Even as local officials in Southern California attack the question of how to implement SB 375, they have slyly begun to suggest that the bill isn't the best way to attack the problem it supposedly addresses – greenhouse gas (GHG) emissions. It is not clear what the locals will do with this line of attack, unless they are angling to try to go back to the Legislature to shift the responsibility for GHG emissions reductions away from land use and back toward technological improvements.

The most public attack so far came last week from Ty Schuiling, planning director for the San Bernardino Associated Governments (SANBAG) – a group of local governments that can be expected to be hostile to SB 375's goals. At a conference last week put on by the Leonard Transportation Center at Cal State San Bernardino, Schuiling challenged the idea that land use changes are required to meet the state's GHG reduction goals because the goal cannot be met by making cleaner vehicles, as the California Air Resources Board has suggested. "That is simply not true," Schuiling said.

Schuiling pulled out what he clearly regards as a "smoking gun" on the GHG issue – a letter from the South Coast Air Quality Management District claiming that zero-emission vehicles still must be the weapon of choice against GHGs.

"To achieve federal clean air standards, this region has little choice but to reduce the very GHG emissions targeted by SB 375 to near-zero," the air district's letter to the I-710 Technical Advisory Committee says.  "Clean vehicle penetration far beyond levels assumed by the ARB have been identified as the most likely – perhaps only - way to do it."

Schuiling also noted that different types of cars have different GHG emissions – noting that a 2004 Toyota Prius has half the GHG emissions of a 2004 Chevy Malibu, suggesting that fleet turnover can have a big effect.

A similar but more subtle argument came from Hasan Ikhrata, the executive director of the Southern California Association of Governments, which is charged with implementing SB 375 in the Los Angeles region. Speaking on the same panel as Schuiling, Ikhrata said: "I don't think 375 should be thought of as a global warming bill. I don't think it's the most cost-effective way to reduce GHG emissions. … When I speak about 375 I speak about a land use bill, an urban form bill."

This was substantially the same point Ikhrata made a couple of weeks ago at the SCAG General Assembly in La Quinta, when he rolled out SCAG's "conceptual land use plan". Ikhrata did not deny that SCAG and the region's local governments should pursue a more efficient urban form, but, rather, argued that policymakers should rely less on the idea that climate change is the reason for doing so.

All the powerpoints from the Leonard conference, including my opening keynote speech – which focused on the difference between meeting technical requirements of SB 375 (such creating Sustainable Communities Strategies) and actually creating communities "on the ground" that result in less driving (mostly by concentrating development around transit and parking) – can be found at here.

– Bill Fulton