The ARB's Draft targets are really a range of GHG reductions resulting from scenarios the MPOs (regional governments) had presented to the ARB. The lower end of this range represents the reductions expected from Regional Transportation Plans adopted before SB 375. The upper end of this range represents the scenarios each MPO thought to be most ambitious.
|MPO Regions||2020 Draft Targets|
|Metropolitan Transportation Commission (MTC) |
Sacramento Area Council of Governments (SACOG)
San Diego Association of Governments (SANDAG)
Southern California Association of Governments (SCAG)
|5 - 10%|
|Council of Fresno County Governments |
Madera County Transportation Commission
Merced County Association of Governments
Kern Council of Governments
Kings County Association of Governments
San Joaquin Council of Governments
Stanislaus County Council of Governments
Tulare County Association of Governments
|Association of Monterey Bay Area Governments |
Butte County Association of Governments
San Luis Obispo County Council of Governments
Santa Barbara County Association of Governments
Shasta County Regional Transportation Planning Agency
Tahoe Metropolitan Planning Organization
Targets are expressed as a percentage reduction in regional per capita GHGs versus 2005 levels. But what do these targets actually mean? How will they translate into policy changes? This all depends on whether or not these targets are too weak, too strong, or just right. The 4 large MPOs with the 5-10% reduction target contain the vast majority of the state's population and vehicle activity. For purposes of this analysis, we'll look at only these MPOs.
The first question to ask is how the absolute level of emissions in 2020 would compare to 2005. The background information on regional VMT, GHG emissions, and population levels the ARB provided the public is denominated in weekday pounds of CO2 per capita. There are some problems with using a weekday number rather than an annual number (leakage to weekends), but I won't elaborate here. Using these figures, we can get an idea of a region's weekday pounds of CO2 in 2005 and what the reduction targets would mean for 2020:
|MPO||2005 AGGREGATE WEEKDAY EMISSIONS (lbs CO2)||2020 REDUCTION TARGET (LOW)||2020 AGGREGATE WEEKDAY EMISSIONS (LOW TARGET, lbs CO2)||ABSOLUTE CHANGE 2005-2020 EMISSIONS||2020 REDUCTION TARGET (HIGH)||2020 AGGREGATE WEEKDAY EMISSIONS (HIGH TARGET, lbs CO2)||ABSOLUTE CHANGE IN EMISSIONS|
One of the things we see here is that even under the 10% scenario, absolute regional emissions will increase. [EDIT: An earlier version of this entry had compared this absolute increase versus Scoping Plan reduction amounts (provided as a placeholder). I had erroneously compared the 2020 projections as if they were versus a 2005 versus 2020 2020 Business As Usual baseline.]
The next step in our analysis is to compare these targets to current greenhouse gas emissions. Unfortunately, I'll have to use VMT as a proxy for CO2. VMT doesn't account for additional emissions caused by traffic congestion, but because reductions in CO2 per mile from vehicle fuel efficiency and low carbon fuels are controlled for in SB 375 reduction numbers, and the state's method to calculate vehicle CO2 also somewhat ignores congestion, it's fine for our purposes. Using VMT by county data from Caltrans, I calculated 2005 and 2008 (the most recent year available) VMT for California's large MPOs. Incorporating population data, I came up with an end result of change in per capita VMT between 2005 and 2008, which will proxy for change in per capita transportation CO2 between those years.
|MPO||2005 VMT||2008 VMT||2005 PER CAPITA VMT||2008 PER CAPITA VMT||PERCENT CHANGE|
From this data, it appears that SCAG, MTC, and SANDAG already achieved their low end 2020 targets in 2008 and SACOG achieved their high end 2020 target. A combination of the economic downturn and higher gasoline prices resulted in a reduction in driving between 2005 and 2008.
However, what we are really interested in is what might happen between 2008 and 2020 that would increase VMT and GHG per capita, if not for a change in regional transportation policy and local land use policies. Renewed economic growth could create more demand for driving (more people going to and from shopping and jobs) and the reductions observed between 2005 and 2008 could be eroded. Additionally, gas prices could decrease and people could respond by driving more. Unfortunately, I can't predict these effects and neither can the ARB or MPOs. What we can predict, however is demographics. In 2020, we know that people will be 10 years older. We also know that older people drive less:
We are learning information that younger people are driving less as well, drive less as well. So, economic factors held constant, we could expect a further reduction in per capita driving in the future, without regions adopting land use and transportation policies designed to reduce travel demand and promote alternative modes to driving. This reduction is not reflected in the SB 375 draft targets.