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
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 such sign.