Baseline TOD Typology Matrix: A Quick Explanation
The TOD Typology Matrix is a baseline measure for analyzing current intensity and use factors for station areas within Los Angeles. to the best use of this matrix is to combine it with individual station sheets with factors specific to those station areas. It is not a standalone tool but rather an integrated part of a station area analysis, in order to see what factors will help that station area meet community established goals and performance measures.
The matrix measures current station area performance on two axes. The vertical axis represents the total of workers and residents in a given half mile radius around each station area (Figure 1). This measure of intensity is one of many factors that are needed to create a good transit-oriented district.
Figure 1: Description of the Typology Vertical Axis
The horizontal axis of the matrix represents the mix of housing and employment in the station area. This shows that stations play different roles in being origin points, destination points, or both, on the transit system (Figure 2). We need both origins and destinations to make the transit system usable and generate riders. Overall, the typology shows that transit station areas, and TOD can and do take many forms in Los Angeles.
Figure 2: Description of the Typology Horizontal Axis
Our cutoffs on the vertical axis are determined based on academic research in 53 international higher income cities*, which shows a correlation between station area intensity, and reduced vehicle miles traveled.
At 7,000 persons per half mile (on the vertical axis), station areas hit a critical point, at which density (plus a lot of other factors) can support frequent transit service, and thus a potential reduction in auto dependency. This is the equivalent to our original cutoff for the lowest category but we have raised the cutoff here. Nonetheless we want to make a note that most stations at least achieve the density necessary to support a reduction in vehicle miles traveled (VMT), even if they don’t meet all the other criteria to be transit supportive.
Stations with 12,000 persons per half mile could potentially achieve a 30 percent reduction in auto dependency (VMT) from the baseline 7,000 persons, and this the cutoff between the bottom categories and the middle categories. Roughly estimated, in a station area with only residential uses this could equate to an increase in gross density of between 5 and 10 du/acre from the baseline.** In a station area with only office uses, this could equate to an additional 1.75 million square feet of office space, or an increase in the gross FAR of 0.75 to 1.0.
At the third level, an additional 30 percent reduction in auto dependency (VMT) could potentially be achieved with 21,000 persons per half mile (9,000 more persons). There is a vast difference in the land uses, amenities, densities, urban design, and transit richness of the station areas achieving at least this level of intensity (for example, the Soto Station just exceeding the 21,000 mark, vs. Wilshire/Western with 59,000 persons). But they all have achieved this important benchmark. Beyond this point, the role of intensity in reducing auto-dependency is much less significant relative to the other factors that contribute to creating places with enhanced walkability and reduced auto dependency . Much more intense stations such as Wilshire/Western offer amply more residents and workers the opportunity to enjoy the benefits of transit-rich environments.
What are the other factors that are playing into reducing auto dependency and generally creating good TOD in LA? This is where we need to take a look at the station area sheets, and understand development opportunity, demographic change, physical barriers, block sizes, community amenities, mix of land uses, and others. The screens and the typology matrix offer a useful and quick tool to assess the current performance of the 60+ station areas, and look for ways to prioritize investments and achieve future improvements.
* Peter Newman and Jeffrey Kenworthy, Cities and Automobile Dependence: An International Sourcebook, Gower Publishing,1989. Persons per acre includes residents and jobs, and is a gross measure over all land area.
** Gross density and FAR includes all 499 acres in a half mile station area, and does not net out space for streets, setbacks, or other necessary amenities.
