsize" instructor passed out batons and worked his small crowd into a Lenny Bernstein frenzy of upper-body and (on crescendos) hamstring exercises. He also offered random music criticism: "Brahms and Beethoven," he announced, "could only count to five." At St. Bart's a padre wearing a button that said BUDDY stood beside a Peanuts-style "The Clergy Is In" sign and passed out free lemonade. Down by Astor Place they gave hula-hoop demonstrations.

The City DOT gave out very nice, very green bike helmets to anyone willing to sign a waiver ("I understand that the proper use of this helmet is my responsibility") and submit to a fitting. Kids and some adults wrote in chalk on the reclaimed streets. A woman sat on a Park Avenue traffic divider and quietly munched a sandwich.

We have few complaints. The downtown part of the route was narrower and much less well-paved than the uptown, and in a concession to traffic realities cars were allowed to interrupt us at the major cross-streets. Why not tell drivers to park it all over Manhattan for six hours? But that's actually a major benefit of Summer Streets: it gets you thinking about how much further the City could take it.

And it gave bikers the rare thrill of vehicular dominance on streets where they are usually the prey of cars. (A dad pedaling his kid up Lafayette looked down Prince Street at the unholy traffic snarl on Mulberry, laughed and gave a thumbs-up.) Critical Mass rides do this too, but Summer Streets, being far less raucous and rebellious, is more likely to inculcate the timid masses with brave dreams of a less car-congested city.

And we get to do it again the next two Saturdays.