Historical system archive / snapshot v3
A year watching Bay Bridge traffic
Algorithmic crossing detections from a window-facing camera, collected continuously from August 2025 through July 2026. The live system is now offline; this archive preserves the measurements, operating history, and limitations.
Collection complete
Derived snapshot verified
Lossless TSDB archive pending
Night sensor regime changed Mar 2026
No source data deleted
Daily traffic estimate
Mean flow by weekday
Directional signature
These are outputs from a motion-tracking algorithm, not official bridge counts.
No labeled validation set exists, so false-positive and false-negative rates
are unknown. Public Caltrans data is nearly directionally balanced while this
camera reports roughly 65% SF-bound / 35% Oakland-bound, demonstrating strong
direction-dependent measurement bias. See External
Validation. Relative speed is recorded in pixels per second and is not
converted to mph.
The Bay Lights commissioning and March 20, 2026 public relighting created a
major nighttime measurement discontinuity. Animated LEDs are detected as
motion, producing substantially noisier nighttime counts after relighting.
Use the period controls in Explorer, Typical Week, and Notable Days rather than
mixing the regimes for night-sensitive comparisons.
What to inspect next
Historical explorer →
Filter the complete hourly series by date and direction.
Typical week →
September-style weekday profiles with percentile envelopes.
Notable days →
Rank complete days and inspect directional imbalance.
External validation →
Official counts, directional bias, and interpretation limits.
SOURCE: Prometheus query-range snapshot · STEP: 300 s · TIMEZONE: America/Los_Angeles · SNAPSHOT: archive-v3