Spectra Precision Survey Pro v4.6 Recon and Nomad User Manual - Manual (Page 101)

Road Layout
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segment now take on the shape of the inserted template. The figure
shows a widening where the start width is the same as the end width
but having the widening use the same start and end width is not
required. The first segment of the template will be adjusted to match
whatever the widening says the width of the first segment should be
at the station where the template is inserted.
Also notice in Figure 5 that we have defined a widening with the start
width the same as the end width. This can be a handy tool to use if
you need to widen the road for a relatively long distance but also need
to change the template segments outside the first segment. Using a
widening as shown enables you to use any template to modify the
outside segments while retaining the same roadbed (first segment)
width.
Super Elevations
The examples above show how widenings interact with templates.
Super elevations work with templates in the same way, except
instead of the width of the first segment being modified, the cross
slope for the first segment is modified.