Just for future reference:

(70 ILCS 3615/4.03) (from Ch. 111 2/3, par. 704.03)
Sec. 4.03. Taxes.
(a) In order to carry out any of the powers or purposes of the Authority, the Board may by ordinance adopted with the concurrence of 9 of the then Directors, impose throughout the metropolitan region any or all of the taxes provided in this Section. Except as otherwise provided in this Act, taxes imposed under this Section and civil penalties imposed incident thereto shall be collected and enforced by the State Department of Revenue. The Department shall have the power to administer and enforce the taxes and to determine all rights for refunds for erroneous payments of the taxes.

(b) The Board may impose a public transportation tax upon all persons engaged in the metropolitan region in the business of selling at retail motor fuel for operation of motor vehicles upon public highways. The tax shall be at a rate not to exceed 5% of the gross receipts from the sales of motor fuel in the course of the business. As used in this Act, the term “motor fuel” shall have the same meaning as in the Motor Fuel Tax Law. The Board may provide for details of the tax. The provisions of any tax shall conform, as closely as may be practicable, to the provisions of the Municipal Retailers Occupation Tax Act, including without limitation, conformity to penalties with respect to the tax imposed and as to the powers of the State Department of Revenue to promulgate and enforce rules and regulations relating to the administration and enforcement of the provisions of the tax imposed, except that reference in the Act to any municipality shall refer to the Authority and the tax shall be imposed only with regard to receipts from sales of motor fuel in the metropolitan region, at rates as limited by this Section.

(c) In connection with the tax imposed under paragraph (b) of this Section the Board may impose a tax upon the privilege of using in the metropolitan region motor fuel for the operation of a motor vehicle upon public highways, the tax to be at a rate not in excess of the rate of tax imposed under paragraph (b) of this Section. The Board may provide for details of the tax.

(d) The Board may impose a motor vehicle parking tax upon the privilege of parking motor vehicles at off‑street parking facilities in the metropolitan region at which a fee is charged, and may provide for reasonable classifications in and exemptions to the tax, for administration and enforcement thereof and for civil penalties and refunds thereunder and may provide criminal penalties thereunder, the maximum penalties not to exceed the maximum criminal penalties provided in the Retailers’ Occupation Tax Act. The Authority may collect and enforce the tax itself or by contract with any unit of local government. The State Department of Revenue shall have no responsibility for the collection and enforcement unless the Department agrees with the Authority to undertake the collection and enforcement. As used in this paragraph, the term “parking facility” means a parking area or structure having parking spaces for more than 2 vehicles at which motor vehicles are permitted to park in return for an hourly, daily, or other periodic fee, whether publicly or privately owned, but does not include parking spaces on a public street, the use of which is regulated by parking meters.

(e) The Board may impose a Regional Transportation Authority Retailers’ Occupation Tax upon all persons engaged in the business of selling tangible personal property at retail in the metropolitan region… [E, F, G deal with the current sales tax.]

(h) The Authority may impose a replacement vehicle tax of $50 on any passenger car as defined in Section 1‑157 of the Illinois Vehicle Code purchased within the metropolitan region by or on behalf of an insurance company to replace a passenger car of an insured person in settlement of a total loss claim….

(i) The Board may not impose any other taxes except as it may from time to time be authorized by law to impose…. [various minutiae of taxing]

[Damn. Here’s the kicker. I had read elsewhere that the RTA could levy a 5% gas tax, as above — and, it turns out, rental car and paid-parking taxes — but apparently cannot levy both the sales tax and the gas tax simultaneously. So, it will take legislative action and not just the RTA board to get that cash. Also covered by Sick Transit.]

(p) At no time shall a public transportation tax or motor vehicle parking tax authorized under paragraphs (b), (c) and (d) of this Section be in effect at the same time as any retailers’ occupation, use or service occupation tax authorized under paragraphs (e), (f) and (g) of this Section is in effect.

Any taxes imposed under the authority provided in paragraphs (b), (c) and (d) shall remain in effect only until the time as any tax authorized by paragraphs (e), (f) or (g) of this Section are imposed and becomes effective. Once any tax authorized by paragraphs (e), (f) or (g) is imposed the Board may not reimpose taxes as authorized in paragraphs (b), (c) and (d) of the Section unless any tax authorized by paragraphs (e), (f) or (g) of this Section becomes ineffective by means other than an ordinance of the Board.