Requirement for using channelizing devices (e.g. cones) to separate traffic from the work area for a work operation

North Dakota uses flaggers with pilot cars on most of its two-lane two-way roadways on paving projects. Crews provide work zone signing at the beginning and end of the paving operation with the Work Zone Ahead, Be Prepared To Stop and Flagger Symbol signs. The flagger stops traffic at one end when the pilot car is bringing traffic the opposite direction through the construction area. Then the pilot car turns around and brings the waiting traffic. This is continued throughout the work day.