diff --git a/libraries/AP_HAL/CANIface.h b/libraries/AP_HAL/CANIface.h
index 77fda62e52..dca011f693 100644
--- a/libraries/AP_HAL/CANIface.h
+++ b/libraries/AP_HAL/CANIface.h
@@ -113,11 +113,11 @@ public:
         uint64_t deadline = 0;
         CANFrame frame;
         uint32_t index = 0;
-        bool loopback = false;
-        bool abort_on_error = false;
-        bool aborted = false;
-        bool pushed = false;
-        bool setup = false;
+        bool loopback:1;
+        bool abort_on_error:1;
+        bool aborted:1;
+        bool pushed:1;
+        bool setup:1;
 
         bool operator<(const CanTxItem& rhs) const
         {