A senior official in the Obama administration held an anonymous background briefing with reporters Monday evening, confirming earlier reports that the administration plans to issue new regulations for automobiles tomorrow.

Given that the official largely confirmed everything that has already been written, it wasn’t entirely clear why anonymity was required, but there you go. The new standard does indeed achieve the same requirement in 2016 as the California standard, although the ramp-up in the first three years is slightly slower. California has consequently agreed to drop its request for a separate standard, at least through 2016.

The proposed rule, to be filed jointly by the Environmental Protection Agency and the Transportation Department, would break vehicles into unspecified categories and require each category to increase in fuel-efficiency. This new system is designed to ensure that all vehicles improve, because companies can’t simply make a few more fuel-efficient vehicles to offset their gas-guzzlers. Manufacturers would still be required to make sure that their entire fleet meets the average of 35.5 miles per gallon.

The official said the new proposal is expected to add $600 to the price of a new car on average, in addition to the $700 increase expected from the previous regulations. But once you factor in savings due to increased fuel efficiency, the official explained, ’it might end up being a wash."

Although the proposal must still negotiate the regular rule-making process, the administration seems confident that it will sail through as written, thanks to support from not only California but also the automobile manufacturers themselves.