text: Chapter 17
  * Counterattack axis and movement routes.
  * Objectives, future BPs, and avenues of approach.
  17-53. Obstacle control planning is guided by—
  * Supporting current operations.
  * Maximizing subordinate flexibility.
  * Facilitating future operations.
  17-54. Commanders use obstacle control to focus obstacle effort where it will clearly support their intent
  and concept of operations. They also use obstacle control to ensure that obstacles will not interfere with
  current operations or limit their ability to respond to unforeseen situations.
  OBSTACLE CONTROL MEASURES
  17-55. Obstacles can be natural, manmade, or a combination of both. Forces emplace tactical and protective
  obstacles that reinforce terrain restrictions and existing obstacles and integrate them with fires to affect enemy
  movement or maneuver and shape engagements. Obstacle control measures are specific measures that
  grant obstacle-emplacing authority. They consist of—
  * Zones.
  * Belts.
  * Groups.
  * Restrictions.
  The remainder of this chapter discusses these control measure with Figure 17-1 on page 17-12 providing a
  brief summary of each control measure in a single graphic. Commanders with an assigned area can only
  emplace protective obstacles unless authorized by a higher echelon commander.
  17-56. An analysis of the higher echelon headquarters’ mission and commander’s intent identifies
  information that may impact the mission. The components of this analysis are intent, assigned areas, military
  deception, directed and implied tasks, limitations, available assets, risk, and emplacement timelines and risk.
  Among the directed obstacle tasks are the planning, preparation, and execution of reserve obstacles. Reserve
  obstacles allow the force to retain control over the mobility along a given avenue of approach.
  Obstacle Zones
  17-57. An obstacle zone is a division-level command and control measure to designate specific land areas
  where lower echelons are allowed to employ tactical obstacles (JP 3-15). Corps and division commanders
  use them to grant obstacle emplacement authority to brigades (including other major subordinate units).
  Obstacle zones are permissive, allowing a brigade combat team to place reinforcing obstacles to support its
  scheme of maneuver without interfering with future operations.
  17-58. If the obstacle zone encompasses the entire brigade combat team assigned area, another graphic is
  unnecessary. Commanders may designate the entire assigned area as an obstacle zone with the unit
  boundaries defining the geographic limits of the zone. Obstacle zones do not cross brigade combat team
  boundaries. Commanders assign obstacle zones to a single subordinate unit to ensure unity of effort, just as
  they would when assigning defensive assigned areas or BPs. This keeps tactical obstacle responsibility along
  the same lines as control of direct and indirect fires. This does not normally create vulnerabilities on the
  boundary between units since the commander bases the assignment of both subordinate assigned areas and
  obstacle zones on defined avenues of approach.
  17-59. A commander does not normally assign an obstacle effect (block, fix, turn, or disrupt) to an obstacle
  zone. This allows subordinate commander’s flexibility in using obstacles. The commander should establish
  construction and resourcing priorities between different obstacle zones.
  Obstacle Belts
  17-60. An obstacle belt is a brigade-level command and control measure, normally depicted graphically, to
  show where within an obstacle zone the ground tactical commander plans to limit friendly obstacle
  employment and focus the defense (JP 3-15). It assigns an intent to the obstacle plan and provides the