Tennessee Code Title 67. Taxes and Licenses § 67-3-902

All funds from the increase in taxes imposed by chapter 931 of the Acts of 1986, and allocated to the state highway fund shall be placed in a separate account and, to the extent not required for the projects provided for in chapter 931 of the Acts of 1986, shall be invested pursuant to § 9-4-603, with the investment income credited to the highway fund.