The Convention Center is generally acknowledged as a boon to Philadelphia, generating hundreds of new jobs and supporting dozens of new hotels and restaurants since it opened in 1993. What the center has not been a boon to, however, is the stretch of Arch Street right at its front door.

After all these years, the block remains a dreary place with many empty shop fronts. Not a single restaurant has located there, despite the hordes that pour forth from the center's events. While the recent opening of the Fabric Workshop and the AIA Bookstore have infused the block's historic buildings with a whiff of life, the persistent ground-floor vacancies belong to the category I've come to call "The Mysteries of Philadelphia," for those things that just can't be explained.

But with the Convention Center in the final months of an expansion that will extend its reach for another block along Arch, and give it a presence on Broad Street, developers have begun circling overhead.

Unfortunately, the first project to land is exactly what Arch Street doesn't need: a parking garage.

The proposal comes from Realen Properties' Dennis Maloomian, the developer who gave us the "interceptor" garage, a massive concrete erector set at 16th and Vine Streets that was built in the mid-'90s to solve Center City's parking needs. Back then, Maloomian promised that it was only a matter of time before he snagged a hotel deal that would enable him to wrap the garage's unsightly decks behind a building. Philadelphia is still waiting.

Now, Maloomian wants to build another garage with another vague connection to a hotel. He told the city's Planning Commission last month that his five-level, 530-car garage would be located on a surface parking lot between Juniper Street and the historic Arch Street United Methodist Church, Addison Hutton's delicate Gothic Revival sanctuary at the corner of Broad Street. Maloomian is hoping to develop a hotel across the street in an early 20th-century skyscraper designed by Dennison and Hirons.

Even if Maloomian installs a hotel in the slender tower - most likely a boutique operation, with perhaps 200 rooms - a 530-car garage seems way out of proportion to the project's needs. Based on the bulky massing shown to the Planning Commission, the $27 million project would overwhelm the little church, which first held services while the Civil War was still raging.

The garage's utilitarian presence could also lead to Arch Street's being downgraded to a service street, much like Race Street on the other side of the Convention Center. To counter concerns, the developer has agreed to present more detailed plans at a public meeting Monday, at 6:30 p.m. at the church.

But it's already clear that the garage wouldn't just serve as an appendage to the future hotel. Maloomian's attorney, Peter Kelsen, acknowledges that the developer hopes to cash in on increased attendance at the expanded Convention Center, especially from gate attractions such as the Flower and Auto Shows.

It may be human nature to seek a garage close to your destination, but it's sure not good planning. With a major venue such as the Convention Center, the last thing cities want to do is encourage visitors to drive up to the front door en masse.

The desire to avoid such a traffic nightmare is one reason the exhibit hall houses almost no parking.

When the city made the bold decision to locate its Convention Center downtown, the expectation was that visitors would walk from nearby hotels or take public transit. After all, the hub of the regional transit system is a block away. Those who insist on driving are forced to park elsewhere, dispersing the traffic throughout Center City and reducing the likelihood of jams like those we see at the sports complex in South Philadelphia.

Building a garage-less Convention Center was a calculated risk. But guess what? Philadelphia's planners have been proved right. Conventioneers do walk to their meetings. Even suburbanites accustomed to driving into Center City will take the train to the Flower Show.

The Convention Center was a product of the same discussions that led to the 1991 Center City plan, a road map for downtown development that has yet to be surpassed, despite its now yellowing pages. City planners had real muscle in those days, so the 1991 plan was able to outlaw stand-alone garages in Center City and push them instead to the periphery.

That plan, in fact, paved the way for Maloomian to construct the interceptor garage. Its tough guidelines are also the reason he now needs a zoning variance to erect a garage on Arch Street.

Interestingly, such a garage would still be banned under the modern zoning code that the city is preparing to adopt. Approving the project now would mock the two-year-long effort to write a new code.

It was clear at last month's commission meeting that members are torn over Maloomian's proposal. Chairman Alan Greenberger wondered aloud whether any other profitable project might be built on the site, which has been vacant almost 30 years. No one really knows. But shouldn't the city wait for the $800 million investment next door to come on line before precluding the options?

It's also worth noting that, despite the cautions voiced in the 1991 plan, new parking facilities have continued to encroach on Arch Street. The Reading Market garage added 850 spaces at 12th Street, while the public garage under the new Family Court at 15th Street will add 265 - across from a garage under LOVE Park. What kind of place will Arch Street be when there is parking on every block?

Which leads us back to the question of why the Convention Center didn't do more to revive the street nearest its front door.

A recent study by the AIA's Community Design Collaborative offered some insight: Despite more than $1 billion of public investment in the Convention Center in the last two decades, not one penny was spent to improve the conditions on the building's perimeter, Arch Street in particular. The same crumbling sidewalks remain. The group produced a low-cost design that would dramatically improve Arch Street's appearance.

Maybe the street's failure to thrive isn't such a mystery, after all.

Contact architecture critic Inga Saffron at 215-854-2213 or