(a) No person shall operate a vehicle over any bridge or other elevated structure constituting a part of a street at a speed which is greater then the maximum speed that can be maintained with safety to such bridge or structure, when such structure is posted with authorized signs stating such maximum speed. Such signs shall be erected and maintained at a distance of at least 100 feet before each end of such structure.
(b) Upon the trial of any person charged with a violation of this section, proof of the determination of the maximum speed 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.
(c) Except as otherwise provided in this subsection, 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.
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 Section 303.991 of the Traffic Code.