Real-world numbers gathered from OSM (Overpass), Esri aerial imagery, and
frame-sampled onboard video. Replaces estimation with measurement.
Key findings:
* Loop radii MEASURED via Kasa circle fit on OSM ways: 27.5-204 m,
mean 131 m (469 studs). Two cleanest fits (rms<1.5) are the true
helixes at 147 m (525 studs) and 124 m (441 studs).
* 6 of 8 curved ramps turn CLOCKWISE - matches the video captions
'right, right and you will reach the PA'.
* FIVE deck layers in the interchange (OSM layer 1-5). Current
PA_LIFT=56 models only one; faithful build wants 3+ overhead.
* Real PA footprint 181x174 m (parking) / 203x227 m (rest_area).
Current APRON 210x200 m already matches well - the divergence is
SHAPE (square vs rounded wedge), not extent.
* Scale clarified: PA work uses M=3.571 studs/m, NOT the 4.3 in
c1_georeference.json (different mapping, 366 m median error).
Video reference archived to NAS 004-video-reference/ (364 MB, 4 routes).
Hermes
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