Whenever any roadway has been divided into two or more clearly marked
lanes for traffic, the following rules in addition to all others
consistent herewith shall apply.
1. A vehicle shall be driven as nearly as practicable entirely within
a single lane and shall not be moved from the lane until the driver
has first ascertained that the movement can be made with safety and
then given a signal, not less than the last one hundred (100) feet
traveled by the vehicle, of his intention to change lanes.
2. Upon a roadway which is divided into three lanes, a vehicle shall
not be driven in the center lane except when overtaking and passing
another vehicle where the roadway is clearly visible and such center
lane is clear of traffic within a safe distance, or in preparation for
a left turn or where such center lane is at the time allocated
exclusively to traffic moving in the direction the vehicle is
proceeding and is signposted to give notice of such allocation.
3. Upon a roadway which is divided into four or more lanes, a vehicle
proceeding at less than the maximum posted speed, except when reduced
speed is necessary for safe operation, shall not impede the normal
flow of traffic by driving in the left lane. Such vehicle shall be
driven in the right-hand lane 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.
4. Official signs may be erected directing slow-moving traffic to use
a designated lane or designating those lanes to be used by traffic
moving in a particular direction regardless of the center of the
roadway and drivers of vehicles shall obey the directions of every