It also states that the tests include several stops where the car is allowed to idle for relatively long periods of time. The Prius usually ICE shuts off rather than idling, though it will kick back in from time to time, it puts out almost no emissions during this time and skews the results.
The Prius has a bladder tank, it shrinks as fuel is used, so that there is no room for fumes, which helps with the emissions aspect of the car. Aside from the tank not expanding as much when it is cold as it does when it is warm, even under similiar tempature conditions, a full tank is not always the same amount of gas everytime.
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It also states that the tests include several stops where the car is allowed to idle for relatively long periods of time. The Prius usually ICE shuts off rather than idling, though it will kick back in from time to time, it puts out almost no emissions during this time and skews the results. The Prius has a bladder tank, it shrinks as fuel is used, so that there is no room for fumes, which helps with the emissions aspect of the car. Aside from the tank not expanding as much when it is cold as it does when it is warm, even under similiar tempature conditions, a full tank is not always the same amount of gas everytime.