Here's an encouraging sign – or rather, billboard: Cruise down the 405 Freeway in El Segundo, California and you'll see a giant billboard with a panel of numbers clicking forward every four seconds, approximating the millions of gallons of gas that have been saved in the U.S. since 2000 thanks to the Toyota Prius [1] and Lexus RX 400h SUV [2] – hybrid-engine vehicles that are selling like hotcakes in America.

Last week, the billboard clicked over to 100,000,000 gallons saved [3] – providing real, motivating evidence to passersby of the positive impact of hybrid technology – oil savings that have the triple-whammy benefits of curbing global warming [3], improving the economy, and weaning America off of Middle East petroleum.

Nearly 300,000 Toyota hybrids are currently on the roads in the U.S. and have managed to offset nearly 900,000 metric tons of carbon dioxide and more than 3 million pounds of smog-forming gases.

Photo credit: Toyota [3]