Two airstrikes, the most recent over the weekend, destroy almost 500 tanker trucks ISIS uses to smuggle oil and sell it on the black market. It is estimated the attacks have destroyed roughly half the trucks ISIS uses to bring in $1 million a day in revenues. To avoid civilian casualties, the U.S. planes first dropped leaflets warning the drivers and then conducted staffing runs to scare them away. Previously, a strike would be called off if any civilians were spotted in the area. For these attacks, if there were more than five civilians in the target area the strike would be called off.