Consistency is the key to understanding SB 375

At public workshops in California’s major metropolitan areas, regional agencies have been getting residents’ feedback on how their regions should grow as they prepare to create the first round of sustainable communities strategies (SCSs) under SB 375. While it’s critical to engage the public in these decisions, it’s also difficult to know how these land use plans matter. After all, any local government will be quick to remind you that regional agencies don’t have any say over land use changes. Many of the planning experts that I interviewed for our report on SB 375 implementation were unequivocal about what does matter: whether the bill leads MPOs, the regional agencies in charge of implementing SB 375, to channel more transportation dollars toward supporting growth in areas where people drive less through their regional transportation plans (RTPs), the multi-decade transportation plans for which SCSs provide the land use scenario. 

The Air Resources Board (ARB), the state agency that oversees the SCS process, recently released its draft methodology for determining whether an SCS meets regional greenhouse gas (GHG) reduction targets. ARB’s methodology focuses on examining whether the different land use and transportation measures identified in an SCS indeed add up to the GHG reductions specified in the target. This is an important question, but I’d add another, even more important question to the list: do the transportation projects in the RTP support the land use pattern identified in the SCS?

A more succinct way of asking this in transportation-speak is, “is the plan internally consistent?” and RTPs are required to be internally consistent. However, the way that MPOs usually create RTPs doesn’t do much service to the notion of internal consistency. Here’s how it typically works: an MPO creates a land use scenario through a combination of modeling and stakeholder outreach, and this scenario becomes an input in the computer travel model that the MPO uses to analyze transportation investments. This approach accounts for land use’s effect on transportation, and the travel model will show that not a lot of people will use a road or transit line that connects two areas where there aren’t a lot of jobs or housing. However, transportation can also influence land use if people or jobs move to take advantage of new transportation facilities, and this approach is not well suited to analyzing these reciprocal effects, because the land use scenario can’t change once it’s entered into the travel model.

The draft RTP/SCS for San Diego that was recently released by the San Diego Association of Governments (SANDAG), illustrates the problems with this approach to planning. Its land use and transportation elements each reduce GHGs, but they do so in mutually incompatible ways. The SCS calls for substantial growth in neighborhoods that are close to the city of San Diego and are well served by transit, where residents drive less.  Meanwhile, the RTP funds several freeway expansions on the metropolitan fringe, which reduces congestion and leads to more efficient vehicle travel.  The problem is that these freeway expansions will likely induce growth in the suburbs, drawing people and jobs away from the neighborhoods that the SCS targets for growth and undermining the transit investments that are needed to support new development in these neighborhoods.  Many groups, including TransForm, the state Office of Planning and Research, and us here at CREC, picked up on these inconsistencies, and we didn’t need fancy computer models to do it; in fact, the way that SANDAG reports its modeling results seem designed to obscure the fact that the agency isn’t putting its money where its mouth is.  All it took was a little common sense and the time to slog through a rather opaque document. 

And therein lies the good news for ARB, which is currently working to shore up its travel modeling knowledge in preparation for evaluating all of these SCSs: in the short term, examining these plans for internal consistency won’t take a lot of technical work.  ARB simply has to include a discussion of induced growth in its SCS methodology and ask MPOs about how the transportation projects that they fund support the land use pattern identified in the SCS.  In the short and medium term, simple quantitative answers based on the growing number of studies on the economic effects of transportation investments should suffice.  In the long term, ARB and the California Transportation Commission need to outline exactly how they expect travel models to account for induced demand and induced growth.  But what’s really important is that ARB signals to MPOs that it is going to go beyond a thumbs-up-or-down approach to evaluating SCSs and begin to examine whether their transportation investments are consistent with how they spend their money.  After all, these investments are where the rubber meets the road, the transit meets the tracks, and the feet meet the pavement.