{
  "catalog_id": 8,
  "title": "Low-speed two-car collision with resident onlookers",
  "source_template": "police",
  "summary": "Counterfactual low-speed rear-end contact occurs at time zero. Two cars settle in the ego corridor while six residents approach from both sidewalks and gather around them. The obstruction remains through 40 seconds.",
  "focus_xy": [
    36.5,
    0.5
  ],
  "initial_review_time_s": 0,
  "ego_stop_x_m": 12,
  "ego_release_s": -1,
  "events": [
    {
      "time_s": -7,
      "label": "Rear car approaches a stopped lead car; six residents remain on the sidewalks."
    },
    {
      "time_s": 0,
      "label": "Rear car makes low-speed bumper contact with the lead car without mesh penetration."
    },
    {
      "time_s": 1.5,
      "label": "Both cars finish a short shared forward roll and remain stopped."
    },
    {
      "time_s": 2,
      "label": "Residents begin approaching after both cars have stopped."
    },
    {
      "time_s": 8,
      "label": "Residents gather behind, beside and ahead of the stopped cars."
    },
    {
      "time_s": 11,
      "label": "All six residents have reached separated viewing positions around the collision."
    },
    {
      "time_s": 24,
      "label": "Residents continue watching; neither car is moved."
    },
    {
      "time_s": 40,
      "label": "Two cars and six onlookers remain present; the ego corridor is still obstructed."
    }
  ],
  "actors": [
    {
      "id": "c008_car_a",
      "label": "Collision lead car",
      "kind": "car",
      "role": "Stopped car contacted from behind",
      "color": "silver",
      "length_m": 4.4,
      "width_m": 1.8,
      "height_m": 1.48,
      "keys": [
        {
          "t": -7,
          "x": 38.5,
          "y": 0,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        },
        {
          "t": -3,
          "x": 38.5,
          "y": 0,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        },
        {
          "t": -1,
          "x": 38.5,
          "y": 0,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        },
        {
          "t": 0,
          "x": 38.5,
          "y": 0,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        },
        {
          "t": 1,
          "x": 38.7,
          "y": 0,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        },
        {
          "t": 1.5,
          "x": 38.75,
          "y": 0,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        },
        {
          "t": 40,
          "x": 38.75,
          "y": 0,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        }
      ],
      "attach_to": "",
      "attach_start_s": -7,
      "attach_end_s": 40,
      "attach_offset_xyz": [
        0,
        0,
        0
      ],
      "interaction": "Rear bumper is at x=36.3 at contact. Rolls forward 0.25 metres with c008_car_b, maintaining tangent bumper contact, then remains stationary."
    },
    {
      "id": "c008_car_b",
      "label": "Collision rear car",
      "kind": "car",
      "role": "Slowly approaching car making rear-end contact at time zero",
      "color": "red",
      "length_m": 4.4,
      "width_m": 1.8,
      "height_m": 1.48,
      "keys": [
        {
          "t": -7,
          "x": 27.3,
          "y": 0,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        },
        {
          "t": -3,
          "x": 32.3,
          "y": 0,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        },
        {
          "t": -1,
          "x": 33.7,
          "y": 0,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        },
        {
          "t": 0,
          "x": 34.1,
          "y": 0,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        },
        {
          "t": 1,
          "x": 34.3,
          "y": 0,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        },
        {
          "t": 1.5,
          "x": 34.35,
          "y": 0,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        },
        {
          "t": 40,
          "x": 34.35,
          "y": 0,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        }
      ],
      "attach_to": "",
      "attach_start_s": -7,
      "attach_end_s": 40,
      "attach_offset_xyz": [
        0,
        0,
        0
      ],
      "interaction": "Front bumper first meets c008_car_a at x=36.3 and t=0, at approximately 0.4 m/s. No prior overlap, rebound or subsequent repositioning occurs."
    },
    {
      "id": "c008_r1",
      "label": "Resident watching from behind",
      "kind": "human",
      "role": "South-side resident approaching the rear of the collision",
      "color": "brown",
      "length_m": 0.45,
      "width_m": 0.5,
      "height_m": 1.75,
      "keys": [
        {
          "t": -7,
          "x": 30,
          "y": -5.1,
          "z": 0,
          "heading_deg": 90,
          "pose": "stand"
        },
        {
          "t": 2,
          "x": 30,
          "y": -5.1,
          "z": 0,
          "heading_deg": 90,
          "pose": "walk"
        },
        {
          "t": 6,
          "x": 30,
          "y": -1.5,
          "z": 0,
          "heading_deg": 90,
          "pose": "walk"
        },
        {
          "t": 8,
          "x": 30,
          "y": 0.3,
          "z": 0,
          "heading_deg": 90,
          "pose": "stand"
        },
        {
          "t": 9,
          "x": 30,
          "y": 0.3,
          "z": 0,
          "heading_deg": 0,
          "pose": "point"
        },
        {
          "t": 24,
          "x": 30,
          "y": 0.3,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        },
        {
          "t": 40,
          "x": 30,
          "y": 0.3,
          "z": 0,
          "heading_deg": 0,
          "pose": "stand"
        }
      ],
      "attach_to": "",
      "attach_start_s": -7,
      "attach_end_s": 40,
      "attach_offset_xyz": [
        0,
        0,
        0
      ],
      "interaction": "Approaches only after the cars settle, stops well behind the rear bumper, and turns in place to point toward the cars."
    },
    {
      "id": "c008_r2",
      "label": "Resident at the south side",
      "kind": "human",
      "role": "South-side onlooker beside the rear car",
      "color": "teal",
      "length_m": 0.45,
      "width_m": 0.5,
      "height_m": 1.64,
      "keys": [
        {
          "t": -7,
          "x": 34,
          "y": -5.1,
          "z": 0,
          "heading_deg": 90,
          "pose": "stand"
        },
        {
          "t": 2,
          "x": 34,
          "y": -5.1,
          "z": 0,
          "heading_deg": 90,
          "pose": "walk"
        },
        {
          "t": 5,
          "x": 34,
          "y": -2.1,
          "z": 0,
          "heading_deg": 90,
          "pose": "stand"
        },
        {
          "t": 8,
          "x": 34,
          "y": -2.1,
          "z": 0,
          "heading_deg": 90,
          "pose": "point"
        },
        {
          "t": 24,
          "x": 34,
          "y": -2.1,
          "z": 0,
          "heading_deg": 90,
          "pose": "stand"
        },
        {
          "t": 40,
          "x": 34,
          "y": -2.1,
          "z": 0,
          "heading_deg": 90,
          "pose": "stand"
        }
      ],
      "attach_to": "",
      "attach_start_s": -7,
      "attach_end_s": 40,
      "attach_offset_xyz": [
        0,
        0,
        0
      ],
      "interaction": "Watches from a lateral offset without touching the car or entering its footprint."
    },
    {
      "id": "c008_r3",
      "label": "Resident watching from ahead",
      "kind": "human",
      "role": "South-side resident approaching the front of the collision",
      "color": "blue",
      "length_m": 0.45,
      "width_m": 0.5,
      "height_m": 1.8,
      "keys": [
        {
          "t": -7,
          "x": 44,
          "y": -4.8,
          "z": 0,
          "heading_deg": 90,
          "pose": "stand"
        },
        {
          "t": 2,
          "x": 44,
          "y": -4.8,
          "z": 0,
          "heading_deg": 90,
          "pose": "walk"
        },
        {
          "t": 5,
          "x": 44,
          "y": -1.8,
          "z": 0,
          "heading_deg": 90,
          "pose": "stand"
        },
        {
          "t": 6,
          "x": 44,
          "y": -1.8,
          "z": 0,
          "heading_deg": 135,
          "pose": "walk"
        },
        {
          "t": 8,
          "x": 42.5,
          "y": -0.3,
          "z": 0,
          "heading_deg": 135,
          "pose": "stand"
        },
        {
          "t": 9,
          "x": 42.5,
          "y": -0.3,
          "z": 0,
          "heading_deg": 180,
          "pose": "point"
        },
        {
          "t": 24,
          "x": 42.5,
          "y": -0.3,
          "z": 0,
          "heading_deg": 180,
          "pose": "stand"
        },
        {
          "t": 40,
          "x": 42.5,
          "y": -0.3,
          "z": 0,
          "heading_deg": 180,
          "pose": "stand"
        }
      ],
      "attach_to": "",
      "attach_start_s": -7,
      "attach_end_s": 40,
      "attach_offset_xyz": [
        0,
        0,
        0
      ],
      "interaction": "Uses an approach entirely ahead of the lead car, makes stationary turns, and watches from beyond its front bumper."
    },
    {
      "id": "c008_r4",
      "label": "North-side resident near the rear",
      "kind": "human",
      "role": "Onlooker approaching from the north sidewalk",
      "color": "beige",
      "length_m": 0.45,
      "width_m": 0.5,
      "height_m": 1.69,
      "keys": [
        {
          "t": -7,
          "x": 30.5,
          "y": 10.3,
          "z": 0,
          "heading_deg": -90,
          "pose": "stand"
        },
        {
          "t": 2,
          "x": 30.5,
          "y": 10.3,
          "z": 0,
          "heading_deg": -90,
          "pose": "walk"
        },
        {
          "t": 7,
          "x": 30.5,
          "y": 5.3,
          "z": 0,
          "heading_deg": -90,
          "pose": "walk"
        },
        {
          "t": 10,
          "x": 30.5,
          "y": 2.3,
          "z": 0,
          "heading_deg": -90,
          "pose": "stand"
        },
        {
          "t": 11,
          "x": 30.5,
          "y": 2.3,
          "z": 0,
          "heading_deg": -30,
          "pose": "point"
        },
        {
          "t": 24,
          "x": 30.5,
          "y": 2.3,
          "z": 0,
          "heading_deg": -30,
          "pose": "stand"
        },
        {
          "t": 40,
          "x": 30.5,
          "y": 2.3,
          "z": 0,
          "heading_deg": -30,
          "pose": "stand"
        }
      ],
      "attach_to": "",
      "attach_start_s": -7,
      "attach_end_s": 40,
      "attach_offset_xyz": [
        0,
        0,
        0
      ],
      "interaction": "Stops north of the rear approach and maintains separation from c008_r1."
    },
    {
      "id": "c008_r5",
      "label": "North-side resident beside the rear car",
      "kind": "human",
      "role": "Onlooker approaching a north-side viewing position",
      "color": "orange",
      "length_m": 0.45,
      "width_m": 0.5,
      "height_m": 1.73,
      "keys": [
        {
          "t": -7,
          "x": 35.5,
          "y": 10.3,
          "z": 0,
          "heading_deg": -90,
          "pose": "stand"
        },
        {
          "t": 2,
          "x": 35.5,
          "y": 10.3,
          "z": 0,
          "heading_deg": -90,
          "pose": "walk"
        },
        {
          "t": 7,
          "x": 35.5,
          "y": 5.3,
          "z": 0,
          "heading_deg": -90,
          "pose": "walk"
        },
        {
          "t": 10.2,
          "x": 35.5,
          "y": 2.1,
          "z": 0,
          "heading_deg": -90,
          "pose": "stand"
        },
        {
          "t": 12,
          "x": 35.5,
          "y": 2.1,
          "z": 0,
          "heading_deg": -90,
          "pose": "point"
        },
        {
          "t": 24,
          "x": 35.5,
          "y": 2.1,
          "z": 0,
          "heading_deg": -90,
          "pose": "stand"
        },
        {
          "t": 40,
          "x": 35.5,
          "y": 2.1,
          "z": 0,
          "heading_deg": -90,
          "pose": "stand"
        }
      ],
      "attach_to": "",
      "attach_start_s": -7,
      "attach_end_s": 40,
      "attach_offset_xyz": [
        0,
        0,
        0
      ],
      "interaction": "Observes the bumper-contact area from the north without approaching the vehicle body."
    },
    {
      "id": "c008_r6",
      "label": "North-side resident beside the lead car",
      "kind": "human",
      "role": "Onlooker approaching a separate north-side viewing position",
      "color": "navy",
      "length_m": 0.45,
      "width_m": 0.5,
      "height_m": 1.82,
      "keys": [
        {
          "t": -7,
          "x": 40,
          "y": 10.3,
          "z": 0,
          "heading_deg": -90,
          "pose": "stand"
        },
        {
          "t": 2,
          "x": 40,
          "y": 10.3,
          "z": 0,
          "heading_deg": -90,
          "pose": "walk"
        },
        {
          "t": 7,
          "x": 40,
          "y": 5.3,
          "z": 0,
          "heading_deg": -90,
          "pose": "walk"
        },
        {
          "t": 10.2,
          "x": 40,
          "y": 2.1,
          "z": 0,
          "heading_deg": -90,
          "pose": "stand"
        },
        {
          "t": 13,
          "x": 40,
          "y": 2.1,
          "z": 0,
          "heading_deg": -90,
          "pose": "point"
        },
        {
          "t": 24,
          "x": 40,
          "y": 2.1,
          "z": 0,
          "heading_deg": -90,
          "pose": "stand"
        },
        {
          "t": 40,
          "x": 40,
          "y": 2.1,
          "z": 0,
          "heading_deg": -90,
          "pose": "stand"
        }
      ],
      "attach_to": "",
      "attach_start_s": -7,
      "attach_end_s": 40,
      "attach_offset_xyz": [
        0,
        0,
        0
      ],
      "interaction": "Remains north of the lead car, separated from the adjacent resident by 4.5 metres center-to-center."
    }
  ],
  "acceptance_checks": [
    "Require exactly two collision cars and six resident onlookers; retain every actor from -7 through 40 seconds.",
    "At t=0 require tangent front-to-rear bumper contact at x=36.3, with no footprint overlap before or after contact.",
    "Require pre-contact closing speed near 0.4 m/s, a shared forward displacement of 0.25 metres, and no motion after 1.5 seconds.",
    "Verify residents do not leave their starting sidewalks until 2 seconds and never cross a car footprint.",
    "At 20 Hz verify ordinary people remain at least 0.6 metres apart and that all approach paths remain on mapped road or sidewalk surfaces.",
    "Require the cars to continue blocking |y|<=1.25 through 40 seconds; ego stays at x=12 with no release or invented recovery.",
    "Human review must approve the contact frame, shared settling motion and final crowd arrangement before any image generation."
  ],
  "assumptions": [
    "The police map and Image 2 establish road, sidewalk and building context only. The collision and resident crowd are newly authored counterfactual proposals.",
    "World time is -7..40 seconds at 20 Hz, with 941 inclusive samples and no loop. All support roots use z=0 relative to mapped ground.",
    "The request fixes two colliding cars. Six residents instantiate the unspecified multiple onlookers; no additional traffic vehicles are added.",
    "The lead car is initially stationary. The rear car slows from approximately 1.5 m/s to 0.4 m/s before contact. A modest contact impulse starts a shared 0.2 m/s roll, followed by braking to rest.",
    "Resident walking segments use approximately 0.9..1.1 m/s with eased starts and stops. Turns occur at stationary keys; pointing does not imply touching or aggression.",
    "No injuries, debris, emergency response or vehicle removal are proposed. Ego is separately controlled and stopped upstream before contact.",
    "Precise background-object footprints are not supplied and require human clearance review. After approval, Image 2.5 must edit original Image 2 rather than reconstruct its architecture; no approval or image generation has yet occurred."
  ]
}