Don't start dreaming about that downtown loft just yet. 

Though curbing low-density housing may be one key to implementing SB 375 and reducing greenhouse gas emissions, a new Public Policy Institute of California study suggests that the true key to reducing the state's vehicle miles traveled lies in employment density, not residential density. The study, Driving Change: Reducing Vehicle Miles Traveled in California, argues that while the state has taken solid first steps to implement SB 375, the state must reverse some counterproductive trends and consider some innovative, and potentially controversial amendments to SB 375 if it is to fulfill its promise.  

Authored by PPIC researcher fellows Ellen Hanak, Louise Bedsworth and Jed Kolko the study relies on a variety of sources, ranging from government data to interviews with planners and public officials.   

The study notes that "employment density matters more than residential density for encouraging transit use as an alternative to driving" and that cities must therefore make investments and policy choices that promote greater commercial density, coordinated with transit.  The study points out shortcomings in the state's recent approaches to smart growth. For instance, it contends that many recent transit investments have not reduced VMTs and that many transit-oriented developments have failed to reduce traffic because residents of those developments often make ample use of their cars. While rail ridership has increased slightly—from 0.9 percent of all commutes in 1990 to 1.4 percent in 2008—the growth is much slower than the pace of transit cost increases and service expansion. 

The report found that transit ridership is increasing, with recent investments directed toward higher-density areas, where they will be more likely to get people of out their cars. Regional transportation authorities and local governments recognize the importance of integrating land use, transit, and pricing policies such as toll lanes, carpool lanes, and parking fees. And, despite the recession, local governments have increased activities to support the goals of SB 375, and they say the policies they have begun to implement have a strong potential to reduce residents' driving.

The study recommends that SB 375 be amended to specifically promote commercial development around transit. This recommendation contrasts somewhat with some of the more popular tenets of smart growth. In many ways, smart growth promotes an urban lifestyle -- meaning a residential lifestyle. In contrast, increased commercial density hearkens back to the 20th century "doughnut holes" in which downtown areas empty out at night once all the employees have fled via automobile. Driving Change seems to suggest that the doughnut hole should in fact rise again -- but with employees rolling home on steel wheels rather than their own tires. 

The study wades into more controversial territory with its tacit endorsement of pricing tools to influence drivers' behavior. The study claims that pricing tools, such as congestion pricing, tolls, and even a milage tax (instead of a gas tax), could be the most effective means of getting drivers' out of their cars. These tools are, however, the most politically unpalatable and are likely to raise the ire of voters who are both wary of both higher fees as well as government intrusion in their lives.