TMH 22 explained: the South African road asset management manual

TMH 22 is the South African Draft Road Asset Management Manual of March 2013, compiled under the Committee of Transport Officials (COTO) as a template for a road authority's asset management system (COTO, 2013). It is not a survey method: the manuals that rate and measure pavement condition are separate documents in the Technical Methods for Highways (TMH) series.

Key facts

• TMH 22 is the South African Draft Road Asset Management Manual of March 2013 from the Committee of Transport Officials (COTO), a template for a road authority's asset management system.
• TMH 22 has ten parts, A to J: General and Organisation; Inventory Data; Asset Valuation; Usage and Condition Data; Indices; Situational Analysis; Needs Determination; Asset Management Plans; Feedback Loop; Appendices.
• Part D of TMH 22 states which condition and usage data to collect and how often, and leaves rating and measurement methods to TMH 9, TMH 13 and TMH 19.
• Part E and Appendices J-5 and J-6 of TMH 22 define the deduct-point condition indices and the TMH 22 form of the visual condition index for flexible paved roads.
• TMH 22 never says it supersedes TRH 22, and its "TMH 20" title, Standard for Road Network Data, also appears in the running header of TMH 18 Draft Version 4.
• Draft TMH 22 prints its flexible pavement structure index both as CIPAVE and as CIFPAVE.

What is TMH 22, and what status does it have?

TMH 22 is a draft: its cover reads Draft TMH 22, March 2013. The South African National Roads Agency (SANRAL) published it, and the Department of Transport catalogue lists no later edition (COTO, 2013) (Department of Transport, n.d.).

TMH 22 sets out what a road authority records about each road, how it values the road, which condition and usage data it collects, how those data become indices and how the indices feed plans (COTO, 2013). TMH's sibling series is TRH, Technical Recommendations for Highways.

The synopsis leaves detailed condition assessment to three other manuals. TMH 9 (Committee Draft Final, May 2016) is the South African manual for visual assessment of road pavements. TMH 13 (Committee Draft Final, May 2016) covers automated road condition assessments. TMH 19 (Draft Standard, August 2020) covers visual assessment of road structures such as bridges (COTO, 2013) (COTO, 2016b) (COTO, 2016d) (COTO, 2020b). Each calls itself a companion to TMH 22, which predates these editions, so its pointers name manuals, not clauses.

How are the ten parts of TMH 22 ordered?

The parts run from organisation (A) through data and indices (B to E) and planning (F to H) to feedback (I) and appendices (J) (COTO, 2013).

Part	Title	What it sets out
A	General and Organisation	Legislation, policy, maturity levels, gap analysis, roles.
B	Inventory Data	Network definition, location referencing, asset hierarchy, register fields.
C	Asset Valuation	Current and depreciated replacement cost per component.
D	Usage and Condition Data	Data to collect, how often, quality control.
E	Indices	Condition and functional indices.
F	Situational Analysis	Extent, usage, condition, trends, costs, depreciated values and problem statements.
G	Needs Determination	Need categories, prioritisation, optimisation, treatments, panel inspections.
H	Asset Management Plans	Maintenance strategy, operation plan and maintenance plan.
I	Feedback Loop	Continuous improvement of the system.
J	Appendices	J-1 to J-10, from a policy example through the index methods (J-5, J-6) to a plan format.

Narrated film · 1:30

TMH 22 and its ten parts

A radial map puts TMH 22 at the centre with TMH 9, TMH 13, TMH 18, TMH 19, TRH 26 and GRAP 17 on the rim, then reveals Parts A to J one line at a time and closes on the idea that the register holds the data while policy stays with the authority.

Read the film transcript

What does TMH 22 decide, and what does it leave to other manuals? TMH 22 is the March 2013 draft South African Road Asset Management Manual, compiled under COTO, the Committee of Transport Officials. It is a template for a road authority's asset management system, not a survey method. For detail, it points to TMH 9 for visual ratings, TMH 13 for automated surveys, and TMH 19 for structures. TMH 18 sets out the file formats, TRH 26 the road classes, and GRAP 17 asset accounting. Part A covers organisation, Part B records the inventory, and Part C values it. Part D says which usage and condition data to collect and how often, and Part E turns them into indices. Parts F to H analyse the situation, determine the needs, and set out the asset management plans. The feedback loop asks for continuous improvement, and Part J holds the appendices, including the index methods. Four decisions stay outside TMH 22: survey methods, accounting policy, project design, and the level of asset management above its minimum. TMH 22 is a successor in practice to TRH 22, but it never says it replaces it. Its reference to TMH 20 points to TMH 18, so cite TMH 18 and name the version. The register holds the data, and the policy stays with the authority. Next, read TMH 9 for visual ratings and TMH 13 for the instrument surveys.

What does TMH 22 Part B put in a road asset register?

TMH 22 Part B sets out the inventory: a network definition, location referencing, an asset hierarchy from facility down to item, and the fixed asset register, which supports the figures in the annual financial statements (COTO, 2013). The network divides into roads, sections, links and assessment segments. A link is uniform in road type, cross-section, pavement construction, area and traffic; an assessment segment is the length that receives one rating, so the two need not match (COTO, 2013).

Part B uses functional classes 1 to 5 from TRH 26 (Version 1.0, August 2012), the South African road classification and access management manual, which adds Class 6 for walkways (COTO, 2012) (COTO, 2013).

Part C then values what Part B lists: current replacement cost is a unit rate multiplied by a quantity, and the depreciated form scales that by remaining against expected useful life (COTO, 2013). Some TMH 22 definitions are marked as taken from GRAP 17, the Standard of Generally Recognised Accounting Practice for property, plant and equipment (Accounting Standards Board, issued February 2010) (COTO, 2013) (ASB, 2010).

Synthetic example; every value is invented. Link 2 of Synthetic Road D9001 runs from official kilometre 3.200 to 7.450, a register length of 4.250 km. A centreline digitised in a geographic information system (GIS) measures 4.310 km, 60 m or 1.4 % longer. B.1.4 asks for both lengths; the length-dependent tolerance in B.1.3, not this guide, decides whether 60 m needs correcting (COTO, 2013). With a formation width of 9.0 m, the quantity is 4,250 m × 9.0 m = 38,250 m², using the register length as B.7.2 indicates; the GIS length would give 38,790 m², 540 m² more.

A synthetic 1.2 km segment length, not a TMH 9 value, would leave three whole segments and a 0.650 km remainder, so the register needs a remainder rule (see TMH 9 Part A, section A.3).

Where does TMH 22 Part D expect condition and usage data to come from?

Part D expects usage data from traffic counts, accident records and axle loads, and condition data from visual ratings and instrument measurements taken under other manuals (COTO, 2013). Part D says what to collect and how often, not how to rate a pavement or run a profiler.

• Visual condition. D.3.4 records each distress by type, degree and extent, with the rules left to TMH 9 for pavements and TMH 19 for structures (COTO, 2013).
• Instrument condition. D.4 covers roughness as the International Roughness Index (IRI), skid resistance, texture, deflection, imaging-based cracking and rutting, and sends survey planning to TMH 13. TMH 13 Part C defines roughness device classes and looks to TMH 22 for collection frequency (COTO, 2013) (COTO, 2016a).
• Exchange. D.5.2 says transfers use the COTO documented standard for road network data, which A.2 and D.4 call "TMH 20"; its content is TMH 18, the South African road asset data exchange manual (Draft Version 4, October 2014; Committee Draft 5.0, February 2016) (COTO, 2013) (COTO, 2014) (COTO, 2016i).

D.5 then covers collection frequency by road class (Tables D-4 and D-5), reporting intervals (D-7) and the lane, wheelpath and test interval of each instrument measurement (D-8). A note to Table D-8 says raw data are stored at the lowest interval supplied, and the table's wheelpath differs between measurements. Appendix J-4 gives an example routine that flags conflicting TMH 9 ratings (COTO, 2013).

Which indices do TMH 22 Part E and Appendices J-5 and J-6 define?

Part E defines engineering condition indices, functional indices and ways to bundle them. Appendix J-5 holds the deduct-point method and Appendix J-6 the visual condition index (VCI) method for flexible paved roads (COTO, 2013). A condition index is a percentage that falls as an asset deteriorates; a functional index appraises comfort, safety, congestion and operating cost (COTO, 2013). The deduct-point method allocates each defect a number of deduct points according to its relevance to the index being calculated (E.1.6) (COTO, 2013).

E.2 gives an index per component: surfacing (CISURF), flexible pavement structure (CIPAVE, also printed CIFPAVE), concrete (CICPAVE), block (CIBPAVE), formation (CIFORM) and unpaved roads (CIUNPAVED), and names the deduct-point method for all but the formation index (COTO, 2013).

The J-6 VCI is an arithmetic aggregation of TMH 9 ratings for flexible pavements, kept beside the component indices (COTO, 2013). Name the variant whenever a value is quoted; the guide on turning TMH 9 ratings into a visual condition index shows the steps. Tables E-1 to E-8 and the appendix tables hold the ranges, deduct points and weights, which this guide does not reprint. E.4.2 weights component indices by current replacement cost when bundling them (COTO, 2013).

How do TMH 22 Parts F to I turn indices into plans?

Part F ends with problem statements, Part G sorts the resulting needs into categories, estimates and ranks them, Part H turns them into plans, and Part I asks for continuous improvement (COTO, 2013). G.10 uses panel inspections to confirm network results, and says special maintenance and rehabilitation need further investigation such as material sampling and structural analysis (COTO, 2013).

The insight on network screening and project investigation works through that boundary, and the one on lifecycle cost scenarios shows why a G.5 life-cycle comparison should carry its assumptions.

What does TMH 22 leave to other manuals and to the authority?

Four decisions stay outside TMH 22. Rating and survey procedures go to TMH 9, TMH 13 and TMH 19, although D.4.3 names a roughness device class per road class. Accounting policies for valuation and depreciation (B.8) are the authority's. Project-level investigation and design are project work (D.3.1, G.9.1). Above its stated minimum, A.3.3 leaves the level of asset management to the authority (COTO, 2013).

TMH 22 points to these six documents, among others:

• TMH 9 supplies distress descriptions, degree and extent ratings and the visual segment length for all four pavement families, including the unpaved Part E that the guide on rating a gravel road under TMH 9 Part E covers (COTO, 2016b) (COTO, 2013).
• TMH 13 plans and controls automated surveys of roughness, rutting, skid resistance, texture, deflection and imaging (COTO, 2016d).
• TMH 18 sets out file formats for submitting network and condition data (COTO, 2014) (COTO, 2016i).
• TMH 19 covers visual assessment of bridges, culverts and other structures (COTO, 2020b).
• TRH 26 classifies roads by function (COTO, 2012).
• GRAP 17 sets out the accounting treatment of property, plant and equipment, which includes road networks (ASB, 2010).

The A.2 legislation is context here; this guide gives no legal or accounting advice. The register holds the data; policy stays with the authority.

What are the common misreadings of TMH 22?

Six points in TMH 22 invite misreading.

• TMH 22 is not TRH 22. Draft TRH 22 (1994) describes pavement management systems (CSRA, 1994). TMH 22 draws on past pavement management practice but never cites TRH 22 or says it supersedes it (COTO, 2013). Call it a successor in practice, not a declared replacement.
• "TMH 20" points to TMH 18. A.2 lists a "TMH 20" titled "Standard for Road Network Data" beside TMH 18 (COTO, 2013). RoadSense found no document numbered TMH 20 in the Department of Transport catalogue (Department of Transport, n.d.), and the running header of TMH 18 Draft Version 4 reads "COTO Standard for Road Network Data" (COTO, 2014). Cite TMH 18 with its version.
• CIPAVE and CIFPAVE are one index. The draft prints the flexible pavement structure index both ways, so write "CIPAVE (also printed CIFPAVE)" (COTO, 2013).
• The GRAP 17 date. A.2 prints "Issued March 2012". The Accounting Standards Board text is headed February 2010 and lists March 2012 as a later set of improvements, so take the date from it (ASB, 2010).
• Unit labels. D.4.5 says deflections are reported in micrometres, while the normalised deflection file (section 5.7) in TMH 18 Draft Version 4 and in Committee Draft 5.0 labels its columns nanometres. State the unit in every header (COTO, 2013) (COTO, 2014) (COTO, 2016i).
• Headers and levels. Running headers on Part H and Part I pages read "Part G", and Appendix J-3 is Level II in D.5.2 and the Part J list but Level III on its own pages (COTO, 2013).

What should a TMH 22 road asset register keep as evidence?

Keep these records so a reviewer can reproduce each entry:

• Edition and part letter of every manual used, with the TMH 18 version for exchanged files.
• Per link: road identifier, official start and end kilometre, surveyed length and sources.
• Component widths, quantities and the length rule.
• Raw interval data with units in the header, the lane and the wheelpath.
• The original ratings, the index variant and the verification result.

Last reviewed on 21 October 2026 against the editions cited.

Frequently asked

What is TMH 22?

TMH 22 (also written TMH22) is the Draft Road Asset Management Manual of March 2013, compiled under the Committee of Transport Officials (COTO) in the South African Technical Methods for Highways (TMH) series. It is a template for a road authority's asset management system covering the register, valuation, condition and usage data, indices, needs and plans, not a survey method.

What are the ten parts of TMH 22?

The March 2013 draft of TMH 22, the South African road asset management manual, has Parts A to J: General and Organisation; Inventory Data; Asset Valuation; Usage and Condition Data; Indices; Situational Analysis; Needs Determination; Asset Management Plans; Feedback Loop; and Appendices. Part J holds appendices J-1 to J-10, including the deduct-point system (J-5) and a visual condition index method (J-6).

What does TMH 22 Part B say a road asset register holds?

Part B of the Draft TMH 22 road asset management manual sets out the network definition (roads, sections, links and assessment segments), location referencing, an asset hierarchy from facility to item, natural attributes such as climate and topography, acquisition data, and the fixed asset register fields for road links, bridges and their components.

Does TMH 22 replace TRH 22?

TMH 22 itself does not state that it replaces TRH 22. Draft TRH 22 (1994) describes pavement management systems. Draft TMH 22 (March 2013) is a broader road asset management manual that draws on past pavement management practice, but it never cites TRH 22. TMH 22 is better described as a successor in practice to TRH 22 than as a declared replacement.

Does TMH 22 explain how to rate or measure road condition?

TMH 22 does not explain how to rate or measure road condition, and Draft TMH 22 says it does not provide detailed condition-assessment processes. Part D states which visual and instrument data to collect and how often, and sends the methods to TMH 9 for visual assessment of road pavements, TMH 13 for automated surveys and TMH 19 for road structures. The indices in Part E then turn those ratings and measurements into comparable numbers.

Where can I find the TMH 22 PDF, and which edition is it?

The Department of Transport road manuals catalogue links the TMH 22 draft as a PDF whose cover reads Draft TMH 22 Road Asset Management Manual, March 2013; the file name adds V8b. The catalogue lists no later edition. Cite the draft by its cover title and date, because TMH 22 is a draft and the file name is not an edition.

Where this connects

TMH 9 turns the register's segments into ratings, and TMH 13 sets out the instrument surveys that TMH 22 Part D expects. TMH 18 then packages both for the receiving authority.

References

1. COTO (2013). Draft TMH 22: Road Asset Management Manual. Draft, March 2013. Original source.Sections, tables and clauses are cited inline in each guide
2. Department of Transport (n.d.). Roads: Engineering Standard Guidelines and Manuals. Official catalogue; accessed 5 September 2026. Original source.TMH22 V8b Draft; TRH12; TRH15; TRH24 catalogue entries
3. COTO (2016b). TMH9: Manual for Visual Assessment of Road Pavements. Part A: General. Committee Draft Final, May 2016. Original source.Section A.2: degree and extent
4. COTO (2016d). TMH 13: Automated Road Condition Assessments. Part A: General. Committee Draft Final, May 2016. Original source.Sections, tables and clauses are cited inline in each guide
5. COTO (2016a). TMH13: Automated Road Condition Assessments. Part C: Roughness. Committee Draft Final, May 2016. Original source.Sections C.2–C.5; Table C.5 is for calibration-section selection
6. COTO (2014). TMH 18: Road Asset Data Electronic Exchange Formats. Draft Version 4, October 2014. Original source.Sections, tables and clauses are cited inline in each guide
7. COTO (2016i). TMH 18: Road Asset Data Electronic Exchange Formats. Committee Draft 5.0, February 2016. Original source.Sections, tables and clauses are cited inline in each guide
8. COTO (2020b). TMH19: Manual for the Visual Assessment of Road Structures. Part A: Road Structure Management Information. Draft Standard, August 2020. Original source.Sections, tables and clauses are cited inline in each guide
9. COTO (2012). TRH 26: South African Road Classification and Access Management Manual (RCAM). Version 1.0, August 2012. Original source.Sections, tables and clauses are cited inline in each guide
10. ASB (2010). GRAP 17: Property, Plant and Equipment (Standard of Generally Recognised Accounting Practice). Accounting Standards Board; cover dated February 2010; text version of 1 April 2026. Original source.Sections, tables and clauses are cited inline in each guide
11. CSRA (1994). Draft TRH22: Pavement Management Systems. Pretoria: Department of Transport, 1994. Original source.Technical Addendum A.3, equations A.3.1–A.3.3 and Table A.3.1, printed pp. 125–126; Section 6.2.2, printed pp. 55–56, for alternative-weight normalisation

Use the manual edition and project requirements that apply to your work. Worked examples use synthetic values and are not site-specific design advice.