Problems arise when there's not a human around to intervene, such as at unmanned tollbooths, train station ticket kiosks or self-serve gasoline pumps.

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The attacks have spawned long lines at gasoline pumps.

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It would merely highlight the impossible task of squaring the circle of cheap U.S. gasoline at American pumps and strong international pressures against Iran.

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CNN's Christine Romans explained that a lot of the closed gas stations simply don't have electricity to operate their pumps, while others cannot get gasoline delivered to the station from the refinery because of blocked roads or other logistical problems created by the storm.

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Shoppers were polite but tense as they sought food, water and gasoline from stores where shelves were quickly emptied and pumps soon ran dry.

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The pumps can dispense varying mixtures of ethanol and gasoline, allowing motorists to use higher ethanol blends than now used.

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