Thursday, May 5, 2011

Five points on California's first draft RTP/SCS

As my colleague Eliot Rose notes in our previous post, the first draft Regional Transportation Plan (RTP) and Sustainable Communities Strategy (SCS) under SB 375 has been released by SANDAG, the San Diego-area metropolitan planning organization (MPO). SB 375 is California’s first effort to link regional transportation planning with land use to reduce greenhouse gas emissions, so many eyes are upon SANDAG’s new draft document as an important trendsetter for implementation of this landmark law.

A number of things leapt out at me on my first read of the document, mostly centering around a key table (Table 2.2 on pages 2-6 and 2-7) comparing performance measure outcomes for the RTP/SCS in 2050, a “no-plan” alternative for 2050, and the present day (defined as 2008 for modeling purposes). SANDAG included many performance measures in this table, but I focused mainly on the core issues of SB 375 and GHG reduction – namely, the CO2 levels per capita, VMT and mode shares. Five points of note:

1. VMT per capita (line 14) is essentially the same in the current-day and RTP/SCS 2050 scenarios, and are only about 5% higher in the no-plan 2050 scenario. This means that plan implementation would do essentially nothing over the next 40 years to reduce per capita driving in the region from today’s levels, and is only marginally better than doing no plan at all.

2. A clear implication of point (1) is that the RTP/SCS is not relying on VMT reductions to meet its regional GHG reduction targets under SB 375 for 2020 and 2035. It does indeed meet those targets, according to Table 3.1 on page 3-3. In fact, according to line 20 in Table 2.2, CO2 emissions per capita drop from 28.1 lbs/day today to 18.9 lbs/day in the RTP/SCS 2050 scenario. Strikingly, however, these emissions also drop to 19.9 in the 2050 no-plan scenario. That is a 29.2% drop in CO2 emissions by 2050 without the RTP/SCS, which is faster than the extrapolated pace of SB 375’s regional targets. (The RTP/SCS would result in a 32.7% decline). This suggests that SANDAG believes it would meet the SB 375 targets without even implementing the RTP/SCS.

3. One possible explanation for how the region will achieve these reductions without reducing VMT is that SANDAG is planning for substantial improvements in avoiding congestion and increasing vehicle speeds. Indeed, these are a major thrust of the RTP/SCS. However, as noted in point (2), most of the CO2 reductions are occurring even in the no-plan alternative, which has much greater congestion than the RTP/SCS scenario (see line 10 of Table 2.2 on page 2-6). It is not immediately apparent within the document how these outcomes square with one another.

4. A background memorandum dated May 14, 2010, and presented in Technical Appendix 9, partially explains how SANDAG developed its SCS/RTP scenario. As part of that process, SANDAG analyzed CO2 emissions for its current RTP, not only for today but for the years 2020 and 2035. That analysis showed that the current RTP will reduce CO2 emissions by 8.8% by 2020 but by only 5.4% by 2035. The memo explains:
Per capita emissions in 2020 are lower than the 2005 base case due to balanced transportation capital investments and balanced growth in jobs and housing throughout the region. However, per capita emissions increase from 2020 to 2035 due in part to a disparity in employment growth and housing growth that begins to emerge after 2020 as employment clusters in the South Bay and North County Inland areas grow more rapidly than housing.
This result shapes much of what appears in the draft RTP/SCS, including the fact that the RTP/SCS scenario achieves 14% reduction of CO2 per capita by 2020, but only 13% by 2035, and just 9% by 2050. This seems to be related to the issues in point (1) and (3) above, as well as the points in Eliot’s previous post. If the RTP/SCS were achieving CO2 reductions through fundamental improvements in the transportation system and regional land use, one would expect these improvements to accumulate over time. But congestion reduction and improved vehicle speed tend to be short-term improvements, which will diminish in effectiveness over time.

5. And that leads to the final point. As many have noted, SB 375 has no strong mechanism for re-shaping regional growth patterns. RTPs plan transportation systems that meet the needs of a given regional land use pattern – a pattern that is determined by disparate local municipalities acting independently of one another. This RTP is no different, even though it includes an SCS and must meet a CO2 reduction target. If local municipalities in the San Diego region continue to make land use decisions that perpetuate sprawl and automobile dependency, there is ultimately little that the RTPs or SCSs will be able to do to make sustained progress against climate change.


  1. One flaw in the Plan's assumptions as suggested in Bill Eisenstein's discussion is that the disparity between employment and housing growth, especially in relation to the employment clusters in the South Bay and North County is somehow responsible for the "lessening" of greenhouse gas emmisions in the later years. I propose that this is erroneous in that "current" commuting patterns suggest that the preponderence of existing long commutes eminate from housing areas in these specific areas of the County and therefore, as employment opportunties increase in these areas, the commutes should be shorter, not longer therefore helping decrease GHG emissions. What I am afraid is that the type of development existing in these specific areas is typical of automobile-centric suburban development, where you have to drive everywhere. Since an increasing number of commuters will thus be remaining closer to home, the future tendency will be for these drivers to actually increase the number of daily trips they conduct within these suburbs, partly due to the "perceived convenience" and partly due the lack of other transit options. This of course assumes that the types of public transit that could help offset these increases are not fully implemented given the current RTP prioritization.

  2. I think they are being realistic in an unstated fashion. As an area grows tremendously in total jobs, half the people will want to stay there or live there, but the other half will want to move away to a more purely residential area to get away from miles of commerce and industry.

    Assuming Escondido goes job-generating, I can't see too many wanting a "new 2035 Escondido urban experience".

  3. Thanks for your comments and for highlighting this issue. My own two cents on this is that the effects of these land use decisions re: jobs-housing balance are themselves another land use decision. In other words, the re-location of jobs to suburban areas will likely induce further sprawl, as swanekj is suggesting, unless localities explicitly plan ahead for this possibility and institute policies to discourage that. A one-hour commute radius around good jobs is much smaller if the jobs are concentrated in the core than if they are distributed in clusters around the region; hence, the pressures for sprawl growth will higher in peripheral areas of the region as jobs spread out.

    This dynamic is partly dependent on the existence of adequate highway infrastructure -- but since the RTP process focuses on solving the transportation problems created by locally determined land use patterns, there is no real planning mechanism by which the transportation investments can leverage smarter growth, rather than the other way around.