Philadelphia's Streets Department announced last night that it finally has a South Street Bridge design it can live with. Given its insistence on architecture that is graffiti-proof, mugger-proof, homeless-proof, bird-proof and jump-proof - not to mention cheap and maintenance-free - the choice is about as good as anyone might expect at this point.

The design, which was presented at a public meeting, certainly beats the version the city was promoting back in May. That one involved leaving the architecture out of the $67.5 million bridge project altogether.

At the last minute - perhaps after registering the neighborhood's collective cry of despair - the Streets Department reversed course and allowed the architectural consultants, H2L2, an extra three months to finish their work. The designers were able to produce three variations, which were shown to the community in July for comment.

A group of city officials, including Mayor Nutter and Planning Director Alan Greenberger, made the final cut, choosing Option 3, a large, faceted light structure that resembles a Chinese lantern propped on four legs.

Calling the design that was unveiled last night "architecture" may be stretching things a bit. From the start of this hugely flawed process, which began more than a decade ago, Philadelphia-based H2L2's assignment has been to embellish a standard, highway-style bridge created by the engineers at Gannett Fleming of King of Prussia. Their design work serves as camouflage, like the pasties on a strip-club dancer.

Still, it's a much better outcome than the no-design alternative that was threatened in the spring.

In the end, the city appears to have favored Option 3 because it satisfies a long checklist of demands: It is light, inexpensive, and nearly indestructible. The 33-foot-high structure should be friendly to pedestrians and easy to see from afar.

For all those virtues, I don't believe that Option 3 was the best design H2L2 produced in this round. Option 2 is punchier architecture. Its pairs of thin, tapered candlestick towers, which grow from the water and flank the bridge's overlooks, have a sharper and more distinctive form than the lanterns. But apparently the city was concerned that the concrete towers could become targets for graffiti, and hiding places for muggers, so they were rejected in favor of Option 3.

The lanterns are certainly acceptable. They are big and simple enough to make their presence felt on the skyline. That's important because the South Street Bridge is a spectacular visual gateway to Center City's proud array of towers, especially for people driving into the city from the south.

For H2L2, the big problem all along has been to find a design that was easily readable at a distance, yet scaled for the pedestrians and bicyclists who use the South Street bridge as a neighborhood connector between Center City and the University of Pennsylvania.

So, it's good news that Option 3 is more delicately proportioned than some of H2L2's earlier attempts. The lantern shade, which is just eight feet across, should be light enough that people stopping at the bridge's four overlooks won't feel they are standing under the oppressive weight of a heavy tower. The same four-legged lantern design will hover over each of the overlooks, effectively acting as both a beacon and a canopy.

The plan now is to construct the upper part from panels of impact-resistent, milk-colored glass, framed in stainless steel. A screen on the underside will keep pedestrians from being blinded. Since the light will be generated by LEDs, heat or glare shouldn't be a problem.

The other strength of Option 3 is that it neatly matches the rest of the bridge's architectural language, especially since the new span is under construction and on schedule to be completed in November 2010. The segmented columns at the base of the overlooks have already been designed, so it does make some sense to have the glass canopies pick up the same rhythms and faceted shape. The base now includes a lighted glass panel across its surface to match the lantern.

The selection of the bridge's architectural decoration brings to a close one of the most chaotic civic design processes in recent memory. When the reconstruction project was started in the late 1990s, city officials promised that the South Street Bridge would be a corrective to the interstate-style Walnut Street Bridge. But the first design shown to the public in 2001 was anything but an improvement.

Even though this bridge is a Philadelphia landmark, it was left to community leaders to battle city officials over the design.

Ultimately they were able to persuade the engineers to stay true to their early promises, and create a bridge that does not privilege cars over pedestrians and bicyclists. Bike lanes and sidewalks were widened, crosswalks were improved, and the crash railing was made to look more urban.

While community leaders had to push hard for those changes, none of it would have happened if the Streets Department had not evolved in its thinking and come to recognize that the Schuylkill bridges are an extension of the city streets - rather than an extension of a highway access ramp.

"The Streets Department worked with us. H2L2 worked with us. Gannett Fleming got behind us in making real changes," said James Campbell, an architect who helped lobby for the design changes.

With those lessons learned, perhaps the next time the city undertakes such a high-profile infrastructure project it will start off right, by thinking of design as more than something that can be pasted on at the eleventh hour.

Contact architecture critic Inga Saffron at 215-854-2213 or isaffron@phillynews.com.