Transit Oriented Development should make an effort to increase employment density, if the goal is greater ridership and less car use. Transit Oriented Development should use taller buildings and include office towers, high end retail, hotels, medical centers and so forth. The goal should be to create real centers of activity and employment.
This paper, “Making the Most of Transit: Density, Employment Growth, and Ridership around New Stations”, in particular says that TOD projects should encourage employment density.
“Looking across all metropolitan areas in the United States, those with higher density have higher transit ridership, but the magnitude of the relationship between employment density and transit ridership is twice as large as that between residential density and transit ridership. Furthermore, metropolitan areas where employment is more centralized in downtowns have higher transit ridership, even after taking residential and employment density into account. At the neighborhood level, transit ridership is higher both among residents of a Census tract where tract residential density is higher and among workers in a Census tract where tract employment density is higher. And again, the relationship is slightly stronger for workers and employment density.”
“Connecting destinations to create ridership may seem like an obvious conclusion, but plans and policies have not reflected this approach. Most TOD policy have [sic] focused on residential development, rather than promoting agglomeration of jobs and commercial space in regional centers served by transit”
“Accordingly, employment densities at trip destinations affect ridership more than residential densities at trip origins”
I would point out that Canadian cities with successful transit used TOD for encouraging greater employment density. Many Canadian cities built tall office towers near their transit.
This paper, “New Open-Source Analyses of Transit Job Access and Transit Ridership”, found a very strong relationship between transit ridership and employment density.
“Converting that association into an elasticity, if the number of jobs accessible within 30-minutes were to increase by 1 percent, on average stop-level ridership would increase between 0.6 to 0.8 percent.”
Concentrating more stuff in an area means that more of it is walking distance from transit, but that there is less space for cars.
I would add many places have secondary centers where you have agglomeration occurring, but cars and zoning limit it. You should build transit there and rezone the land to encourage greater agglomeration.