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Vehicle properties
ADAS & driver assistance

FORWARD_COLLISION_WARNING_ENABLED

What it is

Enable or disable Forward Collision Warning (FCW).

Set true to enable FCW and false to disable FCW. When FCW is enabled, the ADAS system in the vehicle should be turned on and monitoring for potential collisions.

In general, FORWARD_COLLISION_WARNING_ENABLED should always return true or false. If the feature is not available due to some temporary state, such as the vehicle speed being too low, that information must be conveyed through the ErrorState values in the FORWARD_COLLISION_WARNING_STATE property.

This property is defined as VehiclePropertyAccess.READ_WRITE, but OEMs have the option to implement it as VehiclePropertyAccess.READ only.

How the ID is built

A property ID is a 32-bit value packing four fields. Reading 0x11201002 apart:

FieldMaskValueMeans
Group0xf00000000x10000000SYSTEM
Area0x0f0000000x01000000GLOBAL
Type0x00ff00000x00200000BOOLEAN
Ordinal0x0000ffff0x000010020x1002

Reading it from an app

CarPropertyManager mgr = (CarPropertyManager)
        car.getCarManager(Car.PROPERTY_SERVICE);

boolean value =
        mgr.getBooleanProperty(VehiclePropertyIds.FORWARD_COLLISION_WARNING_ENABLED, 0);

This property can be read and written, though an OEM may implement it as read-only. It fires a callback whenever the value changes.