Pipeline

Traffic Overlay ETL

Coverage: Coverage window unavailable for this page.

Built 2026-03-03 02:23 UTC · Commit defd5c8

Page Navigation

Data Provenance

flowchart LR
  04_traffic_overlay(["Traffic Overlay ETL"])
  f1_04_traffic_overlay[/"data/penndot-traffic/aadt_raw.json"/] --> 04_traffic_overlay
  f2_04_traffic_overlay[/"data/GTFS/shapes.txt"/] --> 04_traffic_overlay
  f3_04_traffic_overlay[/"data/GTFS/trips.txt"/] --> 04_traffic_overlay
  a1_04_traffic_overlay{"PennDOT ArcGIS Roadway Traffic Layer"} --> 04_traffic_overlay
  04_traffic_overlay --> tp_route_traffic[("route_traffic")]
  classDef page fill:#dbeafe,stroke:#1d4ed8,color:#1e3a8a,stroke-width:2px;
  classDef table fill:#ecfeff,stroke:#0e7490,color:#164e63;
  classDef dep fill:#fff7ed,stroke:#c2410c,color:#7c2d12,stroke-dasharray: 4 2;
  classDef file fill:#eef2ff,stroke:#6366f1,color:#3730a3;
  classDef api fill:#f0fdf4,stroke:#16a34a,color:#14532d;
  classDef pipeline fill:#f5f3ff,stroke:#7c3aed,color:#4c1d95;
  class 04_traffic_overlay page;
  class tp_route_traffic table;
  class f1_04_traffic_overlay,f2_04_traffic_overlay,f3_04_traffic_overlay file;
  class a1_04_traffic_overlay api;

Findings

Findings: Traffic Overlay ETL

Summary

Route-level traffic exposure metrics are computed from PennDOT AADT segments and written to prt.db.

Notes

Matching diagnostics include segment counts and route match rates.
Cached PennDOT responses are reused when available.

Methods

Methods: Traffic Overlay ETL

Question

How do we estimate roadway traffic exposure for each transit route?

Approach

Fetch or read cached PennDOT roadway traffic segments for Allegheny County.
Load GTFS route geometry and densify segment points.
Perform KDTree spatial matching between route points and roadway segments.
Aggregate matched segment AADT/truck metrics by route.
Rebuild route_traffic in prt.db.

Data

PennDOT ArcGIS roadway traffic layer (AADT/truck share)
GTFS shapes.txt and trips.txt
Cached PennDOT JSON under data/penndot-traffic/

Output

route_traffic table in data/prt.db

Tables Produced

Table	Description
`route_traffic`	Route-level traffic exposure metrics including weighted AADT and match quality.

Sources

Name	Type	Why It Matters	Owner	Freshness	Caveat
data/penndot-traffic/aadt_raw.json	file	Cached PennDOT ArcGIS feature response for Allegheny County roadway segments.	Local project data owner not specified.	Snapshot file; refresh by rerunning its pipeline step.	May lag upstream source updates.
data/GTFS/shapes.txt	file	GTFS route shape geometry points.	Local project data owner not specified.	Snapshot file; refresh by rerunning its pipeline step.	May lag upstream source updates.
data/GTFS/trips.txt	file	GTFS shape-to-route mapping.	Local project data owner not specified.	Snapshot file; refresh by rerunning its pipeline step.	May lag upstream source updates.
PennDOT ArcGIS Roadway Traffic Layer	api	Public roadway segment AADT and truck percentage attributes.	Hosted by gis.penndot.gov.	Queried during pipeline execution; freshness depends on upstream updates.	Availability and schema can change without notice.