Archive for the ‘Accessibility’ Category

Garden Variety Links

August 31, 2009

Garden Cities – Suburbs, back to the future…

Christopher, in the comments of my post on the American Dream, mentioned this great photo gallery over on Slate from Witold Rybczynski of Forest Hills Gardens, an American interpretation of the Garden Cities of the turn of the century.  Chris notes these Garden City suburbs have all of the principles of today’s New Urbanist communities – transit orientation, sufficient density, mixed uses and mixed incomes, etc.

It’s all about access

Cap’n Transit continues on his campaign for transportation to focus on accessibility over mobility.  The two concepts, of course, are intricately related, but accessibility is the more important paradigm for urbanism and city life:

Last week Grist had a well-sourced article (which came to me via Planetizen, via Portland Transport, via that nicely illustrates how improving access without mobility can get people to drive less. And of course by driving less, we reduce pollution and global warming, increase energy efficiency, and all the rest. In this case, when stores are located within walking distance, people walk more, improving their health as well.

Transportation planners should be willing to acknowledge when there’s a possible non-transportation solution that’s worth considering, especially when they’re dealing with taxpayer money. They should then be prepared to say, “You know, you really need a business development planner. That’s not my specialty, but let me introduce you to Joe, who’s really good at fostering downtown businesses.”

This kind of integration between professional disciplines ought to be the goal.  Of course, that’s easier said than done.  Nevertheless, fostering regulatory environments where such holistic understandings of urbanism, transportation, and the interconnections between them ought to be encouraged.

At the same time, I don’t think we need a complete revamp of the current system – but encouraging these conversations and spreading these concepts amongst the population at large is important for planners and urbanists.

Great Station Architecture

Aaron Renn has a post on the potential of Chicago’s El and other transit systems to be not just good, but great.  At the end of the post, Renn has a great collection of photos from various transit systems around the world – showing off great station architecture and high-minded design.  The gallery is well worth a look.

Within that discussion, Matt Johnson has a fantastic set of posts at GGW on the basic design elements of Metro’s system (part one – underground stations; part two – above-ground stations; part three – other motifs).  Matt lays out the basic elements of Metro’s stations and how they’re both constant yet varied within the system.

When it comes to creating great stations, DC’s immediate opportunity will be on the Silver line.  Discussion in the comments asked about the sole underground station on the new line (at Dulles), but since that station is in the second phase of construction, we don’t have renderings of the architecture – just some basic engineering.  We do have, however, renderings from the stations in phase one – and the comments in part two of GGW’s thread weren’t exactly complimentary of the architecture.

Some photos from the Dulles Metro website:


Tysons Central 123


Tysons Central 7 – interior


Tysons East

In other station news – over in Vienna, Jarrett Walker has a post on station architecture there – focusing on the Art Noveau elements.

While we’re in Vienna…

Jarrett also has some posts on other elements of Vienna’s transit systems.

First, he has a follow up on the city’s overhead wires. Jarrett’s great photos allow the reader to decide if those wires ruin the city or not.  My opinion is that they do not, and they won’t mean the end of the world for DC, either.  That is, once we decide to bring our new streetcars back from the Czech Republic.

Jarrett also notes about the excellent network effects within Vienna’s system – including cross-platform transfers.  Making transfers easy is an important part of a great system – even in DC, plenty of people I know hate to switch lines, especially at off-peak hours when trains run more infrequently.  Jarrett notes:

In talking about transit planning I’m constantly stressing the need to think in terms of interconnected two-dimensional networks, not just the one-dimensional “corridors” that are the focus of so many transit studies.  It’s a hard point to convey because (a) interconnectedness implies connections, also called “transfers,” which people supposedly hate, and (b) networks are complicated and abstract and hard to think about, which is why I’m always trying to create and promote tools for making them simpler.

What’s more, network effects are really hard to photograph.  The closest you can come is a photo of a really smooth cross-platform connection.

A cross platform transfer allows a rider to switch lines by simply crossing the platform to a different train without having to switch levels, as you currently have to do at Metro Center or the other main DC transfer points.  This diagram from Wikipedia shows how a cross-platform transfer works in Hong Kong’s MTR:

Basically, the train lines weave for you – thus the passenger does not have to navigate stairs/escalators to get to a different platform to switch lines.   Each train stops twice in this one ‘station’ – one stop facilitating a transfer to the other outbound line, the second to the other inbound line.

Jarrett also references one of his other posts, where he notes why transfers are good and why we should try to make them easy – they really make the system as a whole function smoothly.


Moving Time

July 30, 2009
Moving boxes by carlaarena on Flickr

Moving boxes by carlaarena on Flickr

Posting’s been light the last couple of days because I’ve been moving from one house to another.  No matter how many times I do it, I still forget what a pain it can be.  Now that I’m finally settling into the new digs, there’s been a whole lot of things worth commenting on posted in the past few days.

First, Richard Layman gave me a link on his blog, noting that we tend to disagree on a couple of things.  Though Richard and I do diverge on a number of issues, I think it’s worth noting that we’d agree on far more topics than not – including the general overall direction for the District and cities in general.   I’d also point out that a trend I notice in blog commenting in general (and many of my comments in particular) is that the truncated nature of the medium tends to focus my comments on one or two ideas from a post, and too often those ideas are critical rather than positive.  That’s the nature of the beast, I guess.

Thanks to Richard for having so much great info on his blog, I appreciate the link.

Poplar Point is a popular discussion item again.  GGW summarizes the development options presented, and Richard Layman chimes in.  Both note that all the options leave a little something to be desired.  One thing none of them have, however, is a soccer stadium – yet.  DC United officials have been chatting with Akridge about property they own, and is apparently still talking to DC officials about Poplar Point – though no one wants to admit anything.

All this stadium talk triggered a response from Noah Kazis at The City Fix.

While it’s good to see the Journal’s real estate blog thinking about neighborhoods rather than just individual sites, this is a common misunderstanding of how stadiums work. They aren’t vibrant providers of economic development; rather, they sit empty most of the time. The D.C. United schedule calls for 30 games a year, only 15 of which will be at the United’s stadium (not including playoffs, exhibition games and the like). That’s not enough to really spark development. While a built-in market of absolutely packed crowds at your sports bar is great for those 15 nights, the rest of the time you’ve got an enormous empty structure that will inevitably be surrounded by at least some large parking lots. That’s not a draw for street life.

First, I want to address a factual item.  DC United’s league schedule only has 15 home games, but DC United plays in several competitions beyond just MLS each year.  Just this past Tuesday I was in attendance at RFK for a game in the CONCACAF Champions League.  DCU also plays in the US Open Cup every year, plus there is also the SuperLiga, international friendlies, and plenty of games between National teams.  RFK will host the US Men’s National Team three times this calendar year, and has already played host to international matches between two non-US nations – drawing good crowds, too.

This issue of the number of games each year often is mis-stated, as most American sports fans don’t have experience with the idea of multiple, concurrent competitions as is commonplace in soccer leagues across the world (including MLS).  Most North American pro sports have their league’s regular season and then the playoffs – and that’s it.  Soccer has a whole lot more on the schedule, and it’s important to note that.

Still, I don’t think this changes the end result of Noah’s analysis.  Stadiums aren’t great for developing streetlife per se, but they can be an anchor to draw in crowds that would otherwise never venture into that part of the city.

I’d also argue that justifications for sports stadiums on pure economic grounds are misplaced from the start.  Sports are an important part of the civic identity of a city, and it’s important for cities to foster that connection.  Going so far as to hand over an expensive stadium on a silver platter (Nationals Park) probably crosses the line, but there’s something to be said for being a “major league” city.  DC United shouldn’t be an exception.

K Street’s transitway plans are moving forward, and not a moment too soon.  The two options at this point:

One option would create a two-lane busway in the center of K Street, leaving three general-purpose lanes on each side. The other option, on the other hand, makes the transitway three lanes, where the third lane lets eastbound buses pass each other in some spots and westbound buses pass each other in other spots. That option also contains a bicycle lane along the length of K Street. While at first glance the plans seem to provide a clear choice between more accommodation for cars versus more for buses and bikes, the difference isn’t that simple. Making a true “complete street” that works for all modes is not easy.

A nice debate emerged in the comments about bike lanes vs. trees vs. transit.  Leaving that discussion of priorities for another day, I’d offer one comment – I’d like to see a plan that can accommodate rail transit and buses on the same transitway in the space at the same time.  Seattle recently started doing this as they converted their downtown bus tunnel to handle both light rail and bus operations:

For any plan, I’d like to know how it could translate to rail in the future.  I would think that having some passing sections might facilitate streetcar, light rail, and bus operations.

Speaking of streetcars, Jarret Walker has a couple of great posts following up on the ‘debate’ between mobility and accessibility.  Also, along the same vein as trying to define the terms we use when discussing these issues, he has a great post about transportation planning in Australia and determining what values people want from transit.

One of the main reasons that skilled and talented people leave the transit industry is the impossibility of meeting conflicting political demands.   For example, I’ve actually seen cases where elected leaders told a transit agency to cut service on high-ridership route A in order to add new service to low-ridership rural area B, and then complained to staff when that change caused total ridership to go down. Obviously, if you move a service from a high-density area to a rural area, you should expect exactly that result. These hard-but-important questions are designed to elicit direction about the real choices that transit requires us to make, so that talented staff feel supported and encouraged as they follow that direction in building and operating the transit system.

This is the core of so many issues with transit, as well as the different emphasis on mobility vs. accessibility – our opinions of transit systems are expressions of value judgments.  Thus, it’s important to try and determine what those values are through the political process so that they can easily be implemented.

It’s similar to the idea of a community expressing their desires and values in a plan, then setting zoning rules to allow most development by-right, rather than the current mish-mash of PUDs, rezonings, variances, and the like.  Determine the values beforehand, rather than in an ad-hoc fashion while each individual case and decision festers.

Infrastructurist has a great interview with IBM’s HSR folks.

Matt Johnson has an intersting analysis of Metro’s ridership patterns.  More on this later, but the post is worth checking out now.

Streetcar vs. bus debate hinges on mobility vs. accessibility

July 15, 2009

Portland Streetcar. Photo by K_Gradinger.

Portland Streetcar. Photo by K_Gradinger.

Advocates and policymakers constantly debate the virtues of different transit modes. Should we build streetcars or BRT? Commuter rail or heavy rail? Each involves technical and cost tradeoffs, but transit advocates often don’t agree. This debate stems from a difference in how people think about transportation. Is the goal to maximize mobility, or accessibility?

Professionals’ precise definitions vary, but in general, mobility refers to the distance or area a person can cover in a period of time. Accessibility is a more qualitative measure about what you can access, not how much ground you can cover. If a given transportation system allows you to easily access your job, a grocery store, and other local retail services within 20-25 minutes of travel time, that site would have good accessibility, even if that 20-25 minute window of time doesn’t allow you to travel very far. Mobility, on the other hand, is transportation for transportation’s sake. It deals only with distances and speeds, and thus, by extension, area covered.

Choosing which concept to focus on affects how land use fits into the debate. Mobility is a pure measure of distance covered, whereas accessibility is more concerned with the ‘what’ than the ‘how far.’ What’s on the land matters a great deal. Increasing mobility usually also increase accessibility: the more area you can cover in a given amount of time, the more uses you can reach. But we can also increase accessibility without actually increasing mobility. In the United States, we have a legacy of designing transportation policy on mobility alone, while ignoring accessibility.

Jarrett Walker observed,

Streetcars that replace bus lines are not a mobility improvement. If you replace a bus with a streetcar on the same route, nobody will be able to get anywhere any faster than they could before. This makes streetcars quite different from most of the other transit investments being discussed today. …

Where a streetcar is faster or more reliable than the bus route it replaced, this is because other improvements were made at the same time — improvements that could just as well have been made for the bus route. These improvements may have been politically packaged as part of the streetcar project, but they were logically independent, so their benefits are not really benefits of the streetcar as compared to the bus.

New streetcars that replace buses do not change mobility. In theory, a streetcar traveling in mixed traffic will have the same mobility as a bus. Jarrett and other bloggers then grapple with mobility versus accessibility and what to measure. Cap’n Transit asks, “Why do we care about mobility?

Interestingly, Jarrett uses Walk Score to count the places, meaning that his mobility takes density into account. That makes it more valuable than simply measuring how many route-miles you have available to you. There was some back-and-forth in the comments about whether streetcars could increase mobility by increasing density relative to a similar investment in buses, but I don’t think there was a solid conclusion.

Jarrett’s response acknowledges the intrinsic value of accessibility, but also notes the limitations of that concept:

The argument is that the number of places you can get to doesn’t matter so much. What matters is how far you need to go to do the things you need to do. In a denser and better designed city, your need for mobility should decline because more of your life’s needs are closer to you. That’s unquestionably true, and I suspect anyone who has chosen an urban life knows that in their bones. …

One puzzling thing about the access-not-mobility argument is that it suggests that much of what we travel for is generic and interchangeable. Many things are. I insist on living within 300m of a grocery store, dry cleaner, and several other services because I need them all the time and don’t want those trips to generate much movement. But I go to a gym that’s about 1500m away because I really like it, and don’t like the ones that are closer. And every city worth living in is packed with unique businesses and activities and venues that must draw from the whole city. A lot of us want more of that uniqueness, less interchangability, in our cities. How is that possible if citizens aren’t insisting on the freedom to go where they want?

This cuts to the core of the tension between mobility and accessibility. In one sense, increasing mobility naturally increases access simply by opening up easy travel to new areas. However, accessibility captures a more complete picture by asking what the travel is for, not just to accommodate it. Streetcar systems and other rail based transit tend to have higher ridership than similar bus systems. This is known as rail bias, the tendency of passengers to ride trains more often than projected based solely on the mobility improvements of a transit line. Might this rail bias actually represent an accessibility bias?

Metro’s history shows us some of the tension between these two concepts. The Orange line includes areas focused on accessibility between Rosslyn and Ballston, while the outer reaches of the line travel longer distances at higher speeds, prioritizing mobility. Of course, a subway presents an inherent increase in mobility over a bus or streetcar anyway, thanks to the grade separation of the subway tunnels. Still, the hybrid nature of Metro’s system shows the different conceptions of mobility and accessibility.

In Zachary Schrag’s The Great Society Subway, he concludes with a quote from a now retired WMATA official involved with the planning of Metro. Before choosing technologies, routes, and levels of transit service, you have to ask “what kind of city do you want?” One of the key arguments in favor of streetcars is their ability to attract transit oriented development in ways that buses cannot. If we accept Jarrett Walker’s assertion that streetcars do not offer a mobility improvement over buses, what about an accessibility improvement? Transportation investments can be powerful forces for attracting and shaping development, and thus improving accessibility by shaping the city.

In determining what kind of city we want, we also have to recognize that different modes of transportation offer different improvements to both mobility and accessibility. Transit system can accomplish both goals, but design choices inherently emphasize mobility over accessibility or vice versa. Every fantasy transit system makes value judgments about mobility versus accessibility. When those systems are the work of one individual, they represent the preferences of that individual’s vision for the city. How should the Washington region balance mobility and accessibility in future transit and transportation planning?

Cross-posted at Greater Greater Washington.