Notes for Figure 6H-35—Typical Application 3Mobile Operation on a Multi-Lane Road



  1. Arrow boards shall, as a minimum, be Type B, with a size of 60 x 30 inches. For State highways, the arrow boards shall, as a minimum, be type II, with a size of 72 x 36 inch. Refer to Department of Transportation’s Standard Specifications Section 12­-3.03 for minimum size and type of arrow panels cited above. See Section 1A.11 for information regarding this publication.
  2. Vehicle-mounted signs shall be mounted in a manner such that they are not obscured by equipment or supplies. Sign legends on vehicle-mounted signs shall be covered or turned from   view when work is not in progress.
  3. Shadow and work vehicles shall display high-intensity rotating, flashing, oscillating, or strobe lights.
  4. 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.



  1. Vehicles used for these operations should be made highly visible with appropriate equipment, such as flags, signs, or arrow boards.
  2. Shadow Vehicle 1 should be equipped with an arrow board and truck-mounted attenuator.
  3. Shadow Vehicle 2 should be equipped with an arrow board. An appropriate lane closure sign should bplaced on Shadow Vehicle 2 so as not to obscure the arrow board.
  4. Shadow Vehicle 2 should travel at a varying distance from the work operation so as to provide adequatsight distance for vehicular traffic approaching from the rear.
  5. The spacing between the work vehicles and the shadow vehicles, and between each shadow vehicle should be minimized to deter road users from driving in between.
  6. Work should normally be accomplished during off-peak hours.
  7. When the work vehicle occupies an interior lane (a lane other than the far right or far left) of a directional roadway having a right-hand shoulder 10 feet or more in width, Shadow Vehicle 2 should drive the right-hand shoulder with a sign indicating that work is taking place in the interior lane.



  1. A truck-mounted attenuator may be used on Shadow Vehicle 2.
  2. In high-speed roadways, a third shadow vehicle (not shown) may be used with Shadow Vehicle 1 in the closed lane, Shadow Vehicle 2 straddling the edge line, and Shadow Vehicle 3 on the shoulder.
  3. Where adequate shoulder width is not available, Shadow Vehicle 3 may also straddle the edge line.



  1. For state highways, see Department of Transportation’s Standard Plan T15 and T16. See Section 1A.11 for information regarding this publication.