structures.
Also, do not designate cloverleaf structures as road
junctions.
Making a critical time and point graph can help prevent conflicts and
reduce delays in highway movements. You obtain the data you need for
critical time and point graphs from road movement graphs or road
movement tables. If you need help in reading a road movement graph,
see Appendix B, page 148. This extract of FM 55-30 explains how you
prepare a road movement graph.
You compose a critical time and point graph on subgraphs, one for
each critical point. Mark the four lines of graph for each critical
point with the cardinal points of the compass (north, south, east,
and west) along the sides to show the predominant direction of
movement or change of direction.
Mark the name or number of the
critical point along the left margin.
Place the time of day along
the top on the vertical divisions of the graph in blocks short enough
to show a quarter of an hour or less.
You can show any period of
time--24 hours, 12 hours, or 4 hours--on the critical time and point
graph.
Provide a serial number or other identification of the unit
at each entry.
Each unit preparing for a scheduled move submits a request for
clearance directly to you as far in advance as practical. If time is
available, units must submit a written request for the proposed move.
You must immediately post, by priority, each request on the critical
time and point graph you maintain for the day or days involved. Then
you must confirm or make changes for separation, balance, or
distribution of the requested schedule and route.
Then notify the
originator orally or in writing, depending on time available.
In Figure 2-4, the critical time and point graph contains a subgraph
for each of three critical points (25, 26, and 27).
The horizontal
blocks in each subgraph are lettered N, S, E, W to indicate the
direction in which a convoy is moving. The vertical lines represent
time and are in divisions of 5 minutes.
This figure shows that
serial 225 traveling eastward will arrive at critical point 25 at
approximately 0020 and will clear that point at about 0040.
(Note
that the block containing the serial number extends from the hour of
arrival to the hour of departure.) The subgraph for critical point 26
shows that serial 225 will arrive there about 0130, traveling
eastward and turning northward, clearing the point about 0145.
A
change in direction of travel at a critical point is indicated by a
flag extending into the appropriate line on the graph opposite N, S,
E, or W.
The subgraph for critical point 27 shows that serial 226
traveling northward will arrive at the critical point at 0230 and
will clear that point at 0300.
21
TR1009
Previous Page
