Why not hit the nail on the head? The gas guzzler tax only applies to cars, not to trucks. If you want to discourage large, inefficient vehicles, expand the gas guzzler tax to anything with a truck plate. Like minivans and SUVs. In it’s current form, it applies to anything with less than an average of 22.5 MPG. Like the Honda S2000 for instance, but not a Toyota Land Cruiser.
There already is a tax that discourages people from driving inefficient vehicles-- it’s called a gas tax. Gas Hog taxes are obsolete remnants of the days when people just didn’t really think about how much gas cost-- even though at the moment it’s almost cheaper than it’s ever been people are still generally taking fuel economy into consideration when making car-buying decisions.
Plus, does it really make sense penalizing someone who might have a truck that gets driven a few times a year more than someone who makes lots of frivilous trips in a more efficient car? Also in the toy-hauler example, if the occasionally used truck is made prohibitively expensive by the guzzler tax, people are probably going to be more likely to consider a more powerful and less efficient daily driver, which will result in many more miles being put on a less efficient vehicle.
Ok I have a semi gas hog, 15 mpg city 21 mpg highway, I average 5 gallons a week summer and 10 gallons a week winter, including towing my boat 500 miles each way for a 2 week vacation, I ride my bike to work as I can in the summer, so why am I the worse than a person that gets 30 mpg but uses 20 gallons a week?