1 liter of gasoline in Ro costs about 5 RON/1.28 USD.
That means 1 gallon (4.54 liters) costs about 5.8 USD.
Compare that with US gasoline prices of 2.7 USD/gallon.
The difference is given by the extremely high taxation of gasoline in Ro (which is similar to the taxation levels in other EU countries).
Now, in normal EU countries gasoline taxes are used to pay for infrastructure. What will happen when most cars on the roads will be electric? Most likely, a special road tax will be levied.