The California Air Resource Board has issued a mail-out (PDF) to inform all off-road and on-road engine and vehicle manufacturers of the new requirement to report carbon dioxide emissions measured during the certification emissions tests (via Green Car Congress).
The reporting requirement is applicable to all 2008 and subsequent model year engines/vehicles and does not require any additional emissions tests. Certifying engine/vehicle manufacturers are being asked to include the measured carbon dioxide emissions in their certification applications.
Typically, CO2 emissions have been measured along with criteria pollutant emissions by the testing facilities and used in the emissions calculations. However, until now, the certification application did not require the CO2 emissions to be reported to ARB.