Human Transit

walkscore.com and the lure of the single "score"

The Conservative Planner has a thoughtful attack on WalkScore.com's methodology for calculating a simple "walkability score" for any neighborhood in America.  He's found several examples where WalkScore has given a high score to a place that's clearly hostile to pedestrians when viewed on the ground. 

One only had to take a stroll around the Hilton in downtown Atlanta to see the inherent flaws in this online tool. Type the Hilton’s address in Walk Score (255 Courtland Street NE, Atlanta, GA) and it will tell you that it is a “86 – Walker’s Paradise”.  [JW:  Actually, it now says "86 - Very Walkable']

The Conservative Planner continues:

Nevermind the fact there are 4- and 5-lane one-way streets with high speed traffic surrounding the hotel. Interstates 85/75 runs to the north and east of the hotel and is a major pedestrian barrier. The restaurants that are deemed by Walk Score to be nearby and within walking distance are buried within the Marriott and Hilton hotels, which are 1960s/1970s behemoths. It is hardly a walking paradise; it may be in a downtown area but the street system is strikingly suburban.

Fair enough.  But here's the Conservative Planner's suggested remedy:

Walk Score should not be used to analyze how walkable an area is as it does not consider the three most critical factors of walkability:

1. Connections: Walk Score can’t tell if sidewalks exist or not. It can’t even evaluate if there’s a street to connect to a destination that it tells you is within a walking distance of your address. You might need a machete and steel-toed books to walk to the doctor’s office.

2. Actual Route: Walk Score measures crowflight distance, not actual walking distance. I live in a neighborhood that has several destinations within a 1/2-mile radius. Too bad it takes me more than a mile to walk to them because of the lack of a pedestrian system along a 7-lane arterial highway with no crosswalks and poor connectivity despite its location within a streetcar suburb.

3. Land Use/Design: You could have the most “walkable” area according to Walk Score, but if you’re walking in front of a Walmart or other horribly designed commercial or residential strip, you won’t find the area to be very pedestrian-friendly.

These are all valid points, but if the Conservative Planner is really a planner, he/she would know how hard this bar is to meet.  Items 1 and 2 require that every local government in America provide a digitized map of its entire pedestrian network, showing not just which streets have sidewalks but where the usable off-road paths are, possibly including parking lots and vacant lots that you can safely cut across.  It should probably also show not just pedestrian signals but information on how they're timed.  Many local governments don't have this information.  Some have it only in the form of hand drawings on paper maps lovingly curated by the town's sole "pedestrian planner," who is allowed to play with these things in his broom-closet office so long as he stays out of the way of the road engineers. 

As for item 3, "design," well, sure, most of us would rather walk through a park rather than across a parking lot, but "design" by its nature refers to a subjective response, not a scorable metric.  (I'd make an exception for Robert Cervero's use of the word in The Transit Metropolis, which I suspect was selected more for alliteration in his phrase "density and design."  By "design" Cervero really means network connectivity -- the Conservative Planner's #2 -- measurable, say, by the percentage of a 1/4 mile air radius that's within a 1/4 mile walk on the pedestrian network; more on this here.)

What's more, even if we could agree on a scorable metric, you'd need a nationwide database of exactly how every lot has been developed, continuously updated of course.  The closest thing we have to that is Google Street View.  Is someone working on a computer algorithm that will study every Street View photo in the country and assign a universally-respected "design score"?  If so, perhaps we can look for improvement.

Bottom line:  What the Conservative Planner is really pointing out is that prevailing data structures are designed to the needs of the prevailing mode -- and right now, that's cars.  Yes, every local government should have a complete database of its pedestrian links, and yes, they should send it to Google so it can be added to Google Maps.  Only then will we have an automated measure of actual walking distance.

Meanwhile, the sensible response from WalkScore.com would be to move their "How WalkScore Doesn't Work" page to a more prominent place on the site.  A sensible response from the rest of us would be to remember that any methodology that reduces diverse inputs to a single score is not just an approximation, but an approximation shot through with value judgments that the score's consumer may not share.  WalkScore could help remind us of this by showing, on the front page where it displays the score, the separate "sub-scores" from which it's calculated, so that we can each decide if the factors are weighed just as we'd like.

UPDATE:  Matt Lerner of WalkScore tweets that they are working on these problems!

bus vs rail, an "oversimplified comparison"

Planetizen points out a new paper by Jeffrey R. Brown and Gregory R. Thompson of Florida State University, called "Bus vs. Rail: an Oversimplified Comparison."  From the abstract:

There is debate about the relative merits of investing in rail or express bus modes to improve regional transit performance. The debate largely assumes that both modes serve a single function of providing higher speed service to the central business district (CBD) over relatively long travel distances. The debate generally overlooks other functions that might be served by express bus and rail transit modes and thus ignores that the two modes may perform differently depending on the service mission they are assigned. Performance of the two modes is examined in four metropolitan areas with different strategies for providing high-quality, regional transit service: a CBD-focused strategy, a hybrid strategy that serves the CBD and a few other destinations, and a multidestination strategy that serves a widely dispersed set of destinations. ... It was found that the combination of a rail transit backbone and a multidestination service strategy leads to better performance than any other marriage of mode and mission.

In other words, (a) rail and bus technologies are tools, and no tool is right for every job, and (b) multi-destinational networks based on connections are more productive than radial systems that narrowly focus on a single downtown.  Regular readers of this blog will find these conclusions obvious, but it's interesting to see that this argument still needs to be made in the literature. 

UPDATE:  Let me tease this apart a little further.  I don't mean to imply that the work is redundant, but it does apply to a narrow range of cases, and it conflates "multi-destinational" with "rail" a little more than I'm comfortable with.

The authors' focus is on four cities which they locate on a spectrum from "CBD-oriented" to "multi-destinational."   

• Pittsburgh, which they identify as the most "CBD-oriented."
• Minneapolis, which they identify as transitional or hybrid.
• Atlanta and San Diego, which they identify as "multi-destinational."

These cities are all comparable in size, all have a mix of rail and bus, and all have some facilities for getting express buses out of traffic at least some of the time, ranging from the full busways of Pittsburgh to the freeway-shoulder operations of Minneapolis.

A CBD-oriented system (more commonly called a radial system) is one that views downtown as the sole destination of importance.  In such a system, people who aren't going downtown usually have to go via downtown, whether or not this is on the way.  A multi-destinational system is one that tries to serve trips to many destinations all over the city.  If you live in Los Angeles or Manhattan or Paris or Berlin, this distinction will seem silly to you, because your city has been multi-destinational for decades if not centuries and your transit system adapted to that reality long ago.  But most American (and Australasian) cities had a period, generally ending around 1945, when they had a single extremely concentrated downtown -- fueled, in many cases, by streetcar/tram networks that converged on it.  And at one time, it made perfect sense that this downtown would be the sole focal point of the transit network.

Since 1945, most cities have been becoming more multi-destinational, with more important destinations (employment, retail, leisure, etc) scattered all over the city.  Transit agencies were generally slow to adjust, especially since downtown tended to be where they were most appreciated and where the pre-car development pattern made it easy for pedestrians to get to them.  But over time, it's been necessary to adjust to a multi-destinational pattern in order to remain relevant to the life of the city as it is now.  The paper suggests that of the four cities studied, Atlanta and San Diego are relatively far along on that path, Pittsburgh least so.  (This seems to match Alan Hoffman's observation (here, page 67) that despite the introduction of busways, the Pittsburgh network has changed relatively little for a long time.) 

Note that the important distinction here is not that the network infrastructure is more or less CBD-oriented, but that the thinking of the transit agency is.  All four of the cities studied have CBD-oriented transit infrastructure that suits their CBD-oriented history, but they have thought about their networks in different ways. 

By comparing the experience of these four cities, the authors find that the most effective system is not the CBD-oriented but the multi-destinational.  Needless to say, your mileage may vary; it depends on how CBD-oriented your city still is, but even a city as CBD-oriented as Portland had great success with a multi-destinational network.  Most of the major network redesigns I've done have been about helping CBD-oriented systems still meet their CBD need while also being relevant to a wider range of destinations. 

My only quibble is that multi-destinational systems don't have to mean "rail and bus working together" because you can do the same thing in smaller or pre-rail cities by designing an all-bus system to work just the way a good bus+rail system would work.  I was the lead planner on a redesign for San Antonio around 2001-2, shortly after their voters had rejected light rail.  We did what we could to create a connective frequent network given that they only had buses to work with.  Following Portland's model, we did this with a mixture of high frequency grids in the denser inner city and trunk-and-feeder systems in the outer suburbs.  As a side effect, that project helped to intensify and simplify services in a concentrated corridor (Fredericksburg Road) where they're now planning Bus Rapid Transit, and light rail is being talked about again. 

Portland, too, did it with buses first.  Their multi-destinational route network (including the frequent grid covering the inner city and the trunk-and feeder structures for major outer suburbs) all were put in place by 1982, four years before the first light rail line opened.  Rail sometimes leads, but sometimes the result of good multi-destinational network planning, not its cause or starting point.

it's not a race, but if it were ...

This video, from The Overhead Wire via Great City, is making the rounds. It shows the side-by-side growth of six US rail transit systems, with the apparent goal of humiliating both late-starter Seattle and early-starter-slow-finisher Atlanta.

Note that the grey lines here represent commuter rail, which represents a very small level of investment (and frequency) compared to the colored lines, which are all rail rapid transit.

rail rapid transit maps, to scale

Neil Freeman recently posted a great collection of rail rapid transit maps, all drawn to scale, and all at the same scale.  The image at right, of course, is New York City,

He calls them subway maps, but of course that term suggests that the service is all underground, which few "subway" systems are.  What matters is that they're rapid transit.  In this case, they're specifically rail rapid transit, which is why Staten Island's rail line in the lower left appears disconnected from the rest.  In reality, it's just connected by rapid transit of a different mode: the Staten Island Ferry. 

(By "rapid transit" this blog always means transit services that run frequently all day in an exclusive right of way with widely spaced stations -- linking centers to each other, for example, rather than providing coverage to every point on the line as local-stop services do.)