System

New Tyne Crossing Transport Appraisal System, full QC review triggered by first-pass-complete status. The project contains 148 requirements across 6 documents, 137 trace links, 100 Substrate facts in namespace SE:new-tyne-crossing-appraisal, and 9 diagrams (post-cleanup). Seven subsystems: {{entity:Transport Demand Modelling}}, {{entity:Traffic Microsimulation}}, {{entity:Economic Appraisal Engine}}, {{entity:Environmental Assessment}}, {{entity:Geospatial Analysis Platform}}, {{entity:Data Acquisition and Management}}, and {{entity:Appraisal Reporting}}.

Findings

Rationale gaps: 21 of 148 requirements lacked rationale — all from the final {{entity:Appraisal Reporting}} subsystem decomposition session (session 273). Affected refs: {{sub:SUB-REQS-042}} through {{sub:SUB-REQS-049}}, {{ifc:IFC-DEFS-024}} through {{ifc:IFC-DEFS-029}}, VER-METHODS-031 through VER-METHODS-036, and ARC-DECISIONS-010. One requirement (ARC-DECISIONS-010) also lacked a verification method.

Duplicate diagrams: Six duplicate diagrams found across four subsystems. Transport Demand Modelling had 2 copies, Environmental Assessment had an original plus “v2”, Data Acquisition and Management had 4 copies (3 duplicates), and Appraisal Reporting had 2 copies.

Verification coverage: Prior to corrections, only 36 of 78 SUB+IFC requirements (46%) had verifies trace links. All 29 IFC requirements were covered, but only 7 of 49 SUB requirements had corresponding VER entries.

Ambiguity: Two requirements flagged for ambiguous language — ARC-DECISIONS-010 (“appropriate”) and VER-METHODS-030 (“appropriate” context acceptable for a verification pass criterion description). The lint finding about {{hex:40A479D9}} lacking Physical Object trait remains acknowledged — the system is correctly classified as abstract software.

No degraded-mode requirements were found, which is correct for a transport appraisal system (it is an analytical tool, not a real-time operational system).

flowchart TB
  n0["Transport Demand Modelling"]
  n1["Traffic Microsimulation"]
  n2["Economic Appraisal Engine"]
  n3["Environmental Assessment"]
  n4["Geospatial Analysis Platform"]
  n5["Data Acquisition and Management"]
  n6["Appraisal Reporting"]
  n5 -->|Traffic counts, OD matrices| n0
  n0 -->|Turning count matrices| n1
  n0 -->|Time savings matrices| n2
  n1 -->|Journey time reliability| n2
  n0 -->|Traffic flows and speeds| n3
  n4 -->|Receptor locations| n3
  n2 -->|BCR, NPV, benefits| n6
  n3 -->|Impact scores| n6
  n4 -->|Route plans, maps| n6

Corrections

Rationale added to all 21 requirements. Each rationale ties the requirement to its regulatory or engineering driver: TAG/WebTAG unit references for economic appraisal requirements, EIA Regulations 2017 for environmental reporting, Treasury Green Book for audit trail, DMRB GG 142 for option sifting, and Equality Act 2010/WCAG 2.1 for accessibility. Verification method (Inspection) added to ARC-DECISIONS-010.

Six duplicate diagrams deleted: diagram-1773775197287 (Transport Demand Modelling), diagram-1773777930297 (Environmental Assessment v2), diagram-1773779214360, diagram-1773779285874, diagram-1773779291761 (three Data Acquisition duplicates), and diagram-1773785140950 (Appraisal Reporting). Oldest diagram retained in each case.

Three new verification entries created: {{sub:VER-037}} (network coding accuracy inspection for {{sub:SUB-REQS-001}}), {{sub:VER-038}} (signal controller emulation test for {{sub:SUB-REQS-002}}), and {{sub:VER-039}} (results extraction demonstration for {{sub:SUB-REQS-005}}). Trace links created for all three. VER coverage now 39/78 (50%).

Baseline QC-2026-03-17 created at 148 requirements, 137 trace links.

Residual

SUB VER coverage remains at 10/49 (20%) — only the most critical microsimulation requirements have verification entries. Remaining 39 SUB requirements need VER entries in a future session. The lint finding about physical constraints on an abstract system ({{stk:STK-NEEDS-002}}, {{stk:STK-NEEDS-008}}, {{sys:SYS-REQS-011}}) is a known false positive — the system has hosting requirements but is not itself a physical object.

Next

System is now qc-reviewed and ready for validation (Flow D). The validation session should assess whether 7 subsystems adequately cover a UK transport appraisal, check if any subsystems need further decomposition (Economic Appraisal Engine has 8 components, which may warrant sub-decomposition), and evaluate whether the 49 SUB requirements distribute realistically across subsystems. Remaining SUB VER entries should be created during or after validation.