diff --git a/selfdrive/controls/controlsd.py b/selfdrive/controls/controlsd.py
index d029650aafcb56..fb58d56472136b 100755
--- a/selfdrive/controls/controlsd.py
+++ b/selfdrive/controls/controlsd.py
@@ -614,7 +614,7 @@ def publish_logs(self, CS, start_time, actuators, lac_log):
 
     clear_event = ET.WARNING if ET.WARNING not in self.current_alert_types else None
     alerts = self.events.create_alerts(self.current_alert_types, [self.CP, self.sm, self.is_metric])
-    self.AM.add_many(self.sm.frame, alerts, self.enabled)
+    self.AM.add_many(self.sm.frame, alerts)
     self.AM.process_alerts(self.sm.frame, clear_event)
     CC.hudControl.visualAlert = self.AM.visual_alert
 
diff --git a/selfdrive/controls/lib/alertmanager.py b/selfdrive/controls/lib/alertmanager.py
index 22d7f3eac473da..c8e702c5c7c1d0 100644
--- a/selfdrive/controls/lib/alertmanager.py
+++ b/selfdrive/controls/lib/alertmanager.py
@@ -8,7 +8,6 @@
 from cereal import car, log
 from common.basedir import BASEDIR
 from common.params import Params
-from common.realtime import DT_CTRL
 from selfdrive.controls.lib.events import Alert
 
 
@@ -33,12 +32,14 @@ class AlertEntry:
   start_frame: int = -1
   end_frame: int = -1
 
+  def active(self, frame: int) -> bool:
+    return frame <= self.end_frame
 
 class AlertManager:
 
   def __init__(self):
     self.reset()
-    self.activealerts: Dict[str, AlertEntry] = defaultdict(AlertEntry)
+    self.alerts: Dict[str, AlertEntry] = defaultdict(AlertEntry)
 
   def reset(self) -> None:
     self.alert: Optional[Alert] = None
@@ -51,25 +52,27 @@ def reset(self) -> None:
     self.audible_alert = car.CarControl.HUDControl.AudibleAlert.none
     self.alert_rate: float = 0.
 
-  def add_many(self, frame: int, alerts: List[Alert], enabled: bool = True) -> None:
+  def add_many(self, frame: int, alerts: List[Alert]) -> None:
     for alert in alerts:
-      self.activealerts[alert.alert_type].alert = alert
-      self.activealerts[alert.alert_type].start_frame = frame
-      self.activealerts[alert.alert_type].end_frame = frame + int(alert.duration / DT_CTRL)
+      key = alert.alert_type
+      self.alerts[key].alert = alert
+      if not self.alerts[key].active(frame):
+        self.alerts[key].start_frame = frame
+      min_end_frame = self.alerts[key].start_frame + alert.duration
+      self.alerts[key].end_frame = max(frame + 1, min_end_frame)
 
   def process_alerts(self, frame: int, clear_event_type=None) -> None:
     current_alert = AlertEntry()
-    for k, v in self.activealerts.items():
+    for k, v in self.alerts.items():
       if v.alert is None:
         continue
 
-      if v.alert.event_type == clear_event_type:
-        self.activealerts[k].end_frame = -1
+      if clear_event_type is not None and v.alert.event_type == clear_event_type:
+        self.alerts[k].end_frame = -1
 
       # sort by priority first and then by start_frame
-      active = self.activealerts[k].end_frame > frame
       greater = current_alert.alert is None or (v.alert.priority, v.start_frame) > (current_alert.alert.priority, current_alert.start_frame)
-      if active and greater:
+      if v.active(frame) and greater:
         current_alert = v
 
     # clear current alert
diff --git a/selfdrive/controls/lib/events.py b/selfdrive/controls/lib/events.py
index e278a00cc5ffa8..6254786b83b362 100644
--- a/selfdrive/controls/lib/events.py
+++ b/selfdrive/controls/lib/events.py
@@ -123,7 +123,7 @@ def __init__(self,
     self.visual_alert = visual_alert
     self.audible_alert = audible_alert
 
-    self.duration = duration
+    self.duration = int(duration / DT_CTRL)
 
     self.alert_rate = alert_rate
     self.creation_delay = creation_delay
diff --git a/selfdrive/controls/lib/tests/test_alertmanager.py b/selfdrive/controls/lib/tests/test_alertmanager.py
new file mode 100755
index 00000000000000..bb6664303b7e24
--- /dev/null
+++ b/selfdrive/controls/lib/tests/test_alertmanager.py
@@ -0,0 +1,45 @@
+#!/usr/bin/env python3
+import random
+import unittest
+
+from selfdrive.controls.lib.events import Alert, EVENTS
+from selfdrive.controls.lib.alertmanager import AlertManager
+
+
+class TestAlertManager(unittest.TestCase):
+
+  def test_duration(self):
+    """
+      Enforce that an alert lasts for max(alert duration, duration the alert is added)
+    """
+    for duration in range(1, 100):
+      alert = None
+      while not isinstance(alert, Alert):
+        event = random.choice([e for e in EVENTS.values() if len(e)])
+        alert = random.choice(list(event.values()))
+
+      alert.duration = duration
+
+      # check two cases:
+      # - alert is added to AM for <= the alert's duration
+      # - alert is added to AM for > alert's duration
+      for greater in (True, False):
+        if greater:
+          add_duration = duration + random.randint(1, 10)
+        else:
+          add_duration = random.randint(1, duration)
+        show_duration = max(duration, add_duration)
+
+        AM = AlertManager()
+        for frame in range(duration+10):
+          if frame < add_duration:
+            AM.add_many(frame, [alert, ])
+          AM.process_alerts(frame)
+
+          shown = AM.alert is not None
+          should_show = frame <= show_duration
+          self.assertEqual(shown, should_show, msg=f"{frame=} {add_duration=} {duration=}")
+
+
+if __name__ == "__main__":
+  unittest.main()
diff --git a/selfdrive/test/process_replay/ref_commit b/selfdrive/test/process_replay/ref_commit
index 1c523cd77e04c2..c162de2bb26bf2 100644
--- a/selfdrive/test/process_replay/ref_commit
+++ b/selfdrive/test/process_replay/ref_commit
@@ -1 +1 @@
-c09fc7b1409529a9991428845ee14f0e37d95b2d
\ No newline at end of file
+0ae46ae318a63476d8905aa0c32b0e587177868a
\ No newline at end of file