(a) No pedestrian or driver of a vehicle shall disobey the instructions of any traffic control device placed in accordance with the provisions of this Traffic Code, unless at the time otherwise directed by a police officer.
No provisions of this Traffic Code for which signs are required shall be enforced against an alleged violator if at the time and place of the alleged violation an official sign is not in proper position and sufficiently legible to be seen by an ordinarily observant person. Whenever a particular section of this Traffic Code does not state that signs are required, that section shall be effective even though no signs are erected or in place.
(b) 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.