Abstract: An exhaust emission measurement method comprises the steps: —testing a Plug-In Hybrid Vehicle having a combustion engine and an electric motor during a test phase of a predetermined time length; —sampling of exhaust into dilution air; —collecting the diluted exhaust in a diluted exhaust bag, when the combustion engine is operating; —intermittently filling of the bag when a combustion engine of the Plug-In Hybrid Vehicle is operating; —at a certain time before the end of the test phase, changing sampling from intermittent filling to continuous filling of the bag in order to get enough bag volume for an accurate analyzer reading.