 He sided with the House majority, 86-47, to adopt a conference report that establishes the minimum value of a motor vehicle, for purposes of sales taxes, as 80 percent of the "standard presumptive value", an amount determined by the Texas Department of Transportation.However, the purchaser may establish a lower value by a valid appraiser.In 2001 the Texas Right to Life Committee rated Representative Nixon a "C+"; his score improved to 113 percent in 2003 and 100 percent in his last regular session in 2005.