The Bloomberg administration has announced that it will create a new Midtown pedestrian mall, this one running on 34th Street, between Fifth and Sixth Avenues -- that is, between Macy's and the Empire State Building.

The plan, which would go into effect in 2012, allows for bus lanes in both directions on that block, though it remains unclear how the diverted car traffic will affect the surrounding area. City officials say the north-south pedestrian malls on Broadway in Times Square and in Herald Square have been a success.

What are benefits of its proposal for 34th Street, and what are some possible problems?

* Sam Staley, co-author of "Mobility First"
* Robert Sullivan, author, "The Thoreau You Don't Know"
* Hope Cohen, former M.T.A. official
* Paul Steely White, Transportation Alternatives
* Tom Vanderbilt, author, "Traffic: Why We Drive the Way We Do"
* Julia Vitullo-Martin, Regional Plan Association

Where Will the Traffic Go?

(Sam Staley is the director of urban and land use policy at Reason Foundation and the co-author of "Mobility First: A New Vision for Transportation in a Globally Competitive 21st Century.")

The current plan to revamp 34th Street for transit use and pedestrians is bold and innovative, but risks ignoring critical Midtown traffic circulation needs. A failure to plan adequately for crosstown travel and the non-retail and tourist-oriented commercial needs of the affected neighborhoods might reduce overall mobility.

Although just 10 percent of the traffic along 34th street is by car, this traffic meets important commercial needs. This traffic will be displaced without any obvious planning for how it can be re-routed efficiently with minimal disruption to traffic circulation.

For example, will all of the traffic emerging from the Queens-Midtown Tunnel be diverted onto 37th Street? How will travelers and commercial vehicles on the East Side gain access to points west, like the Lincoln Tunnel?

Already, crosstown traffic is a major source of congestion in Manhattan. While it's tempting to think that all roads lead to Midtown, Manhattan's travel patterns are complex and nuanced. The elimination of 34th street as a main connector between the rivers will create substantial circulation, access, and mobility challenges for the surrounding streets and neighborhoods.

The city should consider long-term enhancements to the Manhattan street system that meets these circulation needs. Among the solutions could be installing queue jumpers that funnel crosstown traffic over congested intersections at major avenues (perhaps financed and managed by electronic tolling) to speed up travel along 37th street.

An even bolder plan might include a new crosstown tunnel (also financed in part by users) linking the Queens-Midtown and Lincoln tunnels. This tunnel could include an underground interchange near a major north-south artery such as the Avenue of Americas, Fashion Avenue, or Broadway. While ambitious by U.S. standards, these types of road capacity improvements are actively being considered (and planned) in cities like Beijing and Chongqing.

New York City, with one of the densest and most vibrant downtowns, continues to lead the country in thinking outside the box. The zeal to address pedestrian and transit capacity improvements, however, shouldn't allow planners to ignore other critical aspects of the city's transportation infrastructure, including roads and automobiles.

Relieving the Sidewalk Traffic Jam
Robert Sullivan, a contributing editor at Vogue, is the author, most recently, of "The Thoreau You Don't Know.")

As far as being a pedestrian goes, Times Square is the celebrity hot spot of pedestrian-ness, while Herald Square, in contrast, is more down to earth, the place where people work and walk and shop and get to lunch, as opposed to watching jumbotrons.

Even the Empire State building is more office than observation deck, filled with the untelevised people who actually make New York exciting to see.

And if you have been on 34th Street during rush hour or lunch hour or any hour of the day, then you know that the people on foot are daring to walk in the street, since the sidewalks can't handle them anymore. The return of this public space to the public not only makes sense but is overdue.

Of course, it will be derided.

Last month, in opposing a Brooklyn bike lane that would jeopardize Park Slope parking spots. Brooklyn's borough president, Mary Markowitz, made the papers by charging that the Department of Transportation is run by a "zealot," Commissioner Jeanette Sadik-Khan, whom he called "the biggest advocate of doing everything possible to eliminate automobiles."

He later softened his remarks, but he actually had it backward: the zealotry comes in defense of assisting one or two or maybe four people in a car while holding up hundreds or thousands or people who choose not to idle in the middle of an island of people with places to go and stuff to do.

Buses Are the Answer

(Hope Cohen is associate director of Regional Plan Association's Center for Urban Innovation. She spent more than a decade at Metropolitan Transportation Authority New York City Transit, where she focused on new technologies for the city's subway and bus systems.)

The real story here is the bus plan. Thirty million dollars is an obscene price for a pedestrian plaza, but it's a bargain for what is essentially a crosstown subway line.

The 34th Street Transitway would be New York's first true Bus Rapid Transit line, going beyond the painted bus lanes and pre-boarding fare payment that sped service along Fordham Road in the Bronx. Physically separated from other traffic, the transitway would offer bus stations for fare payment and platforms to allow passengers to enter and exit low-floor buses at any door.

New Yorkers should insist that transitway buses get priority over other vehicles at traffic lights -- currently planned only "where feasible," but absolutely essential to speed our new rubber-tired subway across town. Meanwhile, electronic arrival signs are already being pilot-tested on bus shelters along 34th Street, putting this line ahead of most of its underground peers in the customer information game.

Oh and that pedestrian plaza? It's in the plan to allow the transitway to cross from the southern curb west of Sixth Avenue to the northern curb east of Fifth Avenue. So motorists can drive normally, on the righthand side of the road, eastbound from Fifth Avenue and westbound from Sixth.

Some details are questionable. Why include parking lanes where none exist now? Why put the crossover between Fifth and Sixth, rather than between Sixth and Seventh, where pedestrians already swarm into the roadbed? But the overall concept is a winner: river-to-river rapid transit, installed by 2012 at a tiny fraction of the cost of digging a new subway tunnel.

The Pedestrian Is King

(Paul Steely White is the executive director of Transportation Alternatives.)

Walkers and bus riders along 34th street outnumber drivers 9 to 1, yet cars hog most of the space. Even if it means inconveniencing motorists, there are many reasons that we, the citizens of the most pedestrian-rich city in the country, should applaud Mayor Michael Bloomberg's decision to correct this imbalance.

For starters, this plan will prevent deaths and injuries. On average, 59 walkers are struck by motor vehicles on 34th Street every year. The recent pro-pedestrian makeover of Broadway has already reduced traffic injuries and fatalities by 50 percent. The same rate of reduction for 34th Street would yield 30 fewer casualties per year.

Second, commuter times will be reduced. As the Straphangers campaign found in 2009, the M34 is one of the city's slowest bus routes, crawling along at an average speed of 4.7 miles per hour, which is barely faster than walking. The plan will speed the commutes of the street's 33,000 daily bus riders by a projected 35 percent. Though the plan does not include a new bike lane, its channeling of bus, car and foot traffic will make the intersections -- where 89 percent of bike crashes occur -- much safer.

Third, we'll have a more livable city. Because it is such a world-famous thoroughfare, 34th Street's transformation will accelerate the urban greening of our nation and our world. Cities like San Francisco and Chicago are already copying New York City's innovative bike lanes and tree-lined public plazas, and this new project will only make it easier for visionary mayors in other cities to strike a greener balance on their own streets.

As similar projects have shown, drivers will adjust their travel patterns, and some will even switch to mass transit. The project's payoff in terms of a safer street, quicker buses and a greener future is well worth any inconvenience to a minority of motorists.

Rethinking the 21st Century City

(Tom Vanderbilt is the author of "Traffic: Why We Drive the Way We Do (and What It Says About Us)." He writes the "Transport" column for Slate and blogs at How We Drive.)

The key word here is "mobility."

We tend to get hung up on discussions of "traffic," as in: How can we make the city's traffic flow faster? This goal has eluded city officials in the past and will only become more elusive in the future, for a simple reason: New York City will never be able to accommodate more than a small fraction of the total demand of people who might theoretically like to drive within it.

To build New York City to a scale that everyone who rides the morning subway into Manhattan's central business district could now travel (alone, as most do) by car, for example, would require, as was found by one back-of-the-envelope estimation, an additional 76 Brooklyn Bridges.

The sooner we begin to accept this reality -- and that "fixing" congestion without addressing (through pricing or other incentives) the demand-side is a chimerical pursuit -- the sooner we can start thinking about what a well-functioning 21st century city is actually going to look like.

Mobility, as opposed to traffic, addresses the question of moving the most people, most efficiently. One in 10 people who travel along 34th Street go by car. And yet the majority of the space is devoted to the individual automobile driver, even as pedestrians jostle on New York City's swollen sidewalks (they used to be wider) and packed buses creep along in a traffic stream created by the spatially wasteful line of individual cars. (You can't lure people onto buses without giving them a good reason -- like the possibility of actually getting somewhere at faster than a walking clip.)

The city is tackling these spatial imbalances elsewhere: Along Brooklyn's Prospect Park West, for example, it is proposing, not without controversy, removing one active travel lane for cars in lieu of a two-way bike lane. Underutilized most of the time, the excessively wide street serves as a drag strip of sorts for outbound traffic and a hazard to the many people going to and from Prospect Park.

We've spent decades in an earnest quest to accommodate the city to the demands of the car, to turn the city into some modernist "Motopia." But with the world's urban population projected to grow some 50 percent by 2050, that equation is going to have be reversed: The car must accommodate to the demands of the city. This does not mean turning entire swaths into pedestrian plazas or banning cars, but strengthening the city's transport network connectivity and reengineering the city's streets as multiuse spaces that will move people quickly, safely, sustainably.

In 1912, Lord Montagu of Beaulieu, the vice president of the Automobile Club of Great Britain and an authority on traffic problems, addressed an influential audience in New York. One of the greatest problems of cities, he said, was insuring that the "traffic of the city shall be dealt with in such a way as to make transportation cheap, easy and convenient." It's time we got serious about making this happen.

The Long Run

(Julia Vitullo-Martin is director of the Regional Plan Association's Center for Urban Innovation.)

What gives this plan a competitive advantage is that New Yorkers are so exuberantly greedy for street space -- especially in good weather -- that just putting down a few rickety chairs and ugly tables in the short run will lure them outdoors. This plan will look like it's working as soon as it is activated.

But in the long run, the same high design standards that have been crucial to successful street closings elsewhere will govern here. The city has to make sure that 34th Street -- both the roadway itself and the street furniture -- looks good and offers plenty of retail and entertainment attractions to keep pedestrians happy.

If it doesn't it will find, as Chicago did on State Street, that in the name of injecting life into a street you can in fact pull it out -- especially if you're asking people and buses to share space. So, yes, give this a try, but let's monitor it daily and not declare it a success until we know it's really working.