# Putting road condition on a map

*A spreadsheet of segment scores is a correct answer to a question nobody in the
room is asking. The question is "which roads", and that is spatial.*

Most councils hold their road condition as rows: a segment identifier, a
chainage, a score, a date. It is the right structure for calculation and the
wrong one for a decision made by a group of people, because nobody in a council
chamber thinks in chainages. They think in *the road past the school* and *the
one the trucks use*.

Moving the same data onto a map changes three things, and none of them is
decoration.

## 1. The gaps become visible

On a spreadsheet, a missing condition score is a blank cell near the bottom of a
column of 900. On a map it is a grey line running through the north of the shire,
and the first question anyone asks is "why is that one grey?"

That is the single best argument for mapping. A network summary is only as honest
as its treatment of the roads nobody has looked at, and a table hides those
beautifully. A map cannot — provided the legend has a row for *not surveyed* that
is visibly different from both good and poor.

If the only way to show an unsurveyed road is to colour it as though it scored
zero, the map is worse than the spreadsheet.

The same applies to surface type. **61% of Australian local road length is
unsealed** — 413,000 km against 265,000 km sealed (ALGA, *2024 National State of
the Assets*). A map that colours gravel roads on a sealed-road scale is showing a
score that was never valid for them, across the majority of the network.

## 2. Patterns appear that no sort order would find

Deterioration is not randomly distributed. It follows drainage, soil, haulage
routes, the age of a subdivision, the year a contractor sealed a batch of
streets. Those patterns are spatial by nature, and a column sorted by score
cannot surface any of them — the roads that share a cause are scattered through
the list.

Seeing five poor segments that happen to sit along one creek line is the
beginning of a different conversation from seeing five poor segments ranked 14th
to 31st.

## 3. The conversation changes shape

A councillor shown a ranked list argues about the ranking. A councillor shown a
map argues about the roads — which is the argument you actually want, because it
is the one where evidence helps.

It also makes a particular objection answerable on the spot. *"Why isn't my
street on the list?"* is hard to answer from a table and easy to answer from a
map with the street's own score, its survey date and the treatment it would need
one click away.

## What makes a condition map usable rather than pretty

Four things, in rough order of how often they are got wrong:

**A legend that includes the unknown.** Good, fair, poor — and *not surveyed*, in
a colour that reads as absence rather than as a grade. Grey, usually. This is the
one that gets dropped.

**Colour that survives being printed in black and white**, because the map will
end up in a committee paper. Distinguishable by lightness, not only by hue.

**A date on the face of it.** Condition is a measurement with a shelf life. A map
with no as-at date invites a reader to assume it is current, and in two years it
will not be.

**Click-through to the evidence.** The map is a way in, not an answer. A segment
should open onto what was seen, when, by which method, and what the score was
built from. Without that the map is a picture, and a picture is not something
anyone can check.

## The thing a map cannot do

It cannot rank. A map shows you where the poor roads are; it does not tell you
which to do first, because that depends on cost, on what the treatment achieves,
on traffic, and on what else is competing for the same budget. Those are table
questions.

The useful arrangement is both, pointing at each other: the map for *which roads
and where*, the ranked programme for *in what order and at what cost*, and a way
to get from one to the other without re-querying anything.

## How PaveKeep handles this

PaveKeep puts the whole network on a map, coloured by condition, with a legend
that includes roads nobody has surveyed — and those report as unknown rather than
as zero, which is the point the rest of the product turns on. Open any segment
and it says what was seen, when, and by which method, with the arithmetic behind
the score.

The network also exports in a standard mapping format, so it opens in whatever
GIS the council already runs. Nothing is locked in.

PaveKeep is built for small and regional councils and is not yet in use at any
council.

## Sources

- Austroads (2025), *Guide to Pavement Technology Part 5: Pavement Evaluation and
  Treatment Design* — network-level condition survey practice, and the
  distinction between network-level screening and project-level analysis.
- Australian Local Government Association (2024), *National State of the Assets
  Report 2024* — the sealed and unsealed shares of local road length.
- LGAM, *Pavement Condition Assessment Manual*, based on the Bundaberg Regional
  Council Road Condition Assessment Manual — segment-level scoring, which is what
  a map renders.

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Source: https://pavekeep.com.au/knowledge/road-condition-on-a-map · PaveKeep · bound content