The Vitality of the Transit City is Dependent on Transit Expansion--Applying Metcalfe's Law

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Below is a reprint from March 2005. I was reminded of writing this in reading an entry on The Bellows, On Transit Networks*

Given the paper that I am (still) writing for class it's funny that my perspective has changed somewhat given the last two years. It's because the value of the network and the investments made aren't equally distributed. The WMATA system is polycentric, oriented to serving more and more distant suburbs.

Subway stations at the core of the city of Washington. At about 15 square miles, the core of the heavy rail service in DC has a subway station density of 2.0/sq. mile.

Normally that wouldn't be that helpful to the center city, but because there are 30 stations in the core of Washington, DC, that area is much more akin to a monocentric transit system, and the benefits are much greater. Is it a surprise that most of the DC neighborhoods served at the core of the WMATA heavy rail system are healthy or in the process of revitalizing?

Even so, since most of the system expansions are in the suburbs, that isn't very helpful to DC proper. And more of the expansions being proposed are farther and farther away from the center of the region--other than an infill station proposed for Potomac Yards in Alexandria as part of the Constrained Long Range Transportation Plan for the region.

The way the financial formula works for funding the WMATA system, a big portion of the fee is based on the number of subway stations in the jurisdiction. DC has almost half the stations (40 of 86) so we pay a lot. While expansion will add payments from other jurisdictions, the formula will still tag DC plenty. So DC needs to take care of itself, not expecting the ideologues in Virginia, and the sprawl-enablers in Maryland (see "Plan for Metro to BWI Gaining Momentum" and "Prince George's Sees Andrews As Hub of Development" both from the Post) to provide any help or direction to transit capacity issues within DC.

Note that the Transit Element of the Arlington Master Transportation Plan (Draft) does mention the blue line separation proposal for the WMATA system. To the best of my knowledge the DC 2030 Transportation Vision Plan does not.

Came across a critical document by Alexandria about its transportation planning. They have since changed a number of things including launching a webpage comparable to Arlington's. However, I called the office today and found the person I talked to not too helpful. (Even so, I can't imagine DC being as critical as Alexandria in terms of self-evaluation.)
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A lesson from the world of computing:

Robert (Bob) Metcalfe is the inventor of the Ethernet protocol, and I think one of the founders of 3Com. He's rich, nice, and a bright guy. (I met with him once when I worked on a business startup producing live satellite television broadcasts about enterprise computing. Unfortunately, we were a bit ahead of our time, and undercapitalized, so we didn't end up getting rich, even if we knew about the graphical Internet a year or two before everybody else.)

He has posited some thinking on the value of networks that is now referred to as Metcalfe's Law. Jakob Nielsen, in his great website about information architecture, posted this:

Note: Nielsen was writing about the attempt to create proprietary systems and sub-networks within the Internet/WorldWideWeb world, but Dr. Transit thinks we can use this train of thought to develop our thinking more broadly about the region's transit infrastructure.

"Metcalfe's Law states that the value of a network grows by the square of the size of the network. So a network that is twice as large will be four times as valuable because there are four times as many things that can be done due to the larger number of interconnections.

Because of Metcalfe's Law, the largest network always wins over smaller networks, even if the smaller network has some larger initial value due to some special-purpose feature or benefit. As the networks grow, the square factor ultimately tips the hand in favor of the large network..."

(Note from Dr. Transit: this by the way is an argument for strengthening Metrorail, and for not standing by when the State of Virginia contracts separately from Metrorail to build the Tysons-Dulles expansion. After all, why not capture the knowledge and learning that will occur as part of the planning and development and construction of the extension, and apply it to other projects within the Washington region, rather than let it dissipate in the knowledge bowels of various private contractors?)

"Metcalfe's Law provides much of the explanation of the success of the Web relative to earlier hypertext systems like HyperCard, Intermedia, and NoteCards. They were all much better than the Web and had features ten years ago that we are still sorely missing on the Web. But the Web was universal and the other systems were proprietary. You know who won.

The law is usually quoted in terms of growth of the network, but we can run Metcalfe's Law in Reverse and use it to characterize the effect of cutting a network into pieces:

The value of partitioning a network into N isolated components is 1/N'th the value of the original network.

This new law follows directly from the original Metcalfe's Law. Each of the new components has a size of 1/N'th the size of the original network. Thus, its value is 1/(N2) of the original value. At the same time, there are N of these new mini-networks, so the over-all value is N * 1/(N2) = 1/N

The value of the full Web is currently about $300 Billion according to an analysis published by Cisco. In three years, the value will likely be around $1 Trillion. Let's assume that the various attempts to split the Web succeed to the extent that it is split into 5 parts soon and 10 parts in three years. The current value of the Web would be reduced from $300 Billion to $60 Billion - for a loss to society of $240 Billion. Each of the current "mini-nets" would be worth $12 Billion
The future value of the Web would be reduced from $1 Trillion to $100 Billion - for a loss to society of $900 Billion."

See why pro-DC Dr. Transit believes in thinking regionally (at least for transit)?

More links, more connections, a wider ranging network, increases transit efficiency and access in a way that increases economic returns for more and more people in the region.

This is why Dr. Transit now believes that public investments in non-automobile-centric transportation (from pedestrian-oriented streetscape improvements to bike routes to pervasive bus systems linking to rail transit, to creating a higher-speed railroad connection from Washington to Richmond, to streetcar and Metrorail expansion, etc.) are the most important public investments that governments can make to promote economic development (other than on education, and public safety), provided that the planning is sound and the transit goes places that people need and want and have to go to (i.e., more like Metrorail and less like the subway in Baltimore).