diff --git a/selfdrive/locationd/test/test_lagd.py b/selfdrive/locationd/test/test_lagd.py
index 579bf9567a..19340bd347 100644
--- a/selfdrive/locationd/test/test_lagd.py
+++ b/selfdrive/locationd/test/test_lagd.py
@@ -16,17 +16,25 @@ MAX_ERR_FRAMES = 1
 DT = 0.05
 
 
-def process_messages(mocker, estimator, lag_frames, n_frames, vego=20.0):
+def process_messages(mocker, estimator, lag_frames, n_frames, vego=20.0, rejection_threshold=0.0):
   class ZeroMock(mocker.Mock):
     def __getattr__(self, *args):
       return 0
 
   for i in range(n_frames):
     t = i * estimator.dt
-    desired_cuvature = np.cos(t) / (vego ** 2)
-    actual_yr = np.cos(t - lag_frames * estimator.dt) / vego
+    desired_la = np.cos(t)
+    actual_la = np.cos(t - lag_frames * estimator.dt)
+
+    # if sample is masked out, set it to desired value (no lag)
+    rejected = random.uniform(0, 1) < rejection_threshold
+    if rejected:
+      actual_la = desired_la
+
+    desired_cuvature = desired_la / (vego ** 2)
+    actual_yr = actual_la / vego
     msgs = [
-      (t, "carControl", mocker.Mock(latActive=True)),
+      (t, "carControl", mocker.Mock(latActive=not rejected)),
       (t, "carState", mocker.Mock(vEgo=vego, steeringPressed=False)),
       (t, "controlsState", mocker.Mock(desiredCurvature=desired_cuvature,
                                         lateralControlState=mocker.Mock(which=mocker.Mock(return_value='debugControlState'), debugControlState=ZeroMock()))),
@@ -105,6 +113,13 @@ class TestLagd:
         assert np.allclose(msg.liveDelay.lateralDelayEstimate, lag_frames * DT, atol=0.01)
         assert msg.liveDelay.validBlocks == BLOCK_NUM_NEEDED
 
+  def test_estimator_masking(self, mocker):
+    mocked_CP, lag_frames = mocker.Mock(steerActuatorDelay=0.8), random.randint(1, 19)
+    estimator = LateralLagEstimator(mocked_CP, DT, min_recovery_buffer_sec=0.0, min_yr=0.0, min_valid_block_count=1)
+    process_messages(mocker, estimator, lag_frames, (int(MIN_OKAY_WINDOW_SEC / DT) + BLOCK_SIZE) * 2, rejection_threshold=0.4)
+    msg = estimator.get_msg(True)
+    assert np.allclose(msg.liveDelay.lateralDelayEstimate, lag_frames * DT, atol=0.01)
+
   @pytest.mark.skipif(PC, reason="only on device")
   @pytest.mark.timeout(30)
   def test_estimator_performance(self, mocker):