The California Senate approved a bill over the weekend that is being hailed as the most far-reaching urban sprawl bill in the country. The legislation, which is supported by both the Natural Resources Defense Council and the state’s largest home builders’ lobby, would tie tens of billions of dollars to state and federal transportation funding based on compliance with efforts to reduce sprawl, and by extension, commutes.

Though Gov. Arnold Schwarzenegger has yet to commit to signing the legislation, he has been a major supporter of carbon cutting initiatives in the past. California recently garnered headlines stemming from a lawsuit it filed against the EPA in an effort to enact more rigid emissions standards than those mandated by the federal government. The case is still pending.

Many reasons have been given for why the United States evolved into such a “car culture,” and why it’s been so reluctant to change its transportation habits in light of rising gas prices and global warming. A recent study found that 68 percent of Americans haven’t altered their commutes since the recent price spike began, and that only 7 percent use public transportation.

The simple answer is population density: Of 241 countries measured in a 2004 United Nations study, the US ranked 180th. Americans simply live further away from one another—and their schools, jobs, and malls—making biking, public transportation, and carpooling more difficult than it is in countries like France, England, and Germany.

If California’s legislation is successful, it would lead to fewer permits for developments built on cheap, remote pieces of land, and stimulate more affordable housing closer to city centers. Portland, Ore. has received national attention in recent years for its success in fighting sprawl, and the California bill looks to copy several key components from Portland’s approach.