Governors in cash-strapped states are revving the motor on efforts to hike the gasoline tax to cover shortfalls or pay for transportation projects — frustrating drivers, Republican lawmakers and others in a delicate economy.

The tax hikes mean that drivers could soon be paying more at the pump, even if the price of fuel goes down.

Wyoming and California have already approved increases. Wyoming’s state gas tax goes from 14 cents to 24 cents a gallon in July and is projected to bring in roughly $70 million in fiscal 2014 for transportation projects. And California regulators last month approved a 3.5-cent hike on its state excise tax that will take effect in July and increase the cost of an average fill-up by roughly 52 cents.