EPA will delay proposed greenhouse gas and fuel economy standards for model year 2017-2025 cars and light trucks until mid-November, according to press reports. The agency had originally aimed to issue the proposed rule by Sept. 30.  EPA is working on the standards jointly with the National Highway Transportation Safety Administration (NHTSA).

EPA cited the difficulty of coordinating with stakeholders for the delay:

"We have worked closely with all key stakeholders including the car companies, the state of California, and others as we move toward releasing the proposed rule," NHTSA spokeswoman Lynda Tran said in an email.

"Given the historic nature of this joint rule between EPA and DOT, as well as the necessary coordination with California, it was recently determined that additional time was needed and we expect to issue a proposal for MY [model year] 2017-2025 vehicles by mid-November." (Obama Admin to Delay CAFE Standards Until November, Greenwire (subscription only), Sept. 27, 2011).

According to the same article, California, which has unique authority to set standards more stringent than those set by the federal government, will also delay its own rulemaking timetable in order keep its process aligned with EPA and NHTSA.

"We have committed to issue our proposed regs at the same time the federal government issues its proposal," California Air Resources Board spokesman Stanley Young said in an email. "The federal agencies have indicated they will issue their proposal in mid-November, a six-week delay. This pushes our board hearing date to the end of January."

In late July, EPA and NTHSA announced that it plans to require vehicles to achieve an average 54.5 miles per gallon (mpg) on a fleet-wide basis in model year 2025. The proposal was supported by auto manufacturers and the state of California.

This is the second round of such standards. EPA and NHTSA finalized GHG and fuel economy standards for model year 2012-2016 vehicles on May 7, 2010.