§ 3111. Obedience to traffic-control devices.
(a) General rule.--Unless otherwise directed by a uniformed police officer or any appropriately attired person authorized to direct, control or regulate traffic, the driver of any vehicle shall obey the instructions of any applicable official traffic-control device placed or held in accordance with the provisions of this title, subject to the privileges granted the driver of an emergency vehicle in this title.
§ 102. Definitions.
Subject to additional definitions contained in subsequent provisions of this title which are applicable to specific provisions of this title, the following words and phrases when used in this title shall have, unless the context clearly indicates otherwise, the meanings given to them in this section:
"Official traffic-control devices." Signs, signals, markings and devices not inconsistent with this title placed or erected by authority of a public body or official having jurisdiction, for the purpose of regulating, warning or guiding traffic.
So you didn't make a left turn from a lane clearly marked by a "traffic control device" for a left turn! Signs, signals, markings and devices not inconsistent with this title have the same effect as far as that statute is concerned in that they all mandate a certain movement.
You guys in PA can sometimes negotiate for a lesser violation maybe in lieu of a higher fine payment; since I don't see you as having any sort of argument, I would accept whatever deal that may come my way (if one comes along at all)!

