Notes for Figure 6H-45—Typical Application 4Temporary Reversible Lane Using Movable Barriers

Support:

 

  1. This application addresses one of several uses for movable barriers (see Section 6F.85) in highway work zones. In this example, one side of a 6-lane divided highway is closed to perform the work operation, and vehicular traffic is carried in both directions on the remaining 3-lane roadway by means of a median crossover. To accommodate unbalanced peak-period vehicular traffic volumes, the direction of travel in the center lane is switched to the direction having the greater volume, with the transfer typically being made twice daily. Thus, there are four vehicular traffic phases described as follows:
a. Phase A—two travel lanes northbound and one lane southbound;
b. Transition A to B—one travel lane in each direction;
c. Phase B—one travel lane northbound and two lanes southbound; and
d. Transition B to A—one travel lane in each directionThe typical application on the left illustrates the placement of devices during Phase A. The typicaapplication on the right shows conditions during the transition (Transition A to B) from Phase A to Phase B.

Guidance:

 

  1. For the reversible-lane situation depicted, the ends of the movable barrier should terminate in a protected area or a crash cushion should be provided. During Phase A, the transfer vehicle should be parked behind the downstream end of the movable barrier for southbound traffic as shown in the typical application on the left. During Phase B, the transfer vehicle should be parked behind between the downstream ends of the movable barriers at the north end of the TTC zone as shown in the typical application on the right. The transition shift from Phase A to B should be as follows:
a. Change the signs in the northbound advance warning area and transition area from a LEFT LANE CLOSED AHEAD to a 2 LEFT LANES CLOSED AHEAD. Change the mode of the second northbound arrow board from Caution to Right Arrow.
b. Place channelizing devices to close the northbound center lane.
c. Move the transfer vehicle from south to north to shift the movable barrier from the west side to the east side of the reversible lane.
d. Remove the channelizing devices closing the southbound center lane.
e. Change the signs in the southbound transition area and advance warning area from a 2 LEFT LANES CLOSED AHEAD to a LEFT LANE CLOSED AHEAD. Change the mode of the second southbound arrow board from Right Arrow to Caution.

3. Where the lane to be opened and closed is an exterior lane (adjacent to the edge of the traveled way or the work space), the lane closure should begin by closing the lane with channelizing devices placed along a merging taper using the same information employed for a stationary lane closure. The lane closure should then be extended with the movable-barrier transfer vehicle moving with vehicular traffic. When opening the lane, the transfer vehicle should travel against vehicular traffic. The merging taper should be removed in a method similar to a stationary lane closure.

 

Option:

 

  1. The procedure may be used during a peak period of vehicular traffic and then changed to provide two lanes in the other direction for the other peak.
  2. A longitudinal buffer space may be used in the activity area to separate opposing vehicular traffic.
  3. A work vehicle or a shadow vehicle may be equipped with a truck-mounted attenuator.

Standard:

 

  1. An arrow board shall be used when a freeway lane is closed. When more than one freeway lane iclosed, a separate arrow board shall be used for each closed lane.