Posts about Walk Score

Sandra Moscoso wrote yesterday about how Code for DC's School Decisions Project has been gathering coders who want to use open data to help parents, students, and policymakers. This is one of the graphs they created at the recent Open Data Day using data from the Office of State Superintendent of Eduaction (OSSE).

I've asked to get access to the raw spreadsheet for this graph so we can look at, for example, which schools each dot represents. Here are the accountability categories by school. I will add the spreadsheet with WalkScore matched up with category when it's available. Update: here's the data as a CSV file.

A few things immediately jump out. The most successful DCPS schools have high Walk Scores, while the least successful ones mostly (but not entirely) cluster in the lower range. This may reflect the fact that a public school's success has a lot to do with the socioeconomic status of the neighborhood, and the local retail that is a big part of Walk Score locates in areas with higher incomes.

That income effect is also very pronounced in the graph Sandra posted yesterday:

That's not the case with charter schools. 3 of the 5 "reward" charters are in low-Walk Score areas (which could mean something, or just be a consequence of little data), while the "Rising" charters are basically all over the place. This may have a lot to do with the simple fact that since charters have to find and pay for their own space, they're in all manner of locations.

An interesting future step might be to correlate the school tiers with some data set about land prices or rents, or resident incomes. That could help illuminate whether charters end up locating in less-expensive areas, because they want to serve poorer residents and/or because they need cheaper land.

What do you see from looking at this data?

The score combines 4 factors: Bike lanes, hills, the distance to various amenities, and the percentage of people who bike commute. In DC, that concentrates the score heavily in the center. Already there is more in the center, and it's a lot flatter, which is the reason the city centers where it does.

It's important to recognize that this is just descriptive, not proscriptive prescriptive. In other words, places where few people bike get demoted in the rankings, which helps people understand and visualize where people don't bike today. But that doesn't mean that the places shaded closer to red couldn't become great places to bike, though there's nothing to do about the hills.

DC comes in behind Minneapolis, Portland, San Francisco, Boston, and Madison, but ahead of Seattle, Tucson, New York and Chicago. Do you think this is accurate?

"With gas prices expected to hit new highs, more people are riding transit, walking and biking to save money. And being able to leave your car at home more often is great for your wallet, your waistline and the environment," he said.

The company generates Transit Scores using data provided by transit agencies, and takes into account the number of nearby transit routes (weighted differently by mode), how often those routes run, and how far away the stations are from any given point. A city's score is based on a population-weighted average of all individual point scores. For an excellent discussion of the Transit Score methodology, check out this exchange between transit expert Jarrett Walker and Walk Score's Matt Lerner from early 2011.

Overall, it's fair to say that few American cities score well on the system. Of the 25 largest cities that make their transit data available to the public, only ten topped a Transit Score of 50, which is the lowest score qualifying as "good transit," described as "many transit options nearby." Most (14) fall into the "some transit" bracket, and the 25th-highest Transit Score among the cities evaluated—Raleigh, NC—is a 23, the upper end of "minimal transit."

The scale is non-linear; that is, raising a city's Transit Score from 70 to 80 would take much more work than raising it from 60 to 70. Because of the population weighting, the more people who live in a city, the harder it is to raise the score: As the Walk Score website explains, one additional bus route means a lot more for a small town than it would for a big city.

Furthermore, rail transit (including subways and light rail) is weighted at twice the value of a bus route, with ferries, cable cars, and other modes splitting the difference between the two. These numbers weren't pulled out of thin air—they reflect research that shows a range of effects of different transit modes on the value of surrounding land.

Because of this, Transit Scores will tend to be higher in the center of cities where multiple rail lines converge, but where residential population may not be at its densest. It's not hard to see how development near rail stations could make or break a city's Transit Score.

No doubt, Transit Score is a useful way to compare different neighborhoods within a city, and now entire cities as a whole. But it primarily reflects how easy it is to get to transit, rather than where you can go and what you can do with transit once you're on it.

Cross-posted at Streetsblog Capitol Hill.

The regional average of Metro's 86 stations is 72.1. As one would expect, the District of Columbia is the top-scoring jurisdiction, with an average of 81.6. The remainder of the "diamond," Arlington and Alexandria, is a clear second place. Montgomery is in the middle, with Fairfax and Prince George's trailing well behind.

A few Metro stations are right on the borders of jurisdictions: Friendship Heights between DC and Montgomery, and Capitol Heights and Southern Avenue between DC and Prince George's. This analysis counts each toward the score of both jurisdictions.

Nationally, the District and Arlington/Alexandria score favorably. The DC Metro stations by themselves fall just behind Chicago and Boston.

Unfortunately, Fairfax and Prince George's fall to the bottom of the pile. Fairfax's low score is somewhat understandable since it has only 5 stations, most of which serve mainly as park and rides.

But Prince George's has 15 stations, more than any other jurisdiction aside from the District. The county is at a disadvantage because of the placement of many stations. But even so, Prince George's has not committed to transit-oriented development around its stations. It also has a history of allowing development on the fringes of the county to short-circuit demand for offices and retail near Metro.

Fairfax, on the other hand, is working to reinvent Tysons Corner as a walkable urban place around 4 new Metro stops. Interestingly, adding the 5 stops on the Silver Line already under construction would raise Fairfax's average to 61.8.

While Walk Score is not a perfect measure of walkability, the fact that Tysons already has some pretty good scores bodes well for efforts to transform the employment center into a bona fide urban center.

I analyzed the 11 heavy rail systems in the United States. Some of these cities also have light rail, commuter rail, or other transit systems, but I didn't count those. That means in Boston, I looked at stations on the Red, Blue, and Orange lines, but not Green. (Why?)

I also combined heavy rail stations from multiple operators in the same region. For example, the Philadelphia score counts both SEPTA and PATCO heavy rail stations. New York's includes PATH and the Staten Island Railway (SIRT).

And the winner is... Los Angeles?

I was surprised by the results. Los Angeles scored the highest! I certainly did not expect that. Though in hindsight, it makes a good deal of sense.

Los Angeles has only 2 heavy rail lines, the Red and Purple lines. Those lines are confined to a relatively small area in the LA Basin, with the exception of 2 stations on the Red Line in the San Fernando Valley. And while Southern California has a reputation for being sprawling, the LA Basin is actually fairly dense, especially where the Metro has been built. As a result, its score isn't dragged down by suburban park and ride stations.

In the same respect, I was surprised that BART scored better than WMATA. Large portions of the DC system serve areas that are urban or urbanizing. In contrast, BART's system is much more suburban-oriented and has very little in the way of urban circulation.

Also surprising is that New York is not an outlier. It does come in a close second to Los Angeles, but I really expected it to be off the charts compared to everyone else. The New York City Subway alone scores 90.47 without PATH and SIRT, still just below LA; SIRT averages 71.45 while PATH is higher, 92.23, but its relatively small size (13 stations) means it doesn't change the New York average even a tenth of a point.

What is not very surprising is that the sunbelt cities (except LA) score more poorly than the more urban older cities (except for Cleveland). Cleveland is at a disadvantage because of the structure of its transit system. The system only has one stop in the central business district, and that station's score isn't that impressive anyway, which harms the average.

Distribution matters

The chart above shows how Walk Scores for stations in each system are distributed. The green bars give the average score. The rectangle shows the 25th and 75th percentiles, and the lines with dots at each end show the highest and lowest Walk Scores for any station in that system.

At the high end, several cities had at least one station (sometimes several) with perfect 100-point scores. The lowest score for any station nationwide was 28 points. Two stations in the Washington region—Arlington Cemetery and Morgan Boulevard—and one station in San Francisco—North Concord/Martinez—had that score.

The distribution is important in understanding how well distributed the well-scoring stations are in the system.

In Washington, the distribution is weighted more toward good-scoring stations, but there are still a lot of poor-scoring stations, too.

Compare that to San Francisco's BART, where there are fewer poor-scoring stations. Instead, there are a large quantity of stations in the middle of the distribution.

New York and Cleveland offer contrast to each other. While most New York stations score very well, Cleveland's don't rank above medium.

Limitations

The Walk Score algorithm is not perfect. It works by calculating the quantities and distances of various amenties. There are other factors which it does not measure that help to define the walkability of an area.

For example, a street grid makes an area much more walkable than a sprawling network of superblocks and culs-de-sac. The quality and proliferation of sidewalks also influences walkability. But these factors aren't currently part of Walk Score; there's no good data file for Walk Score to use that shows where there are and aren't good sidewalks, for example.

Regardless, Walk Score gives us a standard and fairly good measure to compare transit stations (and systems) to each other.

The site also features custom commute reports, allowing users to compare their commutes by foot, bike, transit and automobile. Using data from real estate website Zillow and the Center for Neighborhood Technology's Housing+Affordability Index, these commute profiles allow users to see how much of their monthly budget they can expect to spend on combined housing and transportation costs. The real estate search site ZipRealty has integrated these scores into all of their listings.

By providing these tools to a mass market looking for real estate, knowledge about the relationship between location and transportation can become more easily accessible. You don't have to be an urbanist - or the resident of 1600 Pennsylvania Avenue - to make the connection between transportation and the bottom line.