Ray LaHood, who once was the federal transportation secretary for President Barack Obama, had some blunt advice for a legislative study committee trying to figure out how the state can pay for repairing its highways and bridges. To keep promoting economic development, LaHood said, lawmakers will have to think the unthinkable: a tax increase to pay for improvements to the state’s infrastructure. “If you’re going to continue to attract business, attract economic development, provide jobs for people that you represent, we have to deal with this infrastructure program,” LaHood said.