Gas could hit $4 per gallon this summer, experts say.

Summer travel could become pricey if Americans don’t lose their appetite for gasoline.

Demand is rising at twice the rate of a year ago, according to Bloomberg. Meanwhile, refinery fires, maintenance and electrical failures have reduced inventories to the lowest point in two decades, based on days of demand in reserve.

The upshot is that gas could top $4 per gallon as the summer vacation season emerges, experts say.

Even at $4, consumers might not curtail driving, they say. Americans generally seemed resigned to higher prices.