Tuesday, July 28, 2015

On Central Bus Terminals

City Lab says

I say:

Bus terminals are fine. Central bus terminals are problematic. Using a central location for for end-of-line 'terminal' functions means you need space to store a lot of buses, which means you need a lot of real estate, which means 'central' bus terminals are never central. More successful are transit malls, where many buses load and unload, but without having a huge array of idling buses, noises and belching exhaust. One of the things that made Fung Wa so so successful was that their use of curb-space was illegal, so they had to be FAST in loading and unloading, so they couldn't afford to 'store' buses.

Monday, July 20, 2015

A Concise History of Rail Transit in America

Modern transit comes from two historic lineages: Steam railroads, and horse-cart street railways. To operate in an urban environment, steam railroads underwent a number of modifications. To reduce conflicts with street level traffic, were either elevated or under-grounded. At some point, they were also electrified, typically use a third-rail system. Once that occurred, expansion required the continued use of grade separated, exclusive guideway, so no one touched the third rail and died. In contrast, street railways were electrified as trolleys, using a pantograph. (Cable-cars can be thought of as a 'dead branch' alternative to electrification). The converging modes of electrified heavy rail and street railways were hybridized as the "Inter-urban". Electrified the whole-way, using a pantograph, and running in a mix of at-grade and tunnels. After the second World War, almost all pure street running 'trolley' systems were 'bus-tituted' out of existence, while some inter-urban systems survived. The survivors all had some off-street running-way, viz: RTA Streetcars, San Francisco cable car, MBTA Green Line & Ashmont–Mattapan High Speed Line, SEPTA Subway–Surface Lines: Suburban Trolley Lines & Girard Ave Trolley, RTA Rapid Transit: Blue and Green Lines, Newark Light Rail, Muni Metro. Between ~1930-1972 is sort of a 'Dark Age' for urban rail--almost nothing new is built. Then there is a resurgence of heavy-rail systems to deal with traffic congestion: BART (1972), Washington Metro (1976), MARTA (1979), Baltimore Subway (1983), and Miami-Dade (1984). All run at-grade in the suburbs, and in tunnels in the city center. About 1980, America adopts the Stadtbahn/'City Rail' concept from Germany, and APTA coins it 'Light Rail'. It runs at-grade in the suburbs, and at-grade in the city-center, like the inter-urbans. Being regulated as 'light' rail, it is allowed to operate in mixed-traffic with cars, making it easier/cheaper to build. Over time, the surviving inter-urbans are rebuilt/revitalized, making use of the same vehicles as the new 'Light Rail' systems. Circa 2001, Portland reinvents the 'streetcar', which runs at-grade, in mixed traffic, with smaller vehicles, and making extensive use of single-track.

Now, to get back to what is 'Rapid' transit: Rapid transit is something that has it's own (unshared) guideway. Subways, elevated rail, commuter rail all clearly meet this standard, as do most of the 'Metro' systems of the 1970's heavy-rail revival. But the surviving inter-urbans and new light rail systems are a confusing mix: They have portions of exclusive guideway, so they have rapid transit portions. But LRT means 'Light Rail Transit' rather than 'Light RAPID Transit'. This gets confusion in the context of BRT, which actually means 'Bus RAPID Transit'. BRT gets developed in Latin America as a sort of bus version of a heavy rail system--buses with unshared guideway. But that's another topic. In summary: HeavyRail = Rapid, Streetcar !=Rapid, LRT !=Rapid...but does have sections that could be. (Cable-cars get lumped in with LRT largely on the basis of Cable-car != heavy-rail.)

And finally: Metro!=Heavy-rail, but Metro ⊂ Heavy-rail. Freight, Metro, Subway, Elevated, Commuter Rail ⊂ Heavy-rail.

=     Equal to
!=    Not equal to
⊂    Is a subset of.

Friday, July 17, 2015

Reflecting on this article, I wrote:

Much planning is done by architects, who are totalitarian visionaries. This is fine, when they are limited to perhaps a dozen acres, but a disaster when combined with city-wide 'comprehensive planning'. 'New' planned cities uniformly fail (or mutate from their original plan); this failure can be attributed to a lack of understanding of how cities actually function. Our efforts to address congestion through construction is a manifest example of this--we are trying to manage a system of interactions, but our conceptual framing of the system does not match the bounds of the system. Hence the need for the 'fuzzy' bounds discussed.

Density is an areal measure; Intensity is the point measure.

 Essentially, Any county-level estimate of population density is trash. What is needed is a continuous measure of density, rather than an areal unit of density. The pixel maps of employment density generated at <http://onthemap.ces.census.gov/> represent such a method. It would be difficult but feasible to generalize such a method to GIS. It would require assuming population uniformity at the block level, but doing so would certainly be better than doing so at the County level.

If you aren't familiar with them, I recommend Jarrett Walker's (Human Transit) blog; specifically, the blog posts on 'The Perils of Average Density' and 'Portrait of a City as a Squiggly Line'.

Monday, July 13, 2015

On Garden Cities

Not a fan. Like TOD, Garden cities are intended to be independent cities, but most wind up as suburbs or larger metropoli. In locations too distant from central metropoli, they tend to suffer the fate as most 'New' cities--eventual or immediate failure. Our understanding of how cities work is still too poor to bring cities into existence without passing through some sort of embryonic form.

Thursday, July 9, 2015

"All those Empty Buses"

Most Buses are Empty
Cars are empty most of the time.
So are roads. 

But Why Run Empty Buses?
If something is going to be used part of the time, it has to be available all the time. 

But It Costs to Run Buses!
It costs to run cars ($0.57/mile).
It costs to maintain roads ($250,000/mile/15 years).

Nobody Wants to Ride Transit!
Nobody likes paying 1/4 of their paycheck for gas, either. 
But people should get to choose which they prefer to do.

Buses Are Subsidized!
So are cars. Roads are provided free, and they aren't cheap.

The Gas Tax Pays for Roads!
The Federal gas tax pays for highways..
...except when it doesn't (Highway Trust Fund is broke)
...except when it doesn't (deferred maintenance)

You Want Everyone to Take Transit!
I want everyone to have the option to take transit.
YOU want everyone to drive.
YOU want everyone to have to own a car.
And YOU want to strand everyone else (old, young, poor, disabled) without a car,
or leave them dependent on someone who does have a car. 

The untruths, half-truths, misconceptions and bullshit that characterize conversations about transit. 

Gets My Goat

Articles like this never fail to get my goat:
"Your city bus costs more per mile than a first class overseas flight"

...it claims.

But the devil is in the details:

These public transit systems charge a flat cash fare to go one mile within the center of their cities. So if you're using one for a quick trip, you'll pay the following:
New York Subway, Boston T: $2 per mile
Chicago El: $2.25 per mile
Atlanta MARTA: $1.75 per mile
Los Angeles subway: $1.25 per mile
San Francisco MUNI: $1.50 per mile
London Tube: £4, or $5.63 per mile (plus more if you travel beyond the central city)
Paris M├ętro: €1.60, or $2.01 per mile
Cairo metro: 1 Egyptian pound, or 18¢ per mile
Hong Kong MTR: HKD$7.7 or 99¢ per mile

The author assumes that the default fair is for ONE mile of travel. Nevermind who uses that same transit fare to travel much further. UTA's default fare was $2.50 for a bit...but that provided 2.5 hours of travel time, enough to get from one end of the system to the other. Which takes 2.5 hours, and covers (fully) 83.1 miles of distance, or 0.03008423586 cents per mile. Given that the IRS allows you to deduct 57.5 cents per mile for driving.

Long story short, this points out two things:

FIRST: Short trips are more expensive than long ones.
Airplanes are different than buses.  Air resistance increases with the square of velocity. The faster a vehicle travels, the more air resistance opposes it, and the more power is needed to overcome it. An airplane traveling at 640 mph generates 16 times as much air resistance as an airplane traveling at 160 mph, despite the fact that it's only going four times as fast. To minimize this effect, airliners fly very high (39,000 feet) where the air pressure is much lower. (For reference, Mt. Everest is 29,000 feet at the peak). For a flight, all the cost is in getting up in the air, to cruising altitude (after which, the plane largely just maintains a semi-ballistic glide through the thin air of the upper atmosphere, all the way down. Most of the flight is spent at 'cruising altitude'. The cruising altitude is selected on the basis of algebraic equation containing the costs per unit of vertical travel at a given height, and the cost of getting to that height. The way the math works out, its always cheaper to go to where the air is thin, so the cost of a flight is largely invariant to the distance traveled.

It's not how good something is, it's how good it is compared to its alternative. Every trip takes time, and costs money. The default alternative for short trips is walking, which can be very time consuming, but costs (effectively) nothing. Whether it's worth spending money for higher speed depends on your own personal cost of time. If your time is worth $10 an hour, saving 1/2 hour is the same as saving $5. So every 6 minutes of your time is worth a dollar. If the bus fare is $2, take the bus anytime doing so will save you 12 minutes, or anytime you have to walk over 6/10 of a mile.