In Detroit last week, the "Raging Grannies," a group of elderly women, sung two songs in support of toughened fuel economy standards at a federal hearing.

In Philadelphia, proponents of the 54.5 mile-per-gallon standard urged officials to implement the Obama administration's proposal, saying it would create jobs, wean dependence on foreign oil and clean the environment.

Next up: San Francisco.

On Tuesday, Jan. 24, the city will host the third and final public hearing hosted jointly by the Environmental Protection Agency and National Highway Traffic Safety Administration on the proposal, which aims for automakers to hit a fleet average of 54.5 mpg by the year 2025.

If Detroit, the home of the nation's auto industry, was an appropriate place to kick off the hearings, then San Francisco is a likely spot for the finale. California has been at the forefront in pushing for a more fuel-efficient U.S. fleet.

State lawmakers considered legislation that would have set a mile-per-gallon standard for cars sold in the state. Automakers worried about meeting varied state-by-state standards, and worked with the EPA and NHTSA to pursue a federal standard.

Although Tuesday's hearing at the Hyatt on Fisherman's Wharf is the final public hearing, officials will still accept comments for the federal register through Feb. 13.

Dr. Mark Cooper, director of research for the Consumer Federation of America, testified the new standard could save U.S. consumers approximately $500 billion at a time when the average American family spent $2,850 on gas last year. He also wrote an op-ed in support of the new rule.

During testimony in Detroit last week, Cooper also said the 54.5 mpg standard is a win-win, saving money for consumers while simultaneously reducing dependence on foreign oil.

"With aircraft carries running around the Strait of Hormuz, everyone has to get that benefit," he said. "Consumers, environmentalists, automakers all support this program. It may be the most important energy program in the past quarter-century."