SB 375 is now law, but another year and a half will pass before the California Air Resources Board adopts the follow-up numerical regional targets for greenhouse gas emissions reductions. This puts California's cities and counties in a pretty big bind: How can they adopt plans for the future that will conform with the climate change law if they don't know what standard they are going to have to comply with?

The new law explicitly states that local plans do not have to conform with SB 375's provisions. But the practical matter is that because transportation funding and housing elements will be tied to SB 375, the locals don't want to get crosswise with their regional planning agencies as they revise old land use plans and adopt new ones. Cities and counties also are trying to handicap SB 375 at the same time that they are trying to comply with the rapidly shifting requirements for dealing with greenhouse gas emissions under the California Environmental Quality Act.

This issue is especially tricky in the six-county region overseen by the Southern California Association of Governments (SCAG), where SB 375 implementation might be downshifted to the subregional councils of government in some instances. In the case of SCAG, not only are the locals unclear as to what the SB 375 targets will be; they don't know who will be creating the plan to reach those targets.

Meanwhile, in Sacramento, the Regional Targets Advisory Committee  (RTAC) – the group charged to come up with the reduction targets and assign them to the regions – is still at the beginning stages of the process.

The RTAC is a 19-member advisory group to the California Air Resources Board (CARB) created under the law to make recommendations on the regional targets. The committee's members include technical experts such as Jerry Walters of Fehr & Peers, regional planning chiefs such as Steve Heminger of the Metropolitan Planning Commission and Mike McKeever of the Sacramento Area Council of Governments, social equity advocates such as academic Manuel Pastor and lawyer Mike Rawson, and political heavyweights such as former Assemblyman Richard Katz.

At a meeting on April 7, the RTAC heard a basic land use/transportation briefing from UC Berkeley planning professor Elizabeth Deakin and began to debate some pretty basic questions – for example, whether targets should be regional or per-capita, and whether targets should be "expressed as an absolute percent reduction or an absolute reduction."

At its subsequent meeting on April 22, the RTAC continued this discussion but went on to some other pretty basic items. The committee debated whether there should be a uniform statewide target that is doled out to the regions or a different target for each region. The committee also discussed how trips between regions should be accounted for in regional targets.

These are all important threshold questions, but they suggest that the RTAC is only starting down a very long road. Under the law, CARB is not required to adopt the regional targets until the fall of 2010. The regional planning agencies then have a year or so to craft a kind of regional plan – known as a "Sustainable Communities Strategy" – that attempts to meet those targets. So, by the end of 2011, the first regional plans will be in place under SB 375.

The League of California Cities succeeded in getting language inserted into SB 375 saying that the law does not usurp any land use authority from local governments. But the law does link the regional plans to both transportation funding and to the housing element process. So most local governments are taking the SB 375 process seriously and struggling with how to conform to plans that don't yet exist.

It's a particular problem for cities attempting general plan updates during the next couple of years. All cities undertaking general plan overhauls are heavily focused on the greenhouse gas issue because of the emerging CEQA requirements. That means they are likely to focus mostly on inventorying emissions and imposing "feasible mitigation measures" to minimize future emissions growth.

That approach may keep Attorney General Jerry Brown happy for the moment, but it is not the same thing as actually cutting emissions, which is likely to be a requirement for at least some regions under SB 375. The new law is based on the assumption that at least some greenhouse gas emissions reductions will have to come from changed land use patterns, which presumably means an overall reduction in vehicle miles traveled.

Localities in California have virtually no experience in trying to figure out how to reduce vehicle miles traveled (VMT). In fact, VMT has never been part of the analytical framework, which has tended to focus on the number of vehicle trips and levels of congestion. So local governments face an analytical problem: how to work VMT into the way they forecast the future of their community.

Beyond that, however, local planners face the problem of not knowing what their VMT reduction target is. Will they have a target? If so, do they have to pay close attention to the target?

On housing elements, the state gives targets to the regional planning agencies and then the regional agencies break those targets down by local jurisdiction. Under SB 375, however, there is no requirement for the regions to give targets to the locals and there is no requirement for the locals to meet targets even if they have them. Targets are translated into sustainable communities plans, which can affect the status of both public and private projects, but not local government plans. Transportation projects must conform with these regional sustainability plans, and certain private development projects get a CEQA break, but there is no explicit tie between the regional sustainability plans and the local general plans.

In the SCAG region, the question of who does the Sustainable Communities Strategy (SCS) is up in the air. Under SB 375, these plans can be done by the subregional COGs in conjunction with the county transportation commissions. But even this arrangement is not as simple as it sounds. Only in San Bernardino County are the subregional COG and the county transportation commission the same entity. In Ventura and Orange counties, the COG and the transportation commission are separate, and in Riverside County there are two COGs and one transportation commission. Los Angeles County has one transportation commission and nine subregional COGs.

Furthermore, the statutory responsibility for the SCS does not automatically downshift to a lower level. SCAG can still do the SCS for the entire region, or, apparently, for parts of the region. To make matters even more confusing, the City of Los Angeles is a SCAG subregion, meaning SCAG could conceivably do a sustainable communities plan for the City of L.A., which, in turn, has no obligation to follow in the city's own planning.

The question of SCSs and general plans will take years to unfold. In the SCAG region, the question of who will do the SCSs should be resolved by around September, so stay tuned. The relationship between SB 375 and general plans is sure to be one of the hottest issues in California planning over the next few months.