upzoning existing stock- all jurisdictions

[sstrochak]

From the California study:

Our estimate takes into account the characteristics of land surrounding each of the 1,095 transit stations. We filtered out regions classified as rural or remote that are thinly populated and unlikely to be developed for transit-oriented housing over the next 50 years. Within each station area, we screened out non-developable land and assumed that one-third of developable land will be used for commercial purposes. On the remaining land—developable residential space—we assumed that 10 percent would be needed for roads and other public spaces rather than homes. We calculated the housing potential on developable residential land by assuming two scenarios. In our low case, there is one new housing unit per net acre for every 100 existing units within the transit-oriented development area. In our high case, station areas “upshift” to the density of the next urban type. So, suburban nodes (with fewer than 6.5 units per net acre) are developed to the average current density of urban centers, at ten units per net acre. Urban centers (with 6.5 to 15 units per net acre) are developed to the average current density of regional hubs, at 31 units per net acre. And regional hubs (with more than 15 units per net acre) upshift to 31 units per net acre if they are currently below that density, and if they already have more than 31 units per net acre, we use the station area’s low-case density potential. To avoid double-counting the transit-oriented development housing opportunity with other tools discussed in this paper, we subtracted opportunities in transit areas that were identified for potential infill on vacant land (Tool 1) or redevelopment of underutilized land (Tool 4).

A few questions:

• "Within each station area, we screened out non-developable land" - not sure how they did this
• It's not clear to me if they just treated the entire area as "developable"- without taking into account what was already there. So take the buffered area - 1/3 for commercial use - 10% for roads.
• Grouping the nodes into "suburban", "urban center", and "regional hub" only works on the regional scale, not on a jurisdiction-by-jurisdiction basis. Do we want to combine the data so that we can classify? Alternatively, we can use the same definitions provided in the CA study, but not sure if that will group the nodes correctly.
• How do we deal with buffered zones that cross jurisdiction borders? (another argument for combining the data?)

@lhendey @cdavisurban

[sstrochak]

@lhendey first two columns are actual average density and number of units per node. density_midpoint and new_units_midpoint are if we increase density to midpoint of next group. Min is if we increase to the minimum of the next group. plus10 is if we just upzone by 10%

.cluster	density_residential	number_of_units	density_midpoint	new_units_midpoint	density_min	new_units_min	density_plus10p	units_added_plus10p
1	5.066753	4507.787	20.84403	29525.870	13.14442	16954.123	5.573428	450.7787
2	20.971223	7210.588	39.64081	7873.843	30.66614	4458.732	23.068345	721.0588
3	38.356775	5945.474	70.89407	5479.713	53.93672	2746.891	42.192453	594.5474
4	65.016547	6240.688	142.19417	7306.469	106.28396	3885.223	71.518202	624.0688
5	133.701405	8220.375	247.49518	8545.010	206.12922	5742.869	147.071546	822.0375
6	239.752489	5244.625	0.00000	0.000	0.00000	0.000	263.727738	524.4625

[sstrochak]

@lhendey description of the groups

[sstrochak]

closed with P.R. #106