Viewing entries tagged
data

Better, Stronger, Faster: Inside the New Revolution in Transit Planning

Comment

Better, Stronger, Faster: Inside the New Revolution in Transit Planning

Pic1.png

This is an adaptation of the material I presented at the US Department of Transportation's Data Palooza event, part the Geospatial Transportation Mapping Association’s Annual Meeting in Arlington, Virginia.  GTFS is the de facto open data standard for transit analyses. Carless in North Tampa

The year was 2004.  I was an undergraduate student at the University of South Florida in Tampa, attending classes full time and working 30 to 35 hours per week.  With rent, food, and transportation, I was just making ends meet.  So I made a bold decision: I gave up my car.  I determined to walk or ride my bike for short trips; and for my regional travel needs, there was always the bus….

Well, sort of.

Bruce B Downs Boulevard at Fletcher Avenue. I walked this intersection fairly regularly while living as a carless student near the University of South Florida. (Google Streetview screenshot)

At the time, there was no Google Transit or any other trip-planning application.  Plotting my bus trips involved staring at a tangle of lines on a map and poring over schedules, and in many cases it was often quite difficult to work out how to get from A to B using the Hillsborough Area Regional Transit (HART) system.  In many cases, trips were impossible or at least felt impossible.

And so it was difficult to meet my travel needs – I often had to bum a ride or just miss out on things. Of course, some of that was to be expected, but I often complained that surely, in a metro of 2.5 million people, I should be able to count on transit to get me and my fellow citizens to more places.  In all my ranting on this subject, I never had any quantitative means for articulating the poverty of my circumstances as a transit-dependent person.

The maps and schedules available on the HART website look much the same as they did 10 years ago, but the agency has used open data products like GTFS to change the way patrons plan trips (HART website).

The Information is Flowing, Even if the Buses Aren’t

Fast forward to today – things look different.  Oh, sure, the trips I could make by transit from my former home adjacent to that sprawling campus set in the auto-oriented wilderness of Tampa's northside neighborhoods are probably not vastly improved, but the information about that setting is.

In the first place, HART now offers a Google Transit trip planning application that makes transit trip-making more intelligible than ever before.  Moreover, they openly share the GTFS files that power the application and inform several emerging data products that essentially analyze the maps and timetables to describe the characteristics of transit service in a particular place in ways that were previously unknowable.

One such data product is the US Environmental Protection Agency’s (EPA) Access to Jobs and Workers Via Transit dataset (AVT).  This dataset is a supplement to the Smart Location Database and is built upon the same data, providing the same level of geographic resolution (census block groups – sometimes referred to as the ‘neighborhood’ scale).  The AVT provides information about how much activity of a given type (jobs, population, housing, low income residents, and low or medium income residents) are reachable by transit from a given place.  These values are then compared to regional totals to articulate what share of a region’s activity is reachable from a specific location within that region by transit.

GTFS data can be extended beyond trip planning applications to create value-added data products that provide at-a-glance analysis.  This example comes from EPA’s “Access to Jobs and Workers via Transit” dataset (AVT screenshot).

The AVT map above provides a lot of information about the place I lived when I took the plunge into the autoless lifestyle.  For example, it tells me that I could only reach about seven percent of the jobs in the Tampa bay region by bus (another layer tells me I could reach about six percent of the area’s population).  Given that I worked across town and had friends in all corners of the city, it was bound to be difficult for me to make this adjustment.

Then I thought, maybe I just lived in a particularly inaccessible area? Sadly, that was not the case. The average value for the entire Tampa-St Petersburg-Clearwater region is about eight percent for jobs (and just four percent for population), so my conditions were pretty close to the mean.

What about my complaint that, for a region of its size, transit in Tampa was underperforming?  I queried the AVT and found that of the 25 CBSAs having populations over two million and sharing at least some GTFS data, Tampa-St Pete ranked 21st in average access to population, 18th in average share of population accessible by transit, 22nd in average access to jobs, and 16th in average share of jobs accessible by transit.   As I thought, Tampa is on the low end of transit accessibility for a region its size.

Tampa’s ranking among 25 CBSAs having populations of 2 million or greater and sharing some GTFS data.

A Few Notes on Interpretation

Despite the statistics cited above, there are some reasons to withhold judgment for the region. The metro level data available in the AVT are difficult to compare across regions due to certain elements of its construction, listed below:

Travel time radius is constant, metro size is variable

In the AVT, activities are considered ‘accessible’ if they are within 45 minutes travel time from the origin.  In a small region, that radius is probably enough to get to a large proportion of the region’s activities, but in a larger area, the urban fabric is just too extensive for a 45 minute trip to cover much of that area.  So we have to take care in interpreting these values, especially looking across different metros areas.

In some places, transit serves multiple CBSAs

According to the AVT, from my current home in Durham, NC, I can reach about 23 percent of the jobs in the Durham-Chapel Hill CBSA.  However, that number includes employment in the adjacent Raleigh CBSA.  This is because these regions are linked by Triangle Transit’s express bus service.  So the numerator for my home block group isn’t consistent with the denominator, and this is something to bear in mind when working in an area that abuts another region having overlapping transit service.

GTFS data is not universally available

Finally, not every agency is using GTFS, and a large number of those that do use it are not sharing that information on the GTFS data exchange.  If the data was not being shared at the time the SLD and AVT were being developed, the accessibility attributes of a region will be incomplete.

Applications

The point of this post is not to disparage the regional transit providers in Tampa, but to walk through some of the analytical possibilities available through the AVT as well as issue some basic warnings about what to watch for when using that data.  It was neat for me to look at these numbers and relate them to my own experiences, past and present.  Of course, the data can do more than support my anecdotes.

The AVT can help planners and researchers compare places within a given region in terms of the amount of activity (of a given type) that transit can reach from each block group origin. Here’s a comparison of two places in Sacramento that I would otherwise know nothing about (AVT screenshot).

When used properly, the AVT allows us to directly compare the transit accessibility characteristics of various locations in the same region at a glance.  For the reasons noted above, it’s difficult to compare across regions, though it may be possible and useful in some cases.  Beyond this, one of the most exciting prospects for the AVT is analyzing how accessibility characteristics influence travel behaviors and/or land development trends in a region, teasing out new relationships that can help us better understand the value of effective transit service.

Looking Forward

Documentation for the AVT is available here.  In a follow up post I hope to describe some of the other datasets, tools and reports that are leveraging GTFS data to introduce entirely new ways to articulate what transit accomplishes in our communities and how it is performing.

–Alex Bell, Cities That Work Blog

[For regular news and updates, be sure to follow Renaissance on Twitter @CitiesThatWork]

 

Comment

Take Me Way Out to the Ballgame

2 Comments

Take Me Way Out to the Ballgame

Pic1.jpg

Pic1 Ah, spring, when a young man’s fancy lightly turns to thoughts of glove.  And bat, and ball.  And a place to get together with thirty or forty thousand of your closest friends and root, root, root for the home team.  But where should that place be?  And how does that choice, and its ripple effects on other land use and transportation system elements, affect the sustainability of a community or a region?

The Good Old Days Are Now

Source: http://tigger.uic.edu/depts/ahaa/imagebase/chimaps/Chgo1900.gif

The best cities seem to be those that have a mix of public and private sector investments, and while there’s plenty of room for debate about the wisdom of subsidizing private sector entertainment, there’s definitely a historic synergy between an urban ballpark and its environs. The oldest two surviving examples, venerable Wrigley Field and Fenway Park, were transit accessibile from the get-go, but that was practically a necessity in those days to connect them to the rest of their cities.  On Wrigley Field’s (then Weeghman Park) opening day, Chicago Tribune columnist Ring Lardner, noting the park’s location just south of the end of the line at Wilson, wrote wryly that “many of our citizens will today visit the North Side for the first time”.  And Fenway Park, while closer to town, was built on drained swampland (the fabled fens; seems the practice of naming something new for what’s no longer there anymore is also a long standing practice).

Ebbets Field, although smack in the geographic center of Brooklyn, was also at the periphery of the borough’s developed area when it was built and included the site of a garbage dump called Pigtown.  And the fact that the local club was known as the (Trolley) Dodgers demonstrates that today’s concern for safe, multimodal, complete streets is really also nothing new.   (Amazing how transportation infiltrates sports names:  Trailblazers, Spurs, Mariners, Pistons, Flyers, Jets, Supersonics, and arguably the Pacers and Colts as well just among the big four major leagues.)

Source: http://chibdm.tumblr.com/post/23096720752/trolley-passing-by-ebbets-field-in-brooklyn-new

The Dodgers’ move from Ebbets Field to Los Angeles in 1958 was a symbol of the transportation revolution engendered by the jet age, shattering the outer limits that had been marked by that famous southwestern outpost called Saint Louis.  The new Dodger Stadium also marked the beginning of the movement of stadiums from downtown (or at least arguably urban) neighborhoods to sprawling complexes where the parking and noise associated with special events wouldn’t be thought of as so annoying to the neighbors.

But times change. Los Angeles is now known less as the kingdom of sprawl and more for its high population density (even when considering population-weighted density as opposed to average metro area density).  And Dodger Stadium is now part of baseball’s old guard; the third oldest Major League Baseball (MLB) park after Fenway and Wrigley.

Not all the cookie-cutter stadiums of the ‘60s and ‘70s were out in the ‘burbs, but even those with an in-town address like Fulton County, Veterans, and Riverfront, really only boasted a skyline view – and that was only from the parking lot or the topmost row. Then the pendulum swung back to retro stadiums with a placemaking element beginning with Camden Yards in Baltimore’s Inner Harbor.  Many of the new stadiums are built adjacent to their predecessors, but are nonetheless viewed as a redevelopment anchor.  But Coors Field, AT&T Field, Target Field, Petco Park, and Nationals Park are all examples where baseball was introduced within an urban fabric in or near the city center.  And hopefully the linkage between baseball and transportation planning has been strengthened by the relocation of the United States Department of Transportation to their New Jersey Avenue headquarters a couple blocks to the east of the Nats’ ballpark.

Do You Have to Park at the Park?

Our oldest ballparks are still located along their legacy transit lines.  For the newer parks, it’s a pretty mixed bag.  Not surprisingly, if you want to attract fans to use transit, it helps to be centrally located in a major metro area.  In 2007, Dan Boyle and Tom Larsen examined transit access and use at the 30 MLB parks.    At that time, the championship went to the brand new Nationals (36 percent), with strong showing from other teams in centrally-located homes, including the Yankees and Mets (both at 27 percent), the Cubs, Red Sox, A’s and Giants (all at or above 20 percent), and the Cards, Jays, Padres and Twins (above 14 percent).  About a third (12 out of 30) of the teams have less than 1 percent transit mode share.

Brave Consequences

Pic4

But being near downtown and near transit may not be enough.  In Atlanta, the decision of the Braves to abandon their second stadium near downtown since moving from Milwaukee fifty years ago has generated a wide range of reactions; with even commentators sympathetic to the business decisions faced by team ownership lamenting the abandonment of a central location and the apparent public/private consensus that a stadium lifespan may now be considered only 20 years long.  In this case, a big question for Atlanta is whether or not the departure of the Braves will create a revitalization opportunity in the Summerhill neighborhood that the stadium site (and its demand for parking) never catalyzed.

One of the Braves’ stated reasons for the move is to get closer to their suburban fan base, indicated by a dot map of season ticket holders.  This map has served as an interesting Rorschach test; one can arguably suggest that the new stadium site would reduce total vehicle miles of travel, which is a key goal of balancing land use and transportation.  But it raises the interesting question of whether an improved geographic match between a product and its customer base is better for society when fiscal and social considerations are included.

Rebalancing the Books

Switching from backstops to backboards, major league sports are also moving the ball forward regarding the evolution of transportation and land use planning in California.  The amendment to the California Environmental Quality  Act (CEQA) implemented by SB 743 allows jurisdictions to rethink the definition of transportation impact in transit-oriented or infill development.  SB 743 was passed with the intent of streamlining the development of a new downtown arena for the Sacramento Kings.  In this case, an analysis of the Kings’ fan base indicating that the new downtown site would result in a 20 percent reduction in Vehicle Miles Traveled (VMT) was a key element in helping win public support.

Professional sports is big.  It’s big business, big politics, and a big part of regional pride.  The big issues associated with developing a sports venue aren’t really new, although the details keep evolving.  In fifty years, we’ll have a new perspective on baseball in Atlanta and basketball in Sacramento.  What do you think we’ll be thinking then?

–Dan Hardy, Cities That Work Blog

2 Comments

Outcomes and Outputs

1 Comment

Outcomes and Outputs

vlad1.jpg

vlad1I took the above photo of a disconnected crosswalk in Hampton, Virginia a couple of years ago.  The photo nicely demonstrates the difference between outputs and outcomes, showing a crosswalk that ends up a few feet to the left of the new depressed curb that was built.  To be fair, perhaps the crosswalk marking program hadn’t yet caught up with the depressed curb construction program and they will one day connect.  Notice, however, that the pedestrian who is actually crossing doesn’t trust either the curb depression or the crosswalk but is striking out on his own. How does this demonstrate outputs versus outcomes?  An output is simply a quantity of goods or services produced by an individual, a business or an agency.  An output measure in this case could be defined as the number of crosswalks marked or the number of curbs depressed to meet ADA standards.  Let’s say a transportation agency had a performance measure of the number of new crosswalks installed in a given year.  This would be an example of an output measures.  An outcome, on the other hand, is the ultimate goal or purpose towards which we strive.  If this same transportation agency had instead a performance measure of the reduction in pedestrian accidents at intersections, then this would be an example of an outcome measure.  It would measure progress toward an ultimate goal such as pedestrian safety, but it wouldn’t measure anything that is actually produced by the agency.

A Matter of Control

In the realm of performance based planning and programming (PBPP) the key difference between output and outcome measures can become confused.  The main functional difference in this context is that outputs are within the realm of control of the agency, whereas outcomes are beyond the full control of the agency.  The classic example is in the case of safety.  If safety is the goal of the agency, then some of the outputs that the agency may control to meet that goal might be things like the number of road miles repaired or the number of crosswalks added.  However, there are other factors that influence safety that are not totally within the control of the agency.  To name a few, driver attention, skill or weather conditions are totally outside the control of a transportation agency and yet they influence overall safety.  Therefore, measures such as the number of car accidents or pedestrian injuries are really outcome measures since they include factors that are beyond the agency’s control, whereas measures such as roads repaired or crosswalks installed are output measures since they are wholly within the control of the agency.  The chart below illustrates some examples of output versus outcome measures for transportation:

vlad2In God we trust, all others bring data (W. Edward Deming)

The world of transportation planning nowadays is positively drenched in performance measurement.  With the passage of MAP 21, USDOT will now be establishing a set of performance measures for implementation by states and MPOs in the spring of 2014, and we can all anticipate greater prominence of performance measurement in funding and policy decisions.  In transportation planning, confusion among output and outcome measures can result in a lack of connection between policies and their desired results.  As some have pointed out, this confusion can often be complex and hard to sift through.  For example, should TOD be expressed as an output measure (increase in square footage of development around transit) or an outcome measure (greater economic vitality as a result of transit expansion)?  In either case, an awareness of the key difference between outputs and outcomes will help planners avoid obvious pitfalls.  We can at least learn to distinguish between measuring an output such as the number of crosswalks as something we can control, versus measuring an outcome such as overall safety as something we can only influence but not fully control.

–Vlad Gavrilovic, Cities That Work Blog

1 Comment