The San Francisco Airport Commission and Mayor Gavin Newsom approved a new lease structure on April 15 that provides financial incentives to those car rental agencies that ensure a baseline of rentals of environmentally efficient vehicles.

“Implementation of this aggressive strategy to green SFO’s rental fleet will greatly advance our fleet greening efforts and have a quantifiable impact on our local greenhouse gas emissions,” said Mayor Newsom in a statement.

Beginning in 2009, rental car companies will be offered a voluntary incentive to encourage at least 15 percent of their rentals meet an EPA rating of 17 (or higher). Cars that are included in this range include Toyota Camry, Honda Accord and Ford Focus.

Customers will receive a credit of $15 per transaction if they rent a vehicle with an EPA 18 (or higher) environmental standard. Cars that meet this rating include Toyota Prius, Honda Civic Hybrid, and Nissan Altima Hybrid.

“SFO strives to be an industry leader in sustainability efforts, and I am pleased that we are the first U.S. airport to create business and customer incentives to increase the fleet size and usage of green rental cars,” said Airport Director John L. Martin.

At the end of the calendar year, each rental car company will submit their verified green vehicle transactions. In the event that they meet the threshold of 15 percent, a rental credit totaling 20 percent reduction in the company’s concession fee to SFO will be calculated and applied at the end of the year.

The 15 percent standard for rental car companies to capture was based on SFO research that assessed the availability of the cars in the market. SFO determined that 5 percent-plus increase in the portion of green rentals over the next 24 months (the term of the initial targets) is an attainable goal to move the car rental industry to change the way they are currently managing their fleets. The program will be in effect for two years. It will be reevaluated at the end of 2010 to determine if the targets and incentives need to be adjusted.