The Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users Act (SAFETEA-LU) requires the EPA to issue regulations for certifying vehicles as "low emission and energy-efficient." The EPA released their proposal today.
In order to qualify for an exemption, the EPA is proposing that vehicles under 8,500 lbs meet both low emission and energy efficient guidelines.
To the EPA, low emission means the vehicle is certified to either the federal Tier 2 bin 5 (or cleaner) or California LEV II emission standards.
To be energy efficient, the vehicle must be a dedicated alternative fuel vehicle or a hybrid that achieves 50 percent or better in-city fuel economy or 25 percent or better in combined city/highway fuel economy when compared to a similar gasoline fueled vehicle. In other words, the Escape Hybrid is compared to the Escape. The Civic Hybrid is compared to the Civic.
Which is why some hybrids do not qualify. As of right now, only the Honda Civic Hybrid, the Honda Insight and the Toyota Prius are allowed in the HOV lane in California. The new rules for who makes the grade (pdf).
Update: CNN has posted their list of vehicles that get passing marks from the EPA:
Only four manufacturers -- Toyota Motor Corp., Honda Motor Co., Ford Motor Co. and Mazda Motor Corp. -- make vehicles that would qualify. A limited number of natural gas vehicles built by Honda and Ford also would meet the standards.
The qualifying vehicles include: the 2004-07 Toyota Prius, 2006-07 Toyota Highlander Hybrid, 2006-07 Lexus RX400h, 2006 Mazda Tribute Hybrid, 2005-07 Ford Escape Hybrid, 2006-07 Mercury Mariner Hybrid, 2003-07 Honda Civic Hybrid, 2003-06 Honda Insight and 2005 and 2007 models of the Honda Accord Hybrid.
Natural gas versions of the 2003-05 Honda Civic and 2003-2004 Ford Crown Victoria would apply, too.
Some of the vehicles that would not qualify include the luxury Lexus GS450h Hybrid, DaimlerChrysler AG's Dodge Ram Hybrid and General Motors Corp.'s Saturn Vue Greenline Hybrid.