How record diesel prices will rip through the U.S. economy. Trucks and rails are only the start

Ever since the outbreak of war with Iran earlier this year, motorists have been warily eyeing prices at the pump. While unleaded gas prices have largely avoided historic highs, the same can't be said for diesel fuel , which hit an all-time high of $6.31 per gallon on Wednesday. That was just the latest grim milestone in what has been a steady march upward. Economists and supply chain experts say what starts in the transportation sector , where trucking and rail companies are feeling the pain now — will eventually push prices on virtually everything in the economy up. This is not surprising, because diesel is the economy's single most universal tangible input, said David Russell, global head of market strategy at TradeStation Group.