(b) In addition, upon all roadways, any vehicle proceeding at less than the normal speed of traffic at the time and place and under the conditions then existing shall be driven in the right-hand lane then available for traffic, or as close as practicable to the right-hand curb or edge of the roadway, except when overtaking and passing another vehicle proceeding in the same direction or when preparing for a left turn at an intersection or into a private road or driveway.
(c) Upon any roadway having four or more lanes for moving traffic and providing for two way movement of traffic, no vehicle shall be driven to the left of the center line of the roadway, except when authorized by signs or markings designating certain lanes to the left side of the center of the roadway for use by traffic not otherwise permitted to use such lanes, or except as permitted under subsection (a) (2) hereof.