Warnings

For various reasons, not all alignments may meet the constraints applied. In instances where an alignment has not met all of the constraints applied a warning will appear to direct the user to the warning and level of severity. The buttons shown below appear on the Alignment toolbar and activate notifications of cautionary or critical warnings. The abbreviations in the Warning section of the Alignment Summary dialog box are shown in bold italics under the Description field. Cautionary warnings are not shaded in the list below. You can deactivate them in the Alignment tab of the Preference Settings dialog. Critical warnings are shown in the list below shaded in amber.

The warnings mean that the particular characteristic under scrutiny needs to be investigated at the nominated locations. They are not the definitive answer as to whether the route is acceptable or unacceptable.

In the Plan view, the warnings appear as colored bars with white edging on the alignment. In the Profile view, they appear as area bars along the distance axis.

Warning Description

Light amber

Mid amber

Bright red

Horizontal radius

HR

1.1–1.2 times the minimum radius

1.0–1.1 times the minimum radius

Less than minimum radius

Vertical curve

VC

1.1–1.2 times the minimum radius

1.0–1.1 times the minimum radius

Less than minimum radius

Horizontal straight

(Geometric Alignments only) HS

Less than the minimum allowed

Vertical straight (Geometric Alignments only) VS

Less than the minimum allowed

Design grade

DG

0.8–0.9 times the maximum grade

0.9–1.0 times the maximum grade

Exceeds maximum grade

Sustained grade

SG

0.8–0.9 times the maximum grade

0.9–1.0 times the maximum grade

Exceeds maximum grade

Horizontal crossing (Avoid zones)

HX

Intrusion into low priority

Intrusion into medium priority

Intrusion into high priority

Vertical crossing

VX

1.0 m–0.5 m margin

Less than 0.5 m margin

Falls outside the required margin

Drainage

DR

Lower curb is below the natural surface and grade

0.25%–0.50%

0.05%–0.25%

Less than 0.05%

Coordination

HV

Sight distance is less than the specified minimum

Minor change in horizontal radius

Moderate change in horizontal radius

Major change in horizontal radius

Coordination warnings are issued whenever a crest is sharp enough to prevent a driver from seeing an object at the nominated height at the specified sight distance. The decision about whether a change in radius is minor, moderate, or major depends on the value of:

Where:

If the Change value is… the Change is…

less than 0.25 minor

less than 0.50 but greater than 0.25 moderate

greater than 0.50 major

In the following figure, the precautionary warnings show some close approaches to the limiting grades between 6000 and 7200 meters in light and mid-amber. There is an actual design grade warning in red at approximately 6500 meters. The colored bands are clearly visible in both Plan and Profile views:

In the following figure, the blue alignment was optimized in the absence of the culvert zone. Consequently, when a culvert zone requiring 5 culverts per km at a minimum separation of 100 meters (half the nominal mean) was introduced, it was too low and Quantm Desktop software was able to fit only 3 culverts under the road, rather than the 19 required by the length of the alignment in the zone:

When the software is unable to fit sufficient culverts under the alignment in a culvert zone, those sections of the alignment that are more than 200 meters (the nominal mean) from a culvert are designated with a critical warning.

When the alignment was used as a seed for further optimization with the culvert zone activated, the green alignment below was generated:

Next topic: Alignment Summary