In roadway design situations involving varying pavement widths,
the only effective way to control the edge of pavement positions is
through the use of Assign Template Point Centerline. This
command assigns centerline (.CL) files to template ID points,
independent of the main centerline, thereby controlling the
horizontal location of the edge of pavement. The assignment
of Template ID points to centerline files (.CL) is stored in
Template Point Centerline files (.TPC). These files are then
used by the Process Road Design and Road Network
commands. The slope to these template points is based on the
parameters defined in Design Template. Subgrades can be made
to follow template IDs if their offset distances are defined not by
distance but by reference to the template ID.
The commands that process Template Point Centerlines such as
Road Network will make the template grades follow the template
point centerlines including along their curves for the output of
the template 3D polylines and road TIN surface. This way Template
Point Centerlines can be used to create rounded medians and
edge-of-pavements that follow alignments that are independent of
the main centerline as shown here.
First you are prompted to create a new Template Point Centerline
file (.TPC), or edit an existing one.
Next the Define Template Alignments dialog is presented, showing
a list of existing Template ID-Centerline assignments. To add a new
assignment, first pick the Set button to set the Reference Template
file (.TPL), then pick the Add button. This brings up the Template
Point Centerline Settings dialog. First, pick a Template
Point Description from the List, which is derived from the
components defined in the Template. Next, pick the Specify
Centerline File button, to choose the file (.CL) to assign to the
Template Point ID. Alternatively, you can use the Screen Pick
button to select a polyline from the drawing that the program will
use to generate a centerline. Finally, specify if this assignment
is for the Left or Right side of the main centerline. Pick
OK. Back in the Define Template Alignments dialog, pick Add
to add another assignment, Edit to edit an existing assignment,
Delete to delete a defined assignment, Report to create a report of
the template point centerline data, or Save to Exit.
Now Process the road design
employing the newly defined Template Point Centerline assignment.
In the Process Road Design main dialog, pick the Template Pt
Centerline button to select the new file (.TPC). You could also
create a new Template Point Centerline file directly from this
dialog box using the Edit button and specifying a new file
name.
Here are two sections along the roadway, illustrating the
varying lane widths on the right side of the main centerline.
They are viewed with the Input-Edit Section File command on the
Section menu.
