By increasing car mileage efficiency from 27 to 30 miles per gallon, more than 6 billion barrels of oil could be saved - that's twice the inflated estimates for the refuge.
(more than 6 billion barrels of oil; could be saved; ) Context(more than 6 billion barrels of oil could be saved,List([69, 118))):(that; 's; twice the inflated estimates for the refuge)
more than 6 billion barrels of oil could be saved,List([69, 118))
more than 6 billion barrels of oil that
could be saved 's
twice the inflated estimates for the refuge