Tex. Transportation Code § 451.403

(a) The board shall, before an election to authorize a tax, adopt a complete tax code and rules providing for the nature of the tax, the tax rate, and the administration and enforcement of the tax. The code and rules must include provisions for:

(1) the time and manner of payment;

(2) exemptions;

(3) liens;

(4) interest;

(5) penalties;

(6) discounts for prepayment;

(7) refunds for erroneous payment;

(8) fees for collection;

(9) collection procedures;

(10) manner of enforcement;

(11) required returns;

(12) registration and reports of taxpayers;

(13) the duties and responsibilities of tax officers and taxpayers; and

(14) the delegation to tax officers of the power to make determinations and additional rules and obtain records as appropriate.

(b) The tax code and rules may contain other provisions, including the incorporation of other tax laws and remedies for tax administration and enforcement that are available to the state or another political subdivision under general law.

(c) The board, after an election approving the tax, may amend the tax code and rules. The board may not increase the amount of the tax by amendment unless the increase is approved under Section 451.402.

(d) This section does not apply to an authority's sales and use tax or motor vehicle emissions tax.