text: Chapter 14
  necessary, the quartering party changes previously assigned unit locations in the assembly area. The
  quartering party guides the main body into position from the RP to precise locations in the assembly area.
  14-24. The main body of the march column consists of the remainder of the unit, including attachments and
  minus the trail party. The main body is the principal part of a tactical command or formation. It does not
  include detached elements of the command, such as advance guards, flank guards, and covering forces (ADP
  3-90). The trail party is the last march unit in a march column. It maintains communications with the
  main body. The function of the trail party is to recover disabled vehicles or control stragglers during a
  movement. If the trail party cannot repair a disabled vehicle immediately, it tows the disabled vehicle and
  moves its crew and passengers to a secure maintenance collection point along the movement route.
  14-25. During extended movements, halts are necessary to rest personnel, service vehicles, and adjust
  movement schedules. The march order or unit SOP regulates when to take halts. In short motor movements,
  units schedule short halts every two to three hours of movement, and a halt may last up to an hour. Long halts
  occur on marches that exceed 24 hours. When possible, these halts are not to exceed two hours. Units do not
  schedule long halts at night to allow maximum time for night movement. During halts, each unit normally
  clears the march route and moves to a previously selected assembly area to prevent route congestion and
  avoid possible enemy attack. Units establish security and take other measures to protect the force. Unit
  leaders promptly notify commanders of the time and approximate length of unscheduled halts.
  MARCH TECHNIQUES
  14-26. Organized march columns employ three march techniques: open column, close column, and
  infiltration march. All techniques use scheduled halts to control and sustain the road march. The mission
  variables influence the distances between vehicles and dismounted Soldiers. During movement, elements in
  a column may encounter many different types of routes and obstacles simultaneously. Consequently, parts
  of the column may be moving at different speeds, which can produce an undesirable accordion effect. The
  movement order establishes the order of march, rate of march, interval or time gaps between units, column
  gap, and maximum catch up speed. Unless commanders direct them not to do so for security reasons, march
  units report when they have crossed each control point. Units maintain air and ground security throughout
  the movement.
  Open Column
  14-27. In an open column, units increase distances between vehicles and dismounted Soldiers for greater
  dispersion. The distance between vehicles varies from 50 to 100 meters (54 to 110 yards), and it may be
  greater if required. The distance between dismounted Soldiers varies from two to five meters (2 to 5 yards)
  to allow for dispersion and maneuver space for marching comfort. Any distance that exceeds five meters (5
  yards) between dismounted Soldiers increases the length of the column and hinders control. Units normally
  use the open column technique during daylight. They may also employ it at night by use of infrared lights,
  blackout lights, or passive night vision equipment. Using an open column roughly doubles the column’s
  length and thereby doubles the time it takes to clear a point when compared to a close column moving at the
  same speed. The open column is the most common march technique because it offers the most security while
  still providing leaders a reasonable degree of control. In an open column, vehicle density varies from 15 to
  20 vehicles per kilometer. A single infantry company, with intervals between its platoons, occupies roughly
  a kilometer of road or trail.
  Close Column
  14-28. In a close column, units space vehicles approximately 20 to 25 meters apart. At night, vehicles are
  spaced so each driver can see the two lights in the blackout marker of the vehicle ahead. Units normally
  employ a close column for marches during darkness under blackout driving conditions or for marches in
  restricted terrain. This method of marching provides maximum traffic capacity of a route, but it provides
  little dispersion. Normally, vehicle density is 40 to 50 vehicles per kilometer along the route in a close
  column. During dismounted movements, leaders reduce the distance between individual Soldiers to one to
  three meters to help maintain contact and facilitate control.