ADP 3-90, page 52

Chapter 3 3-12 ADP 3-90 31 July 2019  Conduct gap crossing.  Construct and maintain combat roads and trails.  Construct and maintain forward airfields and landing zones.  Conduct traffic management and enforcement. 3-71. Movement and maneuver along multiple axes requires significant coordinated planning and synchronization. Mobility is necessary for the execution of the offense. It mainly focuses on enabling friendly forces to move and maneuver freely. Commanders seek the capability to move, exploit, and pursue enemy forces decisively across a wide front. When attacking, commanders concentrate the effects of combat power at selected locations. This may require a unit to improve or construct combat trails through areas where routes do not exist. The surprise achieved by attacking through an area believed to be impassable may justify the effort expended in constructing these trails. Bypassing obstacles is the preferred method of overcoming obstacles. 3-72. Maintaining the offensive momentum of both armored and Stryker BCTs requires the careful planning and allocation of limited organic mobility capabilities. Maintaining the momentum of the offense requires an attacking force to bypass or breach obstacles as it encounters them. The preferred method of defeating a defended obstacle is by employing a hasty (in-stride) breach because it avoids the loss of time and momentum associated with planning, resourcing, and conducting a deliberate breach. An attacking unit makes a deliberate effort to capture bridges, beach and port exits, and other obstacles intact in order to control their use or destruction. 3-73. Wet (such as a river) and dry (such as an anti-vehicular ditch) gaps remain major obstacles during military operations. Wet gap crossings are among the most complex and risky combined arms operations that friendly maneuver forces encounter. Maneuver units conduct hasty crossings as a continuation of the attack whenever possible because the time needed to prepare for a gap crossing allows enemy forces more time to strengthen their defense. The size of a gap, as well as the enemy and friendly situations, dictates the specific TTP used in conducting a crossing. 3-74. Clearing operations are operations designed to clear or neutralize all mines and obstacles from a route or area. Clearing requires a combined arms force primarily built around engineer and explosive ordnance disposal capabilities. This combined arms team conducts clearing as single missions to open or reopen a route or area. Clearing may also be conducted on a recurring basis to support efforts to defeat recurring obstacles employed along routes and in areas. (See ATP 3-90.4 for additional information on mobility operations.) Countermobility 3-75. Countermobility operations are those combined arms activities that use or enhance the effects of natural and man-made obstacles to deny enemy freedom of movement and maneuver (ATP 3-90.8). The primary purposes of countermobility are to shape enemy movement and maneuver and to prevent enemy forces from gaining a position of advantage. Countermobility supports the conduct of the offense, defense, and stability or defense support of civil authorities across the range of military operations. 3-76. Commanders perform countermobility tasks to isolate objectives and prevent enemy forces from repositioning, reinforcing, and counterattacking to support the offense. These tasks are also performed to provide flank protection and to deny or delay an enemy force’s counterattack as the maneuver force progresses into the depth of the enemy force’s defense. Commanders exploit terrain that offers natural flank protection to an attacking force, such as rivers or ridgelines. Swamps, canals, lakes, forests, and escarpments are natural terrain features that are easy to reinforce for flank security. Units can protect their flanks by denying enemy mobility corridors by building man-made obstacles, such as tank ditches, abatis, or road craters. 3-77. Countermobility during the offense requires rapid emplacement and flexibility. Obstacles deployed in the offense, to include scatterable mines, are normally emplaced by engineers, rotary-winged aircraft, or artillery. Engineers emplacing obstacles must keep pace with advancing maneuver forces and be prepared to emplace obstacles. Commanders consider likely enemy reactions to friendly actions and then plan how to block enemy avenues of approach or withdrawal. They also plan the use of obstacles to contain bypassed enemy elements, prevent enemy forces from withdrawing, and hinder enemy counterattacks.