 The California Air Resources Board ( CARB ) classified the Volt as Ultra Low Emission Vehicle ( ULEV ) , as CARB tests do not account for the Volt electric range . With all tests conducted under conditions where the engine is running the CARB rated the Volt 's carbon monoxide ( CO ) emissions at 1 @.@ 3 g / mile ( 0 @.@ 81 g / km ) , missing the limit for SULEV classification by 0 @.@ 3 g / mile ( 0 @.@ 19 g / km ) . 
