Maryland Code, Transportation § 24-206

(b)(1) Except as provided in paragraph (2) of this subsection, a local authority may not impose any restriction under this section without approval of the State Highway Administration.

(2) The following local authorities do not require the approval of the State Highway Administration, if they submit to that Administration, at the time of placing any sign under this section, a statement that a structural analysis has shown the necessity for the particular restriction:

(3) The required statement shall recite that the analysis has been performed by a professional engineer experienced in the area of bridge design and shall include the engineer's name, professional engineer's license number, the date the computations were performed, and the date of the last inspection on which the computations were based.

(d)(1) Unless the person has a written permit from the State Highway Administration or the appropriate local authority, a person, whether the owner of the vehicle, the person having charge and control over the vehicle, or an employee or agent of either, may not drive or cause to be driven any vehicle over a bridge or culvert in violation of any restriction imposed under this section.

(2) In addition to any other penalty provided by law, any owner or person in control of a vehicle that is in violation of any restriction imposed under this section is liable to the State Highway Administration or the appropriate local authority for all damages sustained by a bridge, culvert, or highway as a result of the violation.

(3) In the trial of a person charged with a violation of this section, oral testimony of the existence and contents of signs posted as required by this section is prima facie evidence of the validity of the restrictions stated on them.