(a) (1) No person shall operate a vehicle over any bridge or other elevated structure constituting a part of a highway at a speed which is greater than the maximum speed that can be maintained with safety to such bridge or structure, when such structure is posted with signs as provided in this section.
(2) The Department of Transportation upon request from any local authority shall, or upon its own initiative may, conduct an investigation of any bridge or other elevated structure constituting a part of a highway, and if it finds that such structure cannot with safety withstand traffic traveling at the speed otherwise permissible under this Traffic Code, the Department shall determine and declare the maximum speed of traffic which such structure can withstand, and shall cause or permit suitable signs stating such maximum speed to be erected and maintained at a distance of a least 100 feet before each end of the structure.
(3) Upon the trial of any person charged with a violation of this section, proof of such determination of the maximum speed by the Department and the existence of such signs shall constitute prima facie evidence of the maximum speed which can be maintained with safety to such bridge or structure.
(b) Except as otherwise provided in this division, whoever violates this section is guilty of a minor misdemeanor. If within one year of the offense, the offender previously has been convicted of or pleaded guilty to one predicate motor vehicle or traffic offense, whoever violates this section is guilty of a misdemeanor of the fourth degree. If, within one year of the offense, the offender previously has been convicted of two or more predicate motor vehicle or traffic offenses, whoever violates this section is guilty of a misdemeanor of the third degree.
(c) If the offender commits the offense while distracted and the distracting activity is a contributing factor to the commission of the offense, the offender is subject to the additional fine established under § 408.02.