ADAS vehicle properties

We've added the following new ADAS properties to Android 14:

• Automatic emergency braking (AEB)
• Hands on detection (HOD)
• Lane centering assist (LCA)
• Forward collision warning (FCW)
• Blind spot warning (BSW)
• Lane departure warning (LDW)
• Lane keep assist (LKA)
• Emergency lane keep assist (ELKA)
• Standard cruise control (CC)
• Adaptive cruise control (ACC)

These new capabilities are illustrated in the following figure.

Figure 1. Supported ADAS features.

List of properties

To support these new features, a list of properties is added to Android 14. They're listed below.

Properties
ADAPTIVE_CRUISE_CONTROL_TARGET_TIME_GAP ADAPTIVE_CRUISE_CONTROL_LEAD_VEHICLE_DISTANCE AUTOMATIC_EMERGENCY_BRAKING_ENABLED AUTOMATIC_EMERGENCY_BRAKING_STATE BLIND_SPOT_WARNING_ENABLED BLIND_SPOT_WARNING_STATE CRUISE_CONTROL_ENABLED CRUISE_CONTROL_TYPE CRUISE_CONTROL_STATE CRUISE_CONTROL_COMMAND CRUISE_CONTROL_TARGET_SPEED EMERGENCY_LANE_KEEP_ASSIST_ENABLED EMERGENCY_LANE_KEEP_ASSIST_STATE	FORWARD_COLLISION_WARNING_ENABLED FORWARD_COLLISION_WARNING_STATE HANDS_ON_DETECTION_ENABLED HANDS_ON_DETECTION_DRIVER_STATE HANDS_ON_DETECTION_WARNING LANE_DEPARTURE_WARNING_ENABLED LANE_DEPARTURE_WARNING_STATE LANE_KEEP_ASSIST_ENABLED LANE_KEEP_ASSIST_STATE LANE_CENTERING_ASSIST_ENABLED LANE_CENTERING_ASSIST_COMMAND LANE_CENTERING_ASSIST_STATE

Design themes

The following design themes are applied to newly added properties.

Property	Description
ENABLED	Properties to indicate if a feature is enabled or disabled. Boolean properties in which true is enabled and false is disabled. Read and Write properties that can be implemented as Read-only.
STATE	Properties to communicate feature state through a list of predefined states. Int32 properties with defined enums. OTHER field to support backward compatibility. Read-only properties. Mirror or Global area types. Uses values defined in ErrorStates.aidl. Use the getSupportedEnumValues() API in AreaIdConfig.java.
Miscellaneous	COMMAND properties for features when user input is required. WARNING properties for when state can be represented separately. Other properties to support: Feature variations when applicable. Adjust feature settings when applicable.

State diagram examples

This section provides state diagrams for a subset of the supported ADAS features to demonstrate how the included properties work together. We've provided examples of the following features.

• Automatic emergency braking (AEB)
• Lane centering assist (LCA)
• Hands-on detection (HOD)

Automatic emergency braking

Two properties are defined for AEB as described in this table.

Property	Values
AUTOMATIC_EMERGENCY_BRAKING_ENABLED	VehiclePropertyType:BOOLEAN
AUTOMATIC_EMERGENCY_BRAKING_STATE Defined in AutomaticEmergencyBrakingState.aidl.	VehiclePropertyType:INT32 OTHER ENABLED ACTIVATED USER_OVERRIDE ErrorState

The following sample state diagram for AEB includes the supported states defined in AutomaticEmergencyBrakingState.aidl.

Figure 2. AEB states defined in AutomaticEmergencyBrakingState.aidl.

This figure provides an example of AEB when the USER_OVERRIDE state is not supported. Supported states should be specified through the getSupportedEnumValues() API in AreaIdConfig.java.

Figure 3. AEB when the USER_OVERRIDE state isn't supported.

In the AEB example illustrated in Figure 4, the error that causes AEB to become unavailable is highlighted. This demonstrates how values defined in ErrorState.aidl should be used. These errors don't result in an exception thrown by CarPropertyManager and are instead shared with apps in the same way as any other change to CarPropertyValue.

Figure 4. Error causes AEB to become unavailable.

Lane centering assist

Lane centering assist (LCA) provides three associated and defined properties.

Property	Values
LANE_CENTERING_ASSIST_ENABLED	VehiclePropertyType:BOOLEAN
LANE_CENTERING_ASSIST_STATE Defined in LaneCenteringAssistState.aidl	VehiclePropertyType:INT32 OTHER ENABLED ACTIVATION_REQUESTED ACTIVATED USER_OVERRIDE FORCED_DEACTIVATION_WARNING ErrorState
LANE_CENTERING_ASSIST_COMMAND Defined in LaneCenteringAssistCommand.aidl	VehiclePropertyType:INT32 ACTIVATE DEACTIVATE

The following state diagram illustrates LCA when all the defined states in LaneCenteringAssistState.aidl are supported. Green lines can either be a command initiated from the LANE_CENTERING_ASSIST_COMMAND (when implemented) or initiated through another mechanism in the vehicle and reflect a state change on the Android Automotive OS (AAOS).

Figure 5. LCA states defined in LaneCenteringAssistState.aidl.

This LCA example highlights an error that causes LCA to become unavailable. This demonstrates how to use the values defined in ErrorState.aidl. These errors don't result in CarPropertyManager throwing an error and are instead shared with apps in the same way that other changes to CarPropertyValue change are shared.

Figure 6. Error causes LCA to become unavailable.

Hands-on detection

These three associated properties are defined for hands-on detection (HOD).

Property	Description
HANDS_ON_DETECTION_ENABLED	VehiclePropertyType:BOOLEAN
HANDS_ON_DETECTION_STATE Defined in HandsOnDetectionDriverState.aidl	VehiclePropertyType:INT32 OTHER HANDS_ON HANDS_OFF ErrorState
HANDS_ON_DETECTION_WARNING Defined in HandsOnDetectionWarning.aidl	VehiclePropertyType:INT32 OTHER NO_WARNING WARNING ErrorState

Illustrated below is an example of HOD, in which all the defined states in HandsOnDetectionDriverState.aidl are supported.

Figure 7. HOD when all defined states in HandsOnDetectionDriverState.aidl are supported.

In addition to the HANDS_ON_DETECTION_STATE property, HOD also provides a separate warning property, HANDS_ON_DETECTION_WARNING. The state diagram for the HOD warning values is illustrated in Figure 8.

Figure 8. HOD when all defined values in HandsOnDetectionWarning.aidl are supported.