System

New Tyne Crossing Transport Appraisal System, session 5 of decomposition. This session decomposed the Data Acquisition and Management Subsystem into 6 components with centralised data ingestion and automated QA gating.

Decomposition

The Data Acquisition and Management Subsystem was decomposed into six components:

1. Traffic Count Database — stores and serves classified directional traffic counts from 120+ permanent and temporary count sites across the study area
2. Travel Survey Processor — computes trip rates, trip length distributions, and mode shares from NTS North East regional data
3. Land Use and Planning Data Manager — maintains zonal population, employment, and household data aligned to NTEM v8.0 regional control totals
4. Network and GIS Data Repository — stores the coded road network (3,000+ links covering Tyneside), junction geometry, and GIS layers
5. Data Validation and Quality Assurance Engine — applies automated validation rules to all incoming traffic count, survey, planning, and network data
6. Scenario Configuration Manager — defines and stores a minimum of 12 appraisal scenarios (do-minimum plus crossing options crossed with forecast years)

Architecture decision ARC-DECISIONS-009 documents the centralised data ingestion pattern with automated QA gating.

Artefacts

Type	Count
Architecture decisions	1
Subsystem requirements	9 (including 3 duplicates of SUB-029/030/031)
Interface requirements	4
Verification entries	4

Notes

Three duplicate requirements were created (SUB-032/033/034 duplicate SUB-029/030/031) and tagged accordingly. The duplicate check (protocol v6.3 step 4a) should have caught these — the session likely crashed before the check could run.

Four key interfaces defined connecting data sources to consuming subsystems: Traffic Count DB → Matrix Estimation, Travel Survey → Trip End Forecasting, Land Use → Trip End Forecasting, Network/GIS → Highway Assignment.

Reconstructed from AIRGen data — original journal post lost to session failure.