diff --git a/selfdrive/car/interfaces.py b/selfdrive/car/interfaces.py
index 1746cbfb68..9dab21619b 100644
--- a/selfdrive/car/interfaces.py
+++ b/selfdrive/car/interfaces.py
@@ -74,7 +74,7 @@ class CarInterfaceBase(ABC):
   def get_std_params(candidate, fingerprint):
     ret = car.CarParams.new_message()
     ret.carFingerprint = candidate
-    ret.unsafeMode = 0
+    ret.unsafeMode = 0  # see safety_declarations.h for allowed values
 
     # standard ALC params
     ret.steerControlType = car.CarParams.SteerControlType.torque