According to a new UC Irvine study, California's approval into law of Senate Bill 375, a measure dubbed by many as the "anti-sprawl" or "global warming" bill, may provide little overall effect in reducing greenhouse gas emissions and fuel consumption.  
 
The study, co-authored by David Brownstone, economist, and Thomas Golob, researcher emeritus with UCI's Institute of Transportation Studies, appears online in the Journal of Urban Economics and is forthcoming in the journal's print edition.  
 
Using data from the California subsample of the 2001 U.S. National Household Travel Survey which tracked housing density per square mile along with miles driven and fuel consumption per household, researchers found that while living in more populated areas did result in a small decrease in household fuel consumption and number of miles driven, the net effect is quite small. According to their findings, a 40 percent increase in urban population density would need to be achieved in order to reduce driving and fuel consumption by only 4.8 percent and 5.5 percent, respectively.  
 
"Such an increase in Irvine would mean that nearly all new development would look similar to multi-story condo communities," says Brownstone, adding that such a scenario is not very likely to play out in the local area.  
 
"The overall impacts of increased residential density are too small to make increasing density a relevant policy tool for trying to reduce vehicle usage or greenhouse gas emissions from residential vehicles," he says.  
 
The full study, entitled "The impact of residential density on vehicle usage and energy consumption," is available online (requires fee for full viewing from non-campus computer).