diff --git a/messaging/__init__.py b/messaging/__init__.py
index 3ad41d8d650ee2..1628dd52442ab7 100644
--- a/messaging/__init__.py
+++ b/messaging/__init__.py
@@ -191,7 +191,7 @@ def update_msgs(self, cur_time: float, msgs: List[capnp.lib.capnp._DynamicStruct
       self.updated[s] = True
 
       if self.rcv_time[s] > 1e-5 and self.freq[s] > 1e-5 and (s not in self.non_polled_services) \
-        and (s not in self.ignore_average_freq) and (not SIMULATION):
+        and (s not in self.ignore_average_freq):
         self.recv_dts[s].append(cur_time - self.rcv_time[s])
 
       self.rcv_time[s] = cur_time
@@ -200,19 +200,23 @@ def update_msgs(self, cur_time: float, msgs: List[capnp.lib.capnp._DynamicStruct
       self.logMonoTime[s] = msg.logMonoTime
       self.valid[s] = msg.valid
 
-    for s in self.data:
-      # arbitrary small number to avoid float comparison. If freq is 0, we can skip the check
-      if self.freq[s] > 1e-5:
-        # alive if delay is within 10x the expected frequency
-        self.alive[s] = (cur_time - self.rcv_time[s]) < (10. / self.freq[s])
-
-        # alive if average frequency is higher than 90% of expected frequency
-        avg_dt = sum(self.recv_dts[s]) / AVG_FREQ_HISTORY
-        expected_dt = 1 / (self.freq[s] * 0.90)
-        self.alive[s] = self.alive[s] and (avg_dt < expected_dt)
-      else:
+      if SIMULATION:
         self.alive[s] = True
 
+    if not SIMULATION:
+      for s in self.data:
+        # arbitrary small number to avoid float comparison. If freq is 0, we can skip the check
+        if self.freq[s] > 1e-5:
+          # alive if delay is within 10x the expected frequency
+          self.alive[s] = (cur_time - self.rcv_time[s]) < (10. / self.freq[s])
+
+          # alive if average frequency is higher than 90% of expected frequency
+          avg_dt = sum(self.recv_dts[s]) / AVG_FREQ_HISTORY
+          expected_dt = 1 / (self.freq[s] * 0.90)
+          self.alive[s] = self.alive[s] and (avg_dt < expected_dt)
+        else:
+          self.alive[s] = True
+
   def all_alive(self, service_list=None) -> bool:
     if service_list is None:  # check all
       service_list = self.alive.keys()
diff --git a/messaging/socketmaster.cc b/messaging/socketmaster.cc
index 32c5f10f6418ef..b10133e430bd71 100644
--- a/messaging/socketmaster.cc
+++ b/messaging/socketmaster.cc
@@ -1,9 +1,13 @@
 #include <time.h>
 #include <assert.h>
+#include <stdlib.h>
+#include <string>
 
 #include "services.h"
 #include "messaging.h"
 
+const bool SIMULATION = (getenv("SIMULATION") != nullptr) && (std::string(getenv("SIMULATION")) == "1");
+
 static inline uint64_t nanos_since_boot() {
   struct timespec t;
   clock_gettime(CLOCK_BOOTTIME, &t);
@@ -103,11 +107,14 @@ void SubMaster::update_msgs(uint64_t current_time, std::vector<std::pair<std::st
     m->rcv_time = current_time;
     m->rcv_frame = frame;
     m->valid = m->event.getValid();
+    if (SIMULATION) m->alive = true;
   }
 
-  for (auto &kv : messages_) {
-    SubMessage *m = kv.second;
-    m->alive = (m->freq <= (1e-5) || ((current_time - m->rcv_time) * (1e-9)) < (10.0 / m->freq));
+  if (!SIMULATION) {
+    for (auto &kv : messages_) {
+      SubMessage *m = kv.second;
+      m->alive = (m->freq <= (1e-5) || ((current_time - m->rcv_time) * (1e-9)) < (10.0 / m->freq));
+    }
   }
 }