Methodology · Goldnet Group

DCOA Crash Analysis

How we classify, risk-rate, and report road-safety crashes — using four public-authority frameworks, defensibly, without invented numbers.

What we do

DCOA (Dashcam Owners Australia) turns curator-vetted dashcam crash records into structured, citable road-safety briefs. Every crash gets a standard classification, a risk-star indication, and a treatment recommendation grounded in published Australian road-safety guidance — not in opinion.

The Four Frameworks

Our methodology stands on four public, citable frameworks. We never substitute proprietary judgement for these.

VicRoads DCA Chart

Authoritative crash-type classification — 9 top-level categories (H, NS, O, RE, P, A, HO, RO, U) with sub-codes underneath.

VicRoads Safe System Assessment

Applies Safe System principles (safe roads, speeds, vehicles, road users) to each location.

AusRAP Star Rating Protocol

Infrastructure-based risk score on a 1–5 scale (1 = highest risk, 5 = lowest).

Austroads/ATAP CRF values

Crash Reduction Factors from Austroads compendia — used to rank treatment cost-effectiveness.

Source: canon:fact-dcoa-analytical-methodology-foundation-2026-05-18

Map — 100 real rear-end crashes

Sample of 100 real Victorian rear-end crashes (DCA 130 — REAR END, VEHICLES IN SAME LANE) drawn from the VicCrashRisk database. Markers are coloured by injury severity. Click any marker for the de-identified record.

100
RE crashes plotted
35,683
Total DCA-130 in DB
19
Serious injury
81
Other injury
Serious injury (SEV 2) Other injury (SEV 3)

Source: canon:fact-vicrisk-data-source-locked-2026-05-13 · DCA code per canon:fact-dca-chart-victoria-2026-05-18. Sample drawn from /var/www/sites/vicrisk/data.db, accident table, DCA_CODE='130'. ACCIDENT_NO is the official de-identified VicRoads key. Tiles © OpenStreetMap contributors.

1 · Classification — VicRoads DCA Chart

Each crash is mapped to one of the 9 top-level VicRoads DCA categories below. Sub-DCA codes refine within each top-level group.

9 DCA crash-type categories

Categorical reference — not crash frequency. Frequency depends on the dataset under analysis.

Source: canon:fact-dca-chart-victoria-2026-05-18 (HTTP 200 verified, VicRoads portal).

2 · Risk rating — AusRAP Star Scale

AusRAP infrastructure star ratings run 1 → 5. 1★ is the highest-risk environment, 5★ the safest. Exact numeric thresholds are not held in our canon and are not reproduced here.

AusRAP 1–5 star risk scale (conceptual)

Conceptual scale only — numeric thresholds intentionally omitted (not in canon).

Source: canon:fact-ausrap-star-rating-protocol-2026-05-18

3 · Treatment effectiveness — Austroads CRF values

Crash Reduction Factors below are drawn verbatim from the Austroads compendia (AP-R560-18 and AP-R515-16). Ranges are shown as midpoints with the canonical range in the tooltip.

CRF (% casualty-crash reduction) by treatment

Values exact per canon table; ranges shown as midpoints. Source PDFs staged at /opt/gaios/fleet/shared/data/austroads/.

Source: canon:data-austroads-crf-table-2026-05-19 (AP-R560-18, AP-R515-16).

4 · The 7 mandatory output fields

Every DCOA brief delivers these seven fields, in this order, per our SSS snippet specification.

  1. Road name + suburbLocation
  2. Crash countNumber of crashes in analysis period
  3. Crash history periode.g. "2019–2023"
  4. Risk star rating1–5 star AusRAP-equivalent
  5. Primary crash typePer VicRoads DCA Chart
  6. Key treatment recommendationTop-ranked treatment
  7. Estimated investmentCost estimate (indicative)

Source: canon:fact-sss-snippet-format-benchmark-2026-05-18

Worked example

"Vehicle rear-ended a stopped car at a signalised T-intersection, wet road, dusk."

DCA code RE — Rear-end per the VicRoads DCA Chart (one of the 9 top-level categories; sub-DCA 130 — REAR END, VEHICLES IN SAME LANE).

Risk indication 2★ candidate — qualitative only. Reasoning: signalised T-intersection adds rear-end and right-turn conflict points; wet surface reduces tyre friction; dusk reduces driver perception-reaction time. Numeric AusRAP thresholds are not held in canon, so this rating is illustrative — a full AusRAP coding run would be required to confirm.

Sources: canon:fact-dca-chart-victoria-2026-05-18 · canon:fact-ausrap-star-rating-protocol-2026-05-18

What we have not measured

Honest gaps

  • Exact AusRAP Australian numeric star-rating thresholds.
  • Sub-DCA code refinement for individual map markers (top-level 130 confirmed; finer sub-codes require the DCA Chart decision tree).
  • Cost estimate for the recommended treatment — canon notes snippets are "indicative only, not costed".
  • Location-specific star rating — example shown is illustrative; needs a full AusRAP coding run.

Source: canon:fact-dcoa-output-layer-built-vic3-2026-05-24