According to the driver I was talking too, three things, the administration changed transportation rules making it more expensive and time consuming to transport fuels and other hazmats, they also reduced the number of hours a hazmat driver can drive a day vs a regular semi. Two: they reduced the amounts of oil that can flow via pipelines(not talking about the one he cancelled, but the existing ones) and three, during the pandemic, a lot of truckers left their companies for retail and grocery chains who were paying premiums to keep food and house hold items in stock
