Separate the observation from its exchange value
TMH-9 describes visual assessment. TMH-18 defines exchange fields for the resulting condition data. For flexible pavement, CD5.0 Table 5 names the .flx family and section 5.2/Table 13 defines its layout. A file validator can check a represented value without confirming whether the assessor identified the right distress or assigned the right rating.
Our invented source note concerns SYNTHETIC-DEMO-001, lane P1, from 0.000 to 0.200 km on 1 November 2026. It records a surfacing-failure degree of 2 and extent of 2. Those are fixed training inputs, not an engineering judgement about an actual pavement. The authority code WCP is a permitted example code; this material is not a Western Cape authority dataset or endorsement.
Map the two values to their own columns
Table 13 identifies SURFACE_FAILURE_DEG for degree and SURFACE_FAILURE_EXT for extent. In the checked layout they are positions 20 and 21. Its exchange definition allows integers from 0 to 5 for these two fields. Keep the distinction between degree and extent; identical-looking numeric values do not make the columns interchangeable.
The compact view below shows only the fields involved in this example. It is not a complete .flx record. The downloadable fixtures preserve all 89 positions of the selected CD5.0 template, including empty fields and the final positions. The accompanying field map lists every position. Optional blanks deliberately limit this exercise; they do not claim that a full assessment was completed.
ROAD_ID: SYNTHETIC-DEMO-001
START_KM: 0.000
END_KM: 0.200
SURFACE_FAILURE_DEG: 6 ← faulty export; source note says 2
SURFACE_FAILURE_EXT: 2Identify the export error before correcting it
The invalid file contains 6 in SURFACE_FAILURE_DEG. The synthetic source note says 2, and 6 lies outside the field’s 0–5 exchange range. Two separate checks therefore support investigation: the export disagrees with its source and the value is outside the declared domain.
The application’s structural field validation reports RANGE:SURFACE_FAILURE_DEG for the invalid fixture. Correcting that value to 2 produces zero structural errors for the corrected fixture in the reproduced test. The two downloaded files differ only at SURFACE_FAILURE_DEG; all other field positions are retained.
Correct from source evidence and keep the original
For this exercise the source value is explicitly known, so the corrected export uses 2. On a real job, an out-of-range value does not tell you which in-range value to choose. Return to the signed assessment record or responsible assessor. Never replace every invalid rating with zero or a convenient passing value.
Keep the original export, the corrected export, the source note and a correction log. Confirm the adopted manual edition and selected template, then run the applicable checks against the saved file. If the file belongs to a project, inspect the network and alignment results separately.
What this example proves—and what still needs review
This is a reproducible format/range exercise using synthetic files and the selected TMH-18.flx v5-2016 definition. The test checks positional preservation and a declared numeric range. It does not run a real survey, accredit an assessor, verify the source observation, calculate condition indices or establish complete manual compliance.
The correct pairing of degree and extent, completeness of assessment, appropriate segmentation and suitability for a receiving authority require their own evidence. Zero structural errors in this small example are not a certificate of the road’s condition or a promise about every customer template.
Sources and scope
- COTO TMH-9: Manual for Visual Assessment of Road Pavements, Part ACommittee Draft Final, May 2016. §§A.1.4 and A.2 (printed page A-2); §§A.5.3–A.5.4 for assessment quality context.
- COTO TMH-18: visual-condition exchange familiesCommittee Draft 5.0, February 2016. §1.6, Table 5; §5.2, Table 13; §5.3, Tables 14–15; §5.4, Table 16; §5.5, Tables 17–18.
The cited sources describe their own requirements. Practical checklists and examples do not replace the receiving authority’s adopted profile. Platform review and certification are described in the product documentation.
Working templates
These working aids and synthetic examples are not official templates or evidence of complete compliance. Check each file’s stated scope before use.