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    "story_id": "mp-2026-08-18-014",
    "source_story_id": "tmp-story-calibration-free-vehicle-speed",
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    "headline": "Thirty-Six Vehicle Points Replaced the Roadside Ruler",
    "slug": "thirty-six-vehicle-points-replaced-the-roadside-ruler",
    "dek": "A per-frame keypoint template estimates monocular vehicle speed without fixed camera calibration or roadway reference marks.",
    "summary": "A per-frame keypoint template estimates monocular vehicle speed without fixed camera calibration or roadway reference marks.",
    "body_text": "The method detects 36 vehicle keypoints, updates a homography each frame and compares keypoint-only tracking with warped optical flow. Across more than 400 roadside and overhead clips spanning 30 to 100 miles per hour, warped flow produced mean absolute errors of 15.0 and 9.7 percent on two datasets; trimming edge-of-frame outliers improved those to 11.7 and 7.6 percent. The remaining errors are material for enforcement, so the result supports low-cost estimation research rather than automatic evidentiary reliability.",
    "why_it_matters": "A per-frame keypoint template estimates monocular vehicle speed without fixed camera calibration or roadway reference marks.",
    "limitations": [
      "The method detects 36 vehicle keypoints, updates a homography each frame and compares keypoint-only tracking with warped optical flow."
    ],
    "importance": 8,
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    "first_published_at": "2026-08-18T09:00:00.000-04:00",
    "modified_at": "2026-08-18T09:00:00.000-04:00",
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        "qualification": "The method detects 36 vehicle keypoints, updates a homography each frame and compares keypoint-only tracking with warped optical flow."
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    "source_ids": [
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    "tags": [
      "computer vision",
      "vehicle speed",
      "homography",
      "traffic safety"
    ],
    "image_url": null,
    "corrections": []
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  "sources": [
    {
      "source_id": "source-2026-08-18-014",
      "title": "arXiv preprint 2608.16785",
      "publisher": "arXiv",
      "url": "https://arxiv.org/abs/2608.16785",
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      "source_type": "primary_research",
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      "published_at": "2026-08-16T20:00:00.000-04:00",
      "accessed_at": "2026-08-18T08:25:00.000-04:00",
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    "name": "The Machine Press",
    "url": "https://themachinepress.com",
    "description": "A daily newspaper for the age of artificial intelligence."
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  "cite_this_report": {
    "title": "Thirty-Six Vehicle Points Replaced the Roadside Ruler",
    "publisher": "The Machine Press",
    "published_at": "2026-08-18T09:00:00.000-04:00",
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