diff --git a/automotive/vehicle/aidl/aidl_api/android.hardware.automotive.vehicle/current/android/hardware/automotive/vehicle/TrailerState.aidl b/automotive/vehicle/aidl/aidl_api/android.hardware.automotive.vehicle/current/android/hardware/automotive/vehicle/TrailerState.aidl
new file mode 100644
index 0000000..2491340
--- /dev/null
+++ b/automotive/vehicle/aidl/aidl_api/android.hardware.automotive.vehicle/current/android/hardware/automotive/vehicle/TrailerState.aidl
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+///////////////////////////////////////////////////////////////////////////////
+// THIS FILE IS IMMUTABLE. DO NOT EDIT IN ANY CASE.                          //
+///////////////////////////////////////////////////////////////////////////////
+
+// This file is a snapshot of an AIDL file. Do not edit it manually. There are
+// two cases:
+// 1). this is a frozen version file - do not edit this in any case.
+// 2). this is a 'current' file. If you make a backwards compatible change to
+//     the interface (from the latest frozen version), the build system will
+//     prompt you to update this file with `m <name>-update-api`.
+//
+// You must not make a backward incompatible change to any AIDL file built
+// with the aidl_interface module type with versions property set. The module
+// type is used to build AIDL files in a way that they can be used across
+// independently updatable components of the system. If a device is shipped
+// with such a backward incompatible change, it has a high risk of breaking
+// later when a module using the interface is updated, e.g., Mainline modules.
+
+package android.hardware.automotive.vehicle;
+@Backing(type="int") @VintfStability
+enum TrailerState {
+  UNKNOWN = 0,
+  NOT_PRESENT = 1,
+  PRESENT = 2,
+  ERROR = 3,
+}
diff --git a/automotive/vehicle/aidl/aidl_api/android.hardware.automotive.vehicle/current/android/hardware/automotive/vehicle/VehicleProperty.aidl b/automotive/vehicle/aidl/aidl_api/android.hardware.automotive.vehicle/current/android/hardware/automotive/vehicle/VehicleProperty.aidl
index 2505dbd..5cd814c 100644
--- a/automotive/vehicle/aidl/aidl_api/android.hardware.automotive.vehicle/current/android/hardware/automotive/vehicle/VehicleProperty.aidl
+++ b/automotive/vehicle/aidl/aidl_api/android.hardware.automotive.vehicle/current/android/hardware/automotive/vehicle/VehicleProperty.aidl
@@ -204,4 +204,5 @@
   EV_CHARGE_SWITCH = 287313730,
   EV_CHARGE_TIME_REMAINING = 289410883,
   EV_REGENERATIVE_BRAKING_STATE = 289410884,
+  TRAILER_PRESENT = 289410885,
 }
diff --git a/automotive/vehicle/aidl/android/hardware/automotive/vehicle/TrailerState.aidl b/automotive/vehicle/aidl/android/hardware/automotive/vehicle/TrailerState.aidl
new file mode 100644
index 0000000..fd42062
--- /dev/null
+++ b/automotive/vehicle/aidl/android/hardware/automotive/vehicle/TrailerState.aidl
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.hardware.automotive.vehicle;
+
+/**
+ * Used by the trailer present property to enumerate the current state
+ * of the trailer.
+ */
+@VintfStability
+@Backing(type="int")
+enum TrailerState {
+    UNKNOWN = 0,
+    NOT_PRESENT = 1,
+    PRESENT = 2,
+    ERROR = 3,
+}
diff --git a/automotive/vehicle/aidl/android/hardware/automotive/vehicle/VehicleProperty.aidl b/automotive/vehicle/aidl/android/hardware/automotive/vehicle/VehicleProperty.aidl
index 87b4802..9dbeae2 100644
--- a/automotive/vehicle/aidl/android/hardware/automotive/vehicle/VehicleProperty.aidl
+++ b/automotive/vehicle/aidl/android/hardware/automotive/vehicle/VehicleProperty.aidl
@@ -2803,4 +2803,16 @@
      */
     EV_REGENERATIVE_BRAKING_STATE = 0x0F44 + 0x10000000 + 0x01000000
             + 0x00400000, // VehiclePropertyGroup:SYSTEM,VehicleArea:GLOBAL,VehiclePropertyType:INT32
+
+    /**
+     * Indicates if there is a trailer present or not.
+     *
+     * Returns the trailer state of the car.
+     *
+     * @change_mode VehiclePropertyChangeMode:ON_CHANGE
+     * @access VehiclePropertyAccess:READ
+     * @data_enum TrailerState
+     */
+    TRAILER_PRESENT = 0x0F45 + 0x10000000 + 0x01000000
+            + 0x00400000, // VehiclePropertyGroup:SYSTEM,VehicleArea:GLOBAL,VehiclePropertyType:INT32
 }