Defining Clear Standards for Transit-Oriented Development

» A new report attempts to quantify the relative merits of development near transit. What value can this tool bring for planners?

Transportation and land use are inextricably linked. Building a new rail line may expand development; new development may expand use of a rail line. The direct connection between the two makes differentiating between cause and effect difficult to measure. Transportation planners frequently make the argument that a new investment will produce new riders, for example, but whether those riders would have come anyway is not a simple question to answer. There is no counter-factual.

Nevertheless, planners have invested decades of considerable work in the pursuit of transit-oriented development (TOD), under the presumption that clustering new housing, offices, and retail will result in rising transit use and, in turn, reduce pollution, cut down on congestion, and improve quality of life. There remains some controversy about the effectiveness of TOD investments in actually increasing transit ridership, but, at least in my mind, the success of certain areas over others has as much to do with the manner in which developments are designed as the mere fact that there is construction adjacent to a rail or bus station.

For example, the considerable success of Arlington, Virginia in attracting riders to the Washington Metro, as compared to Rosemont, Illinois’ interaction with the Chicago L, is likely due to the fact that the former prioritized walkable construction immediately adjacent to subway stations while the latter put the rail line in the median of a highway, separated buildings from the station by hundreds of feet, and minimized pedestrian amenities. Getting the design of new development around transit right is often just as important as the transit itself in terms of attracting ridership.

If design matters, what has been missing has been a tool that offers empirical insight into the benefits of specific development interventions in terms of their effect on growing transit use. To fill the gap, a new tool for measuring TOD quality has recently been introduced by the Institute for Transportation and Development Policy (ITDP). It holds potential value in terms of defining the appropriate measures for creating effective TOD, but it needs further development to be useful in aiding the creation of best-practice development designs.

The TOD Standard

ITDP’s TOD Standard replicates the BRT Standard the organization finalized this year. Like the U.S. Green Building Council’s LEED, both are scoring systems meant to offer a quick measurement that allows projects to be compared with one another on a variety of relevant criteria.

ITDP argues that this tool allows planners, developers, and the public to assess proposed or existing projects on a wide number of measures. The report aims to identify “what constitutes urban development best practice in promoting sustainable urban transport.” In other words, the goal of the tool is to determine which development projects would do the most to positively expand public transportation usage.

From the perspective of planners who should be actively promoting urban design that increases transit use, the Standard’s recognition of “development that is pro-actively oriented toward, rather than simply adjacent to, public transport” is encouraging. If the system works, it could be an potent way to make the connection between transit and development more explicit and, if used by municipalities or developers to design projects, it could eventually result in expanded ridership.

Best practices are identified across eight design categories — walking, cycling, the transportation network, accessibility to transit, a mix of uses, density, connections to existing employment centers, and changes in parking and road use. Within those categories, 24 criteria can be analyzed individually and then combined into an overall score in which developments rate from -50 (terrible) to +100 (excellent). The tool could be used to determine how well a completed development compares to best practice, or to identify areas for potential improvement.

Testing the Standard’s Effectiveness

ITDP’s tool is designed for large-scale projects within 800 meters (one half mile) of transit stations that implement at least 20,000 square feet of new construction on an area of four or more square blocks. The tool is not meant to measure the TOD effectiveness of existing districts (which are supposed to be included in a future revision of the Standard).

To evaluate just how the tool works, I chose three large TOD projects in East-Coast cities to compare their relative advantages, and inputted project data into the Standard for comparison. The three projects I selected are the Lindbergh Town Center project in Atlanta, which is fully completed (photograph at the top of this post); the NorthPoint project in Cambridge, just outside of Boston, which is partially completed; and the Vienna MetroWest (aka Metro Town Center), outside of Washington, D.C., which is in planning (the plan is just above this section). The latter project is the now down-scaled version of the Vienna plan.* Each constitutes a major development program located immediately adjacent to a transit corridor.

The data that I inputted into into the tool produced the results seen in the following table. As the last row indicates, the MetroWest project scored most poorly, with a rating of 3 out of 100.** Lindbergh did much better, with a score of 39, and NorthPoint best, with a score of 56. It should be emphasized that neither NorthPoint nor MetroWest are completed, so upon actual construction, the final TOD scores could be significantly different.

Evaluating TOD Based on the ITDP TOD Standard

Note: These figures offer a “sketch” computation of each project’s TOD score; the score should be treated as a general figure, not a fully accurate measure of each project’s characteristics. Criterion Potential Points MetroWest, Vienna, VA NorthPoint, Cambridge, MA Lindbergh, Atlanta, GA Sidewalk access 0 -10 0 0 Complete crosswalks 0 -5 0 0 Driveway interference 1 0 1 0 Active frontage 10 1 10 5 Permeable frontage 2 0 1 1 Shade 2 0 0 1 Cycle network 0 -1 0 -3 Cycle parking at stations 2 2 0 0 Cycle parking in buildings 2 ? ? ? Cycle access in buildings 1 ? ? ? Intersection density 2 -10 2 1 Small blocks 5 0 3 0 Prioritized pedestrian connectivity 3 1 1 1 Max walk distance to transit 0 0 -2 0 Avg walk distance to transit 5 5 5 5 Mix of uses 10 10 10 10 Access to food 1 1 0 0 Affordable housing 4 0 2 2 Residential density 10 4 9 7 Non-residential density 5 0 0 0 Connections to existing urbanism 10 0 4 4 Distance to existing jobs 5 5 5 5 Off-street parking 15 0 5 0 On-street parking 5 ? ? ? Total 100 3 56 39

Assessing the Standard’s Value

The tool was simple to use and its results make sense intuitively: Whereas the MetroWest project is poor urban design from the perspective of encouraging transit use, the other two are far more oriented toward the nearby rail stations. Hypothetically, if the projects were all proposed for the same site, the tool would allow decision makers to make a quick quantitative comparison between the designs and identify the best project for public transportation riders. This could offer a clear benefit in terms of, for example, choosing a winning team for the contract to develop a publicly owned site. Rather than rely on “subjective” comparisons of the aesthetics of site designs (a comparison that too often devolves into a question of individual architectural taste), the tool quantifies the physical.

The Standard could also play a useful role in improving the ability of developers to design their new transit-adjacent buildings most effectively by highlighting where plans fall short in comparison with best practices.

Yet, as beneficial as it could be, the Standard does not appear to have been developed with a clear research methodology to back its scoring system. Why is the active frontage criterion worth 10 points, but the amount of shade on nearby streets only worth 2? Perhaps I am wrong, but my sense is that residential and commercial density are the overwhelming influencers of transit use, yet those criteria only account for a quarter of the score. ITDP does not appear to have conducted a real-world analysis to demonstrate whether certain elements are more beneficial in terms of attracting transit use. Rather, the tool seems to have been created using a common sense approach, which is not as good as one might hope for a “Standard” that is explicitly designed to provide an empirical scoring system for measuring TOD effectiveness.

ITDP’s TOD Standard, though, remains a draft; it will be revised over the next year based on public and expert input. It would be beneficial if those revisions attempted to incorporate evidence about the relative effectiveness of the various criteria in terms of growing transit ridership.

Even so, for those who are already familiar with the basic principles of transit-oriented development, ITDP’s scoring system will do little more than reinforce already-acquired knowledge. Every urbanist knows quite well that good TOD requires pedestrian connectivity, a mix of uses, and bike parking — those goals might as well be imprinted on the foreheads of most people trained in planning. At most, ITDP’s guidelines may highlight slight differences between individual projects, but a quick comparison of the site plans of Vienna’s MetroWest and Cambridge’s NorthPoint is enough for most even unexperienced planners to make out which one is designed for transit, and which one isn’t.

So what added value does the Standard bring? Like WalkScore, it provides an “objective” number that can be used by non-planner decision makers to help them determine which projects would best fulfill the policy objective of maximizing transit use. The Standard must be refined, however, to focus on making that number into something that’s genuinely reflective of best practices.

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* I recognize that the Vienna project profiled here may not be the project that is built; the original plan for the site envisioned much higher densities just next to the station. For this comparison, though, I wanted to pick a project that I hypothesized would score poorly using the ITDP tool, and this revision fit the bill.

** Because I could not locate data on bike access to buildings or the area devoted to on-street parking, the documented scores were really out of a total possible score of 93.

Image at top: Lindbergh City Center in Atlanta, from Cooper Carry Architects; below: Revised Vienna Metro Town Center Plan, from Paraclete Realty