diff --git a/openpilot/starpilot/speed_limits/vision/speed_face.py b/openpilot/starpilot/speed_limits/vision/speed_face.py
index a805cabedf..ac4cd8195e 100644
--- a/openpilot/starpilot/speed_limits/vision/speed_face.py
+++ b/openpilot/starpilot/speed_limits/vision/speed_face.py
@@ -57,6 +57,40 @@ def crop(np, cv2, rgb256, box):
   return np.ascontiguousarray(np.clip(result, 0, 1).transpose(2, 0, 1))
 
 
+def warning_context_box(rgb256, box):
+  from openpilot.starpilot.speed_limits.vision import model
+
+  image = np.rint(rgb256.transpose(1, 2, 0) * np.float32(255)).astype(np.uint8)
+  hsv = cv2.cvtColor(image, cv2.COLOR_RGB2HSV)
+  hue, saturation, value = hsv[:, :, 0], hsv[:, :, 1], hsv[:, :, 2]
+  mask = ((hue >= model.REGULATORY_YELLOW_HUE_MIN) & (hue <= model.REGULATORY_YELLOW_HUE_MAX) &
+          (saturation >= model.REGULATORY_YELLOW_SAT_MIN) & (value >= model.REGULATORY_YELLOW_VALUE_MIN)).astype(np.uint8)
+  contours, _ = cv2.findContours(mask, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
+  center = (float((box[0] + box[2]) / 2), float((box[1] + box[3]) / 2))
+  matches = []
+  for contour in contours:
+    hull = cv2.convexHull(contour)
+    if (hull <= 0).any() or (hull >= 255).any():
+      continue
+    quad = cv2.approxPolyDP(hull, .02 * cv2.arcLength(hull, True), True)
+    if len(quad) != 4 or not cv2.isContourConvex(quad):
+      continue
+    points = quad.reshape(4, 2)
+    top, right = points[np.argmin(points[:, 1])], points[np.argmax(points[:, 0])]
+    bottom, left = points[np.argmax(points[:, 1])], points[np.argmin(points[:, 0])]
+    if (len({tuple(p) for p in (top, right, bottom, left)}) != 4 or
+        not (top[1] < min(left[1], right[1]) and bottom[1] > max(left[1], right[1]) and
+             left[0] < min(top[0], bottom[0]) and right[0] > max(top[0], bottom[0]))):
+      continue
+    x, y, width, height = cv2.boundingRect(hull)
+    if (cv2.pointPolygonTest(quad, center, False) >= 0 and
+        x < box[0] and y < box[1] and x + width > box[2] and y + height > box[3]):
+      outline = cv2.approxPolyDP(contour, .02 * cv2.arcLength(contour, True), True)
+      matches.append(np.asarray([x, y, x + width, y + height], np.float32)
+                     if len(outline) == 4 and cv2.isContourConvex(outline) else None)
+  return matches[0] if len(matches) == 1 else None
+
+
 class SpeedFaceVerifier:
   def __init__(self, path):
     self.net = None
@@ -123,6 +157,9 @@ class SpeedFaceVerifier:
     patch = crop(np, cv2, blob, box)
     if patch is None:
       return False
+    context_box = warning_context_box(blob, box)
+    if context_box is not None:
+      patch = crop(np, cv2, blob, context_box)
     started = time.monotonic()
     self.last_forward_count += 1
     try:
diff --git a/openpilot/starpilot/speed_limits/vision/tests/test_speed_warning_context.py b/openpilot/starpilot/speed_limits/vision/tests/test_speed_warning_context.py
new file mode 100644
index 0000000000..f499d0d3c9
--- /dev/null
+++ b/openpilot/starpilot/speed_limits/vision/tests/test_speed_warning_context.py
@@ -0,0 +1,112 @@
+"""Pure pixel geometry and single-call verifier behavior; no model loading."""
+import unittest
+from unittest import mock
+
+import numpy as np
+
+from openpilot.starpilot.speed_limits.vision import speed_face
+
+cv2 = speed_face.cv2
+
+
+class TestSpeedWarningContext(unittest.TestCase):
+  def setUp(self):
+    if cv2 is None:
+      self.skipTest("OpenCV is unavailable")
+
+  def image(self):
+    return np.zeros((256, 256, 3), np.uint8)
+
+  def blob(self, image):
+    return np.ascontiguousarray(image.transpose(2, 0, 1), dtype=np.float32) / np.float32(255)
+
+  def diamond(self, image, points=None):
+    points = points or [[128, 40], [216, 128], [128, 216], [40, 128]]
+    cv2.fillConvexPoly(image, np.asarray(points, np.int32), (255, 255, 0))
+    return image
+
+  def test_diamond_keeps_entire_original_box_support(self):
+    image = self.diamond(self.image())
+    box = np.array([75, 115, 150, 190], np.float32)
+    context = speed_face.warning_context_box(self.blob(image), box)
+    np.testing.assert_array_equal(context, [40, 40, 217, 217])
+    self.assertTrue(np.all(context[:2] < box[:2]) and np.all(context[2:] > box[2:]))
+
+  def test_circle_ellipse_rectangle_and_school_header_fall_back(self):
+    circle, ellipse, rectangle, header = [self.image() for _ in range(4)]
+    cv2.circle(circle, (128, 128), 85, (255, 255, 0), -1)
+    cv2.ellipse(ellipse, (128, 128), (95, 60), 20, 0, 360, (255, 255, 0), -1)
+    cv2.rectangle(rectangle, (40, 40), (216, 216), (255, 255, 0), -1)
+    cv2.rectangle(header, (70, 30), (180, 65), (255, 255, 0), -1)
+    for image in [circle, ellipse, rectangle, header]:
+      with self.subTest(kind=id(image)):
+        self.assertIsNone(speed_face.warning_context_box(self.blob(image), [100, 90, 155, 180]))
+
+  def test_border_outside_center_and_incomplete_containment_fall_back(self):
+    image = self.diamond(self.image())
+    self.assertIsNone(speed_face.warning_context_box(self.blob(image), [45, 45, 65, 65]))
+    self.assertIsNone(speed_face.warning_context_box(self.blob(image), [20, 100, 180, 180]))
+    touching = self.diamond(self.image(), [[128, 0], [240, 128], [128, 240], [16, 128]])
+    self.assertIsNone(speed_face.warning_context_box(self.blob(touching), [100, 100, 160, 160]))
+
+  def test_multiple_associations_are_ambiguous(self):
+    image = self.diamond(self.image())
+    contour = np.asarray([[128, 40], [216, 128], [128, 216], [40, 128]], np.int32)[:, None]
+    with mock.patch.object(speed_face.cv2, 'findContours', return_value=([contour, contour.copy()], None)):
+      self.assertIsNone(speed_face.warning_context_box(self.blob(image), [100, 100, 160, 160]))
+
+  def test_verifier_keeps_dense_binding_and_one_speed_request(self):
+    blob = self.blob(self.diamond(self.image()))
+    verifier = object.__new__(speed_face.SpeedFaceVerifier)
+    verifier.net = mock.Mock()
+    verifier.net.forward.return_value = [np.array([[-8]], np.float32)]
+    verifier.begin_frame()
+    candidate = (.8, 0, (1, 2, 3, 4))
+    box = np.array([100, 100, 160, 160], np.float32)
+    verifier._proposals[candidate] = [(blob, box, 77)]
+    self.assertTrue(verifier.reject_once(candidate))
+    self.assertEqual(verifier.last_dense_id, 77)
+    self.assertEqual(verifier.last_forward_count, 1)
+    verifier.net.forward.assert_called_once_with(['speed_face_logit'])
+    self.assertFalse(verifier.reject_once(candidate))
+    self.assertEqual(verifier.net.forward.call_count, 1)
+
+  def test_original_unresolved_and_invalid_crop_gates_precede_context(self):
+    verifier = object.__new__(speed_face.SpeedFaceVerifier)
+    verifier.net = mock.Mock()
+    candidate = (.8, 0, (1, 2, 3, 4))
+    for blob, box, invalid in [
+      (self.blob(self.image()), [10, 10, 12, 12], False),
+      (np.full((3, 256, 256), np.nan, np.float32), [10, 10, 30, 30], True),
+    ]:
+      verifier.begin_frame()
+      verifier._proposals[candidate] = [(blob, np.asarray(box, np.float32), 77)]
+      with mock.patch.object(speed_face, 'warning_context_box') as context:
+        if invalid:
+          with self.assertRaises(ValueError):
+            verifier.reject_once(candidate)
+        else:
+          self.assertFalse(verifier.reject_once(candidate))
+        context.assert_not_called()
+      verifier.net.forward.assert_not_called()
+      self.assertEqual(verifier.last_forward_count, 0)
+
+  def test_concave_outline_cannot_borrow_its_convex_hull_shape(self):
+    contour = np.asarray([[128, 40], [216, 128], [145, 128], [128, 216],
+                          [40, 128], [110, 128]], np.int32)[:, None]
+    hull = cv2.convexHull(contour)
+    quad = cv2.approxPolyDP(hull, .02 * cv2.arcLength(hull, True), True)
+    self.assertEqual(len(quad), 4)
+    self.assertTrue(cv2.isContourConvex(quad))
+    self.assertFalse(cv2.isContourConvex(contour))
+    with mock.patch.object(cv2, 'findContours', return_value=([contour], None)):
+      self.assertIsNone(speed_face.warning_context_box(self.blob(self.image()), [100, 100, 160, 160]))
+
+  def test_invalid_outline_does_not_resolve_multiple_hull_associations(self):
+    valid = np.asarray([[128, 40], [216, 128], [128, 216], [40, 128]], np.int32)[:, None]
+    invalid = np.asarray([[128, 40], [216, 128], [145, 128], [128, 216],
+                          [40, 128], [110, 128]], np.int32)[:, None]
+    for contours in ([invalid, valid], [valid, invalid]):
+      with self.subTest(invalid_first=contours[0] is invalid):
+        with mock.patch.object(cv2, 'findContours', return_value=(contours, None)):
+          self.assertIsNone(speed_face.warning_context_box(self.blob(self.image()), [100, 100, 160, 160]))
diff --git a/prebuilt.json b/prebuilt.json
index e6cd115899..3683b3bba7 100644
--- a/prebuilt.json
+++ b/prebuilt.json
@@ -1 +1 @@
-{"protected_inventory_sha256": "eaefaed6396e84e2a96158003a1f10e0b87b56f711676f4a86563ce20c1bc57e", "schema_version": 1}
+{"protected_inventory_sha256": "14e194326bcf0efef228ba09eaa7695844b0917bf1af867aa5ba510889396221", "schema_version": 1}