884                                LAWS OF MARYLAND                        [CH. 517

constructing, maintaining, repairing and operating such other proj-
ects as are authorized by the Commission pursuant to the provi-
sions of this sub-title including the cost of replacements, renewals
and improvements. Such tolls shall not be subject to supervision
or regulation by any other commission, board, bureau, or agency
of the State. [The tolls and all other revenues] A sufficient amount
of the tolls and other revenues derived from the project or projects
in connection with which the bonds of any issue shall have been
issued, except such part thereof as may be necessary to pay such
cost of maintenance, repair and operation and to provide such
reserves therefor as may be provided for in the resolution author-
izing the issuance of such bonds or in trust agreement securing the
same, shall be set aside at such regular intervals as may be pro-
vided in such resolution or such trust agreement in a sinking fund
which is hereby pledged to, and charged with the payment of (1) the
interest upon such bonds as such interest shall fall due, (2) the
principal of such bonds as the same shall fall due, (3) the necessary
charges of paying agents for paying principal and interest, and
(4) the redemption price or the purchase of bonds retired by
call or purchase as therein provided. The balance of such tolls and
other revenues may be applied to the purposes set forth in clause
(C) and clause (D) of this paragraph if so provided in such reso-
lution or trust agreement. The use and disposition of moneys to
the credit of such sinking fund shall be subject to the provisions
of the resolution authorizing the issuance of such bonds or of
such trust agreement. Except as may otherwise be provided in such
resolution or such trust agreement, such sinking fund shall be a
fund for all such bonds without distinction or priority of one over
another. The moneys in the sinking fund, less such reserve as may
be provided in such resolution or trust agreement, if not used
within a reasonable time for the purchase of bonds for cancellation
as above provided, shall be applied to the redemption of the bonds
at the redemption price then applicable.

(b) Pledge of tolls in payment.—If the Commission shall not
then be prohibited by any federal law, it may charge tolls for the
use of any tunnel, bridge or bridges heretofore constructed and
financed under the provisions of Sections 163 to 181, inclusive, of
this article and pledge such tolls to the payment of any bonds
issued under the provisions of this subheading [, but such pledge
shall not be effectual unless the outstanding bridge revenue re-
funding bonds to the payment of which such tolls are now pledged
shall be refunded by redemption or exchange under the provisions
of Section 137 of this subheading or until the principal of and the
interest on such outstanding bridge revenue refunding bonds shall
have been paid or provision made for their payment]. To the extent
that this section is inconsistent with the provisions of Section 173
of this article, the provisions of this section shall be deemed
controlling.

136. Preliminary expenses.

The Commission is hereby authorized to expend [out of any funds
available for the purpose] from its construction fund such moneys
as may be necessary for the study of any proposed toll project or
projects and to use its engineering and other forces, and the services
of consulting engineers and traffic engineers, for the purpose of