(a) Not less than 75% of the annual use of the qualifying vehicle, either mileage or fuel use as determined by the executive director, must occur in Texas.(b) A vehicle or engine replaced under this program must be rendered permanently inoperable by crushing the vehicle, by making a hole in the engine block and permanently destroying the frame of the vehicle, or by another method approved by the executive director that permanently removes the vehicle from operation in this state. The executive director shall provide a means for an applicant to propose an alternative method for complying with the requirements of this subsection.