The mentally intricate and stresstospheric
process of estimating how much gas there is still in the tank when there is no way to tell for certain because:
A. the fuel gauge does not work
B. it’s reached the point where the tank is so empty, it is pointless to look at the needle for any real information
C. Gastimating may also be resorted to when the gauge does work but there are no more funds for refilling the vehicle
, thus the import of the Gastimate hinges in figuring out as closely as possible how far it may go / how long you may remain in a motor-engine transportable condition with the amount of fuel available. After said combustible liquid is used up, the prior means of transportation magically transforms into a simple sheltering mechanism, protecting against the elements but useless in other ways until gastoration occurs.
Gastimating properly is an essential survival talent
or technique, particularly when driving at night through cities that do sleep and long stretches of empty roads.