# Independent Review Record
## Package: Road Low-Point Resilience — Corridor RD-SSC01-001
### Review reference: IND-REV-SSC01-01 | Review date: 2025-07-06

---

## 1. Source Inventory

The source directory contains seven files. Six are content documents corresponding to the six rows in the document register. The register itself (DOC-REG-SSC01-01) is present but lists only the six content documents by row; the register document is not self-referencing, which is normal practice. All six content documents carry document IDs, revisions, and statuses as tabulated below. No document in the register is marked pending, superseded, or missing.

| Document ID | Title | Rev | Status |
|---|---|---|---|
| RD-SSC01-001 | Road geometry and corridor profile | Rev B | Issued for review |
| DRN-SSC01-DES-01 | Low-point drainage design package | Rev C | Issued for review |
| ITS-SSC01-LAY-01 | Field equipment layout and levels | Rev A | Issued for review |
| PWR-SSC01-SCH-01 | Power, battery, and network schedule | Rev A | Issued for review |
| TOPS-SSC01-CASE-01 | Traffic operations case and VMS basis | Rev A | Issued for review |
| CRIT-SSC01-001 | Criteria memo and review comments | Rev A | Current |

---

## 2. Corridor Identity Ledger

| Item | Value | Primary source |
|---|---|---|
| Road segment | RD-SSC01-001, CH 0+000 to CH 2+400 | RD-SSC01-001 Rev B |
| Low point | LP-01 | RD-SSC01-001 Rev B |
| Low point chainage | CH 1+240 | RD-SSC01-001 Rev B |
| Datum | Metres AHD (all documents) | DOC-REG-SSC01-01; confirmed ITS-SSC01-LAY-01 |
| Cabinet | CAB-01 at CH 1+238, pad 43.775 m AHD | ITS-SSC01-LAY-01 Rev A |
| VMS | VMS-01 at CH 1+180 (approach side) | ITS-SSC01-LAY-01 Rev A |
| Storm case | STORM-01 (10-year burst) | DRN-SSC01-DES-01 Rev C; confirmed TOPS-SSC01-CASE-01 Rev A |
| Network case | ITS-NET-01 | PWR-SSC01-SCH-01 Rev A |
| Battery | BATT-01, 3.0 kWh, 290 W critical load | PWR-SSC01-SCH-01 Rev A |

All documents consistently reference LP-01, RD-SSC01-001, and AHD datum. The cabinet chainage (CH 1+238) is 2 m from the low-point chainage (CH 1+240), which is a physically plausible offset for a roadside installation and does not constitute a conflict. Design speed 70 km/h is stated in RD-SSC01-001 and confirmed in TOPS-SSC01-CASE-01. Storm case STORM-01 is used in both DRN-SSC01-DES-01 and TOPS-SSC01-CASE-01. No datum inconsistency is found.

---

## 3. Review Item Reasoning

### RLR-01 — Packet completeness
All six required documents (road geometry, drainage package, field equipment, power/comms, traffic operations, criteria memo) are present in the source directory, each with a document ID, revision letter, and status. The document register itself (DOC-REG-SSC01-01) is present. **Status: pass.**

### RLR-02 — Object identity
Checked for consistency of: chainage frame (CH 0+000–2+400), LP-01 designation and chainage (1+240), datum (AHD throughout), cabinet ID (CAB-01), storm case (STORM-01), design speed (70 km/h), and scenario (water over road at LP-01). No contradictions found across the six documents. **Status: pass.**

### RLR-03 — Drainage basis
All calculations are recomputed from packet source values using the assessment bases in CRIT-SSC01-001.

**Peak runoff** (Rational Method, Q = C·I·A/360):
  Q = 0.81 × 104.2 × 1.36 / 360 = **0.3189 m³/s** (package: 0.319 ✓, rounding difference ≤ 0.001)

**Gutter approach flow** (Q_runoff + bypass):
  = 0.3189 + 0.030 = **0.3489 m³/s** (package: 0.349 ✓)

**Gutter spread** (HEC-22 triangular inversion, T = [Q·n / (0.376·Sx^(5/3)·SL^(1/2))]^(3/8)):
  Sx = 0.027, SL = 0.010, n = 0.015
  T = **4.563 m** (package: 4.563 ✓). Allowable spread 5.50 m — passes.

**HGL at DRN-PIT-01** (Manning full-pipe + pit loss, working upstream from tailwater TW = 42.425 m AHD per TW-2025-02):
  Q_pipe = 0.3489 × 0.82 = 0.2861 m³/s (< inlet capture capacity 0.395 m³/s ✓)
  V = 0.2861 / (π×0.45²/4) = 1.799 m/s
  Sf = (1.799 × 0.0115 / 0.1125^(2/3))² = 0.007878
  hf = 0.007878 × 40.0 = 0.3151 m
  h_pit = 0.9 × 1.799² / (2×9.81) = 0.1484 m
  HGL = 42.425 + 0.3151 + 0.1484 = **42.889 m AHD** (package: 42.889 ✓)

**Controlling water level** (max of ponded pavement level and upstream HGL):
  Ponded level = LP-01 pavement + T × Sx = 43.490 + 4.563 × 0.027 = **43.613 m AHD**
  HGL = 42.889 m AHD
  Controlling WL = max(43.613, 42.889) = **43.613 m AHD** (package: 43.613 ✓)

All five drainage results reconcile with the package's own claimed values. **Status: pass.**

### RLR-04 — Equipment exposure (CAB-01 freeboard)
The package (ITS-SSC01-LAY-01 Rev A) claims a freeboard of 0.285 m and labels it "adequate."

The criterion (CRIT-SSC01-001) requires a minimum freeboard of **0.35 m above the controlling water level**. The controlling water level is 43.613 m AHD (established in RLR-03).

Correct freeboard = CAB-01 pad level − controlling water level
  = 43.775 − 43.613 = **0.162 m**

This fails the 0.35 m criterion by a deficit of **0.188 m**. The CAB-01 pad level required to satisfy the criterion is ≥ 43.963 m AHD.

Investigation of the package's own 0.285 m claim: back-calculation shows the package computed freeboard above the LP-01 pavement level (43.490 m AHD), not above the controlling water level (43.613 m AHD). This is an error of method — even the package's own freeboard of 0.285 m falls below the 0.35 m threshold. The "adequate" label is incorrect.

**Status: fail (critical).** Finding F-01 raised. The package cannot issue until CAB-01 pad level is raised or the controlling water level is reduced so that freeboard ≥ 0.35 m.

### RLR-05 — Traffic operation consequence (VMS legibility)
Legibility distance = 18 in × 40 ft/in = 720 ft = 219.456 m
Reading time at 70 km/h (19.444 m/s) = 219.456 / 19.444 = **11.29 s** (package: 11.29 ✓)
Available characters = 11.29 × 5.0 = 56.43 chars
MSG-01 length = 50 chars
Message margin = 56.43 − 50 = **6.43 chars > 0** — passes criterion.

Assessment speed (70 km/h) matches RD-SSC01-001 design speed. Storm case STORM-01 confirmed in TOPS-SSC01-CASE-01. **Status: pass.**

### RLR-06 — Power/comms resilience
**Battery runtime** (capacity × efficiency / critical load):
  = 3.0 kWh × 0.91 × 1000 Wh/kWh / 290 W = 2730 / 290 = **9.41 h ≥ 8 h** — passes.

**Network headroom**:
  Raw device demand = 3×7.5 + 1.0 + 0.25 + 0.15 = 23.90 Mbps
  With 17% protocol overhead: 23.90 × 1.17 = 27.963 Mbps
  With 28% future capacity buffer: 27.963 × 1.28 = 35.793 Mbps
  Headroom = 45.0 − 35.793 = **9.207 Mbps > 0** — passes.

**Status: pass.**

### RLR-07 — Comment and action closure
The criteria memo (CRIT-SSC01-001 Rev A) records three review comments:
- C-01 (Drainage, minor): Confirm inlet blockage allowance. Status: **Closed**.
- C-02 (Electrical, minor): Confirm BATT-01 sizing basis. Status: **Closed**.
- C-03 (Traffic, minor): Confirm MSG-01 legibility basis. Status: **Closed**.

No comment is open or carried. However, the critical failure identified at RLR-04 (cabinet freeboard error) is a finding raised by this independent review and was not captured as a prior comment. It is registered as F-01 in the findings section and carried as action A-01 in the action register. **Status: pass** on original comment closure; the new finding does not affect comment-closure status but does affect readiness.

### RLR-08 — Readiness consistency
RLR-04 carries a critical failure (F-01). Under the review rules, an unresolved critical failure means the package is not ready to issue. The readiness decision is **not_ready_to_issue**, which is consistent with the matrix. **Status: pass.**

### RLR-09 — Claim boundary
This review is performed against a task-owned synthetic source packet. No authority approval, accepted project evidence, full standards compliance, source-pack hardening, executable-verifier readiness, or benchmark readiness is claimed. See claim boundary statement in the JSON block. **Status: pass.**

---

## 4. Findings

### F-01 (Critical) — CAB-01 freeboard below criterion

| Field | Detail |
|---|---|
| Item | RLR-04 |
| Severity | Critical |
| Source | ITS-SSC01-LAY-01 Rev A |
| Object | CAB-01 |
| Consequence | CAB-01 pad level (43.775 m AHD) provides only 0.162 m freeboard above the controlling water level (43.613 m AHD), against a required minimum of 0.350 m. Deficit is 0.188 m. The package's label "adequate" is incorrect and appears to arise from measuring freeboard above the LP-01 pavement level (43.490 m AHD) rather than the controlling water level. Under the STORM-01 design event, the cabinet is at risk of flood inundation with an 0.188 m shortfall. |
| Action | A-01: Revise ITS-SSC01-LAY-01 to raise CAB-01 pad level to ≥ 43.963 m AHD (or demonstrate a reduction in controlling water level that achieves freeboard ≥ 0.35 m). Correct the freeboard computation to reference the controlling water level, not the pavement level. Reissue ITS-SSC01-LAY-01 at next revision for review. |

---

## 5. Action Register

| ID | Action | Owner | Linked item |
|---|---|---|---|
| A-01 | Raise CAB-01 pad level to ≥ 43.963 m AHD (or reduce controlling WL accordingly); correct freeboard computation base to reference controlling water level; reissue ITS-SSC01-LAY-01 | Design team (ITS discipline) | RLR-04 |

---

## 6. Readiness Decision

**NOT READY TO ISSUE.**

One critical failure is outstanding (F-01, RLR-04). The cabinet freeboard shortfall is 0.188 m and is not a documentation gap — the pad level is geometrically insufficient. The package must be revised before it can be issued.

---

```json
{
  "source_inventory": [
    {"doc_id": "RD-SSC01-001",       "revision": "Rev B", "status": "Issued for review"},
    {"doc_id": "DRN-SSC01-DES-01",   "revision": "Rev C", "status": "Issued for review"},
    {"doc_id": "ITS-SSC01-LAY-01",   "revision": "Rev A", "status": "Issued for review"},
    {"doc_id": "PWR-SSC01-SCH-01",   "revision": "Rev A", "status": "Issued for review"},
    {"doc_id": "TOPS-SSC01-CASE-01", "revision": "Rev A", "status": "Issued for review"},
    {"doc_id": "CRIT-SSC01-001",     "revision": "Rev A", "status": "Current"}
  ],
  "identity_ledger": {
    "road_segment":      "RD-SSC01-001, CH 0+000 to CH 2+400",
    "low_point":         "LP-01",
    "low_point_chainage":"CH 1+240",
    "datum":             "Metres AHD (all documents consistent)",
    "cabinet":           "CAB-01 at CH 1+238, pad 43.775 m AHD",
    "vms":               "VMS-01 at CH 1+180 (approach side), 18 in character height",
    "storm_case":        "STORM-01 (10-year burst)",
    "network_case":      "ITS-NET-01",
    "battery":           "BATT-01, 3.0 kWh, 0.91 usable efficiency, 290 W critical load"
  },
  "review_matrix": {
    "RLR-01": {
      "status": "pass",
      "evidence": "All six content documents present with IDs, revisions, and statuses as listed in DOC-REG-SSC01-01. Document register itself is present. No document is missing or lacking a revision."
    },
    "RLR-02": {
      "status": "pass",
      "evidence": "LP-01 at CH 1+240 consistent across RD, DRN, ITS, TOPS. Datum AHD confirmed in all documents. Design speed 70 km/h in RD-SSC01-001 and TOPS-SSC01-CASE-01. Storm case STORM-01 in DRN and TOPS. CAB-01 at CH 1+238 (2 m from LP-01, physically consistent). No contradictions found."
    },
    "RLR-03": {
      "status": "pass",
      "evidence": "Recomputed Q=0.3189 m3/s (pkg 0.319), Q_gutter=0.3489 m3/s (pkg 0.349), T=4.563 m (pkg 4.563), HGL=42.889 m AHD (pkg 42.889), controlling WL=43.613 m AHD (pkg 43.613). All reconcile within rounding. Tailwater TW-2025-02 (42.425 m AHD) stated and used. Spread 4.563 m < allowable 5.50 m."
    },
    "RLR-04": {
      "status": "fail",
      "evidence": "CAB-01 pad 43.775 m AHD minus controlling WL 43.613 m AHD = 0.162 m freeboard. Required 0.350 m. Deficit 0.188 m. Package incorrectly claims 0.285 m freeboard (computed against pavement level 43.490 m AHD rather than controlling WL). Even the package's own value 0.285 m < 0.350 m. Finding F-01 raised."
    },
    "RLR-05": {
      "status": "pass",
      "evidence": "Legibility distance 720 ft = 219.456 m at 70 km/h yields reading time 11.29 s. Available chars = 11.29 × 5.0 = 56.43. MSG-01 = 50 chars. Margin = 6.43 chars > 0. Assessment speed matches RD-SSC01-001. Storm case STORM-01 confirmed in TOPS-SSC01-CASE-01."
    },
    "RLR-06": {
      "status": "pass",
      "evidence": "Battery runtime = 3.0 kWh × 0.91 × 1000 / 290 W = 9.41 h >= 8 h required. Network demand = (3×7.5 + 1.0 + 0.25 + 0.15) × 1.17 × 1.28 = 35.793 Mbps. Headroom = 45.0 - 35.793 = 9.207 Mbps > 0."
    },
    "RLR-07": {
      "status": "pass",
      "evidence": "All three prior review comments (C-01, C-02, C-03) are marked Closed in CRIT-SSC01-001. No open, pending, or unowned comments. New finding F-01 from this review is registered as action A-01 in the action register."
    },
    "RLR-08": {
      "status": "pass",
      "evidence": "RLR-04 is a critical fail. Readiness decision is not_ready_to_issue, which is consistent with the matrix (critical unresolved failure present). No contradiction between findings, matrix, and decision."
    },
    "RLR-09": {
      "status": "pass",
      "evidence": "Review explicitly limited to the task-owned synthetic source packet. No authority approval, accepted project evidence, full standards compliance, source-pack hardening, executable-verifier readiness, or benchmark readiness is claimed. See claim_boundary_statement."
    }
  },
  "computed_evidence": {
    "peak_runoff_m3_s":            0.3189,
    "gutter_approach_flow_m3_s":   0.3489,
    "spread_width_m":              4.5628,
    "allowable_spread_m":          5.50,
    "controlling_water_level_m":   43.6132,
    "cabinet_freeboard_m":         0.1618,
    "vms_message_margin_chars":    6.4315,
    "battery_runtime_h":           9.4138,
    "network_headroom_mbps":       9.2074
  },
  "findings": [
    {
      "item":        "RLR-04",
      "severity":    "critical",
      "source_id":   "ITS-SSC01-LAY-01",
      "object_id":   "CAB-01",
      "consequence": "CAB-01 pad level 43.775 m AHD provides 0.162 m freeboard above the controlling water level 43.613 m AHD; criterion requires 0.350 m. Deficit is 0.188 m. The package's own freeboard claim of 0.285 m is also below criterion and is itself erroneous because it was measured from the LP-01 pavement level (43.490 m AHD) rather than the controlling water level. Under the STORM-01 design event the cabinet is at risk of flood inundation.",
      "action":      "Raise CAB-01 pad level to >= 43.963 m AHD (i.e. controlling WL 43.613 + required freeboard 0.350). Correct the freeboard computation in ITS-SSC01-LAY-01 to reference the controlling water level. Reissue ITS-SSC01-LAY-01 at next revision for review. If a redesign reduces the controlling water level, demonstrate the new level and recheck freeboard before reissue."
    }
  ],
  "information_requests": [],
  "action_register": [
    {
      "action":      "Raise CAB-01 pad level to >= 43.963 m AHD; correct freeboard computation base to controlling water level (43.613 m AHD); reissue ITS-SSC01-LAY-01 for review",
      "owner":       "Design team — ITS discipline",
      "linked_item": "RLR-04"
    }
  ],
  "readiness_decision": "not_ready_to_issue",
  "claim_boundary_statement": "This review record covers a task-owned synthetic source packet assembled for assessment purposes and does not constitute authority approval, accepted project evidence, certification of full standards compliance, source-pack hardening, executable-verifier readiness, or benchmark readiness. All numeric conclusions are derived solely from values contained in the source packet as described. No external standards, datasheets, or design guides have been imported."
}
```