And if they are not free to do so then the situation calls for a healthy dose of capitalism.
They should be working for those who pay them more. If the companies they work for are colluding to fix trucker pay then a strike is proper and good ole' fashioned capitalism.
Adam Smith would be cheering them on. Or more likely taking the companies to task.
No, they should purchase shares in oil royalty trusts or other oil related companies and hedge the price increase.