Wednesday, May 31, 2017

Transportation Should Not Trump Destination

New city to the left, old city to the right.
Of the original five squares in Philadelphia, only one of them is not a square today. Instead, Centre Square (also known as Penn Square) is occupied by City Hall. There are a bunch of smaller open spaces to the west of City Hall, including Dilworth Park and two plazas on the far side of 15th Street, one of which houses Claes Oldenburg's Clothespin (1976).

I think we should unite these shards of land to the west of City Hall to create a true square in Centre Square. St. Peter's in Rome has its square. City Hall should have a square.

We do this by closing 15th Street from JFK Boulevard to South Penn Square. To do this we will need to rework traffic patterns across a fairly large area, but before I get into the traffic weeds, let's have a look at how we got to where we are.

A Rare Opportunity
The area west of City Hall didn't always look the way it does now. Until the early 1950s there was an elevated train viaduct called the Chinese Wall, which ran from the Schuylkill River to a terminal facing City Hall (see map below). The terminal (designed by Frank Furness) and the Chinese Wall came down in 1953, and the City had a rare opportunity to redesign a large vacant space in the heart of a city that was already 250 years old.

The Chinese Wall, 1913.
I think it's fair to say that things didn't go as well as many people had hoped. There are a number of issues, but I'd like to focus on two things that I think underlie the traffic problems in the area - the street grid and the demands of the automobile.

The Street Grid
William Penn's 1682 plan for Philadelphia, with its rectangular street grid, recalls the layout of Roman military camps. The grid is a durable concept because it's useful, but we should remember that it was invented primarily with pedestrians in mind. Most Roman soldiers got around by walking. A few had horses; it helped to have a good seat, because stirrups hadn't been invented yet.

We should remember how good the Romans were at squeezing remarkable achievements out of very limited technical resources. For instance, how would you, as a Roman engineer, go about building a military camp, or castrum, on a rectangular grid? You used the Roman version of a surveyor's transit, which was called a groma.

The groma was a pair of straight sticks joined at right angles and mounted on a staff. Looking down one stick allowed you to shoot a straight line. Then, if you walked around and looked down the other stick, you could shoot a right angle. You could only shoot 90 degree angles with a groma. If I were an engineer, I would find that a pretty good argument for laying out an army camp in a rectangular grid.

The Roman castrum always came with two large streets that divided the camp into quarters. Where these big streets met, in the middle of the camp, there was a large open area. This was the parade ground, and the unit commander's headquarters was located on this square.

In Philadelphia we call these big streets Broad and Market; the central square is the home of City Hall.

I suspect that the grid worked pretty well for the Romans. At each end of the big streets, there were gates. A commander could readily mass troops along those streets and in the central square and then sally forth through any of the gates.

The main shortcoming of the grid plan is the lack of diagonal movement. In early modern times this issue was addressed by adding diagonal boulevards to the grid. Major L'Enfant did this in his plan for Washington, D.C., and Baron Haussmann employed them extensively in his reconstruction of Paris in the mid-nineteenth century.

Haussmann did not build the most famous Parisian boulevard, the Champs Elysees, which has roots extending back to the late seventeenth century. And it is the Champs Elysees which provides the inspiration for the Benjamin Franklin Parkway in Philadelphia.

It's important to remember that the boulevard concept, like the grid concept, was born in a world without cars. These streets were for pedestrians and also people who liked to ride around in horse-drawn carriages.

Cars Change Everything
And then came the cars. It's tempting to blame the beginning of our traffic woes around City Hall on the Benjamin Franklin Parkway (built between 1917 and 1926). Or you can blame City Hall (built between 1871 and 1901). Or I suppose you could go back to the original William Penn plan and say that the two big streets meeting in the middle was a good idea for a Roman military camp, but that the intersection in the central square would clearly become a choke point when the concept was applied to a larger settlement.

Here's a map showing the central part of Philadelphia in 1859. Notice that the central square is already unlike the other four squares. In the outlying squares, the streets skirt the perimeter. In the central square they plow right through the middle, dividing the square into four pieces. A little over a decade later, City Hall started to arrive in the central square, at which point traffic was pushed to the periphery.

Market and Broad intersecting in Centre Square, 1859.
What would have happened to the central square if City Hall had not arrived? I suspect that it would have become a very large traffic circle, similar to Logan Square. We can only hope that the middle of the square would have an equally attractive water feature.

The street system is not the source of our problems. The problems came with the cars, and the problems came from the cars. After the introduction of the Model T Ford in 1908, cars hit cities like a tidal wave.  Cars are big and heavy and fast. They needed more space to move than the streets had, and they needed places to park. Starting in the 1920's, cities began to rebuild themselves to accommodate cars.

Peter D. Norton, in his Fighting Traffic (2011), goes through what happened in magisterial fashion. (I have reprised some of his arguments in Cars and Bikes - The Back Story.)

The reconstruction was managed by members of the new profession of traffic engineering, many of whom had gotten their start in municipal water departments. They effectively reported to the American car manufacturers and their allies. There were two key goals - a bigger pipe, and faster throughput.  The engineers knew how to move water, and they knew they needed a big pipe and high speeds to satisfy a demand that skyrocketed every year.

From this basic situation you get the Interstate Highway System, based on limited access, many lanes, and high speeds. This system actually works well out in the cornfields of Iowa. Drop it into a city that was designed in the seventeenth century, and there are problems.

It's not that you can't do interstates in the big city. Look at the Vine Street Expressway. I wish it were covered, and I wish the traffic volumes and number of crashes were lower, but you can do this. We could actually live with automobiles, if the car lobby were reasonable.

But what doesn't work is trying to turn local Philadelphia streets into fake interstates. And that's what's happening on 15th Street by City Hall.

The Nitty Gritty
Okay. I told you I would get to this, and here we are. Let's have a look at 15th Street by City Hall. The traffic engineers took one look at 15th Street, and they said "big pipe." I won't go through the history, but here's what's going on today.

Here are the feeders for the big pipe on 15th Street, which for out-of-town readers runs south past the west front of City Hall.

Let's start at the north, with the Vine Street Expressway. Both the eastbound and the westbound exits land you on 15th.

The Ben Franklin Parkway comes in by way of a little two-way section of Arch between 16th and 15th, just north of Love Park.

Arch Street between Broad and 15th, by the Municipal Services Building, is one-way westbound (we'll come back to that) and it also feeds 15th Street.

Just south of Arch, the 810-car garage under Love Park has an exit onto 15th.

At John F. Kennedy Boulevard, just south of the Municipal Services Building, Broad Street feeds into 15th by running around the northwest shoulder of City Hall.

And then Market Street butts into 15th on the west side of City Hall.

All this takes place in the space of five blocks.

I've written a bit about 15th Street by Love Park (for instance, Crossing 15th Street), so I'm going to limit myself to a comment on the intersection of 15th and Market.

Who thought it would be a good idea to have five lanes of traffic merge at a T intersection with another four lanes of traffic and then immediately split into three separate streams, flowing to 15th Street (south), Broad Street (south), and Market Street (east)?

The Furness Plan
This was a conscious decision. Previously there were two separate streets here - the street by the west side of City Hall, and then 15th Street. When Frank Furness designed the Broad Street Station, he preserved 15th Street by having it flow through the building. Here's his plan.

From James F. O'Gorman, The Architecture of Frank Furness (1973) p. 183.
The later arrival of the Benjamin Franklin Parkway created further issues, which I think have never been satisfactorily resolved. However, traffic on the Parkway has decreased since the construction of the Vine Street Expressway, and I think it should be possible to make things better in this area, provided people are open to new thinking.

A Different Approach
What happens if, instead of concentration and high speeds, we ask our street designers to look at diffusion and low speeds? In other words, let the grid do something it's good at.

Let's start with two easy ones.

Make the 1400 block of Arch two-way. The Benjamin Franklin Parkway ends at 16th and Arch. You can continue on to the 1500 block of Arch, north of Love Park, but then you are required to turn south on to 15th. Why can't you keep going east on Arch? Because it's one-way westbound from 15th east.

I think we should make Arch two-way down to Independence Mall at least. Then it could effectively serve as a distributor for the Ben Franklin Parkway east of Broad. But for now I'm happy to concentrate on the 1400 block, where we have some work to do.

I'm actually a fan of Vincent Kling's Municipal Services Building, but it does have some problems, not least of which is the remarkably self-indulgent porte-cochere on Arch Street, which takes up two traffic lanes and spawns a wide sidewalk that almost nobody uses.

Sidewalk and porte-cochere at Municipal Services Building.
I'd demolish this porte-cochere - it's actually a free-standing structure - and narrow the sidewalk and let motorists go both east and west on this block.

Close the Love Park garage exit on 15th. These exiting vehicles cause a lot of craziness as they try to move left - the lane they exit onto is a right-turn only lane. This block is currently hell on wheels for pedestrians and motorists alike. I'm amazed that people actually ride bicycles on this block, but they do. There's another perfectly adequate garage exit on Cherry Street.

Okay. Now for the heavy lifting.

Close 15th Street from JFK Boulevard to South Penn Square. In Vietnam there was a road that French soldiers called la rue sans joie, or the street without joy. Greta Garbo starred in a film of the same name in 1925.

Fifteenth Street west of City Hall is a street without joy. There's no fixing it, in my opinion. So we should close it and allow Dilworth Park to expand and occupy the whole space from City Hall to the Clothespin.

How you do this is a little complicated, so please bear with me.

Make Market Street two-way from 20th to 15th. It's already two-way west of 20th and east of City Hall. I don't know why it's one-way on this stretch. Make a nice turnaround circle at 15th Street.

Provide similar treatments for the stubs of 15th Street and South Penn Square that would provide access to the buildings on the southwest corner of this new plaza.

My brother points out that you could marry up South Penn Square, 15th Street, and Ranstead, which extends from 15th to 16th. I think this is a nice solution, although I prefer mine.

Market Street will no longer be a through street in Center City. However, if you think about it, neither Market nor Broad have really been through streets in Center City since at least 1871. We've just been pretending.

Make JFK Boulevard two-way for its full length. Currently it is two-way from 30th Street Station across the bridge to 20th Street, and then one-way westbound between 20th and City Hall. We need to reroute Market Street's eastbound through traffic to JFK Boulevard. Motorists could make this move out by 30th Street Station, or on the east side of the Schuylkill at 20th, 18th, or 16th.

With no traffic on the west side of City Hall, the streets on the north, east, and south sides of City Hall all need to become two-way.

Here's some of the upside. A motorist coming from 30th Street Station can run straight down JFK to the east side of City Hall, make a quick right and a quick left, and then continue on Market Street to the Arden Theater for a reprise of Sweeney Todd.

Similarly, a motorist coming down Broad Street to City Hall can make a few quick turns and again be on east Market headed to Christ Church, one of George Washington's hangouts in Old City.

Currently, a motorist coming down Broad who wants to go east on Market has to go around three-quarters of City Hall and brave some of the nastiest traffic in the city.

Use Roundabouts. I think a number of the intersections under discussion - for instance, the intersection of Broad with JFK on the north side of City Hall - would benefit from the addition of roundabouts. These are basically very small traffic circles. I've seen them in action. In my experience they slow traffic, encourage polite driving, and in general work very well.

It's a Lot of Work. What's the Payoff?
A walkable city. As the headline of this story says, transportation should not trump destination. We need to have a there there, when people get out of their cars or off the train or bus, or when they dismount from their bikes or just show up by walking, which is what I usually do. And the there should not just be inside. We need outdoor public spaces, and frankly Philadelphia does them very well. It just needs to do more.

Things seem to be headed in this direction. Recently there have been suggestions in New York City that it is finally time to close Times Square to cars. We'll see how that goes. So much depends on elections.

But I think the Schuylkill Banks in Philly show that it is possible to blend hard-core transportation with bucolic recreation in a way that is highly successful for both. The early plans for the Schuylkill Banks called for the rail lines by the river to go away, but they didn't. And so we have a riverbank park that is easily accessible across rail lines that carry volatile petroleum and smelly garbage, and after years of settling in, and many, many snarky conversations, and the construction of some pretty amazing blast walls, things seem to be going reasonably well.

I'm not saying it's nirvana, but I am saying this is the way of the future.

The two most successful Center City parks, aside from the Schuylkill Banks, are probably Rittenhouse Square and Fitler Square. Although they don't have the industrial challenges of the Banks, they do have to deal with cars, which is the issue up by City Hall. And the answer is, if you have a nice park with greenery and a water feature and benches and maybe a few statues that kids can climb on, and the park is accessible across streets that are not terrifying, and if the din of the car traffic is low enough to meld with other background noises, and if maybe you have a certain amount of programming, then you've probably got yourself a successful park.

I think we could have a very successful park filling the open space on the west side of City Hall. People will say, if you build it they won't come. This is Philadelphia, and of course people are going to say that. But I don't believe them.

Plaque located in the northern arcade of the Municipal Services Building. It commemorates the Reyburn Plaza Bandstand, which was demolished in 1962.

The maps reproduced in this story are from the Greater Philadelphia GeoHistory Network.

See also Fixing Arch Street at Love ParkGordon Cullen and the Outdoor FloorLove Park Redesign: Why Are There Still Five Traffic Lanes on 16th StreetRichardson Dilworth, an Urbanist for the AgesRoad Diet by Love Park - a Natural Experiment.


  1. Some diagrams and sketches of your plan would go a long way. Many interesting ideas. Making 1400 Arch St. two-way is particularly intriguing. Not sure about two-way traffic on the north, east and south sides of City Hall. Traffic at Logan and Rittenhouse Squares work well because they are basically roundabouts. The surrounding streets all flow the same direction around the square.

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