diff --git a/selfdrive/controls/lib/alertmanager.py b/selfdrive/controls/lib/alertmanager.py
index 870d8d4b7e..6eaa86d3ec 100644
--- a/selfdrive/controls/lib/alertmanager.py
+++ b/selfdrive/controls/lib/alertmanager.py
@@ -1,24 +1,21 @@
 import os
 import copy
 import json
+from typing import List, Optional
 
 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
 from selfdrive.swaglog import cloudlog
 
-AlertSize = log.ControlsState.AlertSize
-AlertStatus = log.ControlsState.AlertStatus
-VisualAlert = car.CarControl.HUDControl.VisualAlert
-AudibleAlert = car.CarControl.HUDControl.AudibleAlert
-
 
 with open(os.path.join(BASEDIR, "selfdrive/controls/lib/alerts_offroad.json")) as f:
   OFFROAD_ALERTS = json.load(f)
 
 
-def set_offroad_alert(alert, show_alert, extra_text=None):
+def set_offroad_alert(alert: str, show_alert: bool, extra_text: Optional[str] = None) -> None:
   if show_alert:
     a = OFFROAD_ALERTS[alert]
     if extra_text is not None:
@@ -29,19 +26,30 @@ def set_offroad_alert(alert, show_alert, extra_text=None):
     Params().delete(alert)
 
 
-class AlertManager():
+class AlertManager:
 
   def __init__(self):
-    self.activealerts = []
+    self.activealerts: List[Alert] = []
+    self.clear_current_alert()
 
-  def alert_present(self):
+  def alert_present(self) -> bool:
     return len(self.activealerts) > 0
 
-  def add_many(self, frame, alerts, enabled=True):
+  def clear_current_alert(self) -> None:
+    self.alert_type: str = ""
+    self.alert_text_1: str = ""
+    self.alert_text_2: str = ""
+    self.alert_status = log.ControlsState.AlertStatus.normal
+    self.alert_size = log.ControlsState.AlertSize.none
+    self.visual_alert = car.CarControl.HUDControl.VisualAlert.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:
     for a in alerts:
       self.add(frame, a, enabled=enabled)
 
-  def add(self, frame, alert, enabled=True):
+  def add(self, frame: int, alert: Alert, enabled: bool = True) -> None:
     added_alert = copy.copy(alert)
     added_alert.start_time = frame * DT_CTRL
 
@@ -54,26 +62,18 @@ class AlertManager():
     # sort by priority first and then by start_time
     self.activealerts.sort(key=lambda k: (k.alert_priority, k.start_time), reverse=True)
 
-  def process_alerts(self, frame):
+  def process_alerts(self, frame: int) -> None:
     cur_time = frame * DT_CTRL
 
     # first get rid of all the expired alerts
     self.activealerts = [a for a in self.activealerts if a.start_time +
                          max(a.duration_sound, a.duration_hud_alert, a.duration_text) > cur_time]
 
-    current_alert = self.activealerts[0] if self.alert_present() else None
-
     # start with assuming no alerts
-    self.alert_type = ""
-    self.alert_text_1 = ""
-    self.alert_text_2 = ""
-    self.alert_status = AlertStatus.normal
-    self.alert_size = AlertSize.none
-    self.visual_alert = VisualAlert.none
-    self.audible_alert = AudibleAlert.none
-    self.alert_rate = 0.
-
-    if current_alert:
+    self.clear_current_alert()
+
+    current_alert = self.activealerts[0] if self.alert_present() else None
+    if current_alert is not None:
       self.alert_type = current_alert.alert_type
 
       if current_alert.start_time + current_alert.duration_sound > cur_time: