A navigational system for a host vehicle, the navigational system comprising: at least one processing device programmed to, when using a driving policy for providing at least one navigational change, wherein the at least one navigational change comprises a change in one or more of steering, braking, or acceleration of the host vehicle: receive a first output from a first data source associated with the host vehicle and a second output from a second data source associated with the host vehicle, wherein the first data source comprises at least one of a camera, a lidar, or a radar onboard the host vehicle, and the second data source comprises at least one of a camera, a lidar, or a radar onboard the host vehicle different from the first data source; and identify a representation of a target object in the first output, characterised in that the at least one processing device is further programmed to: determine whether a characteristic of the target object triggers at least one navigational safety constraint applicable to the at least one navigational change to be provided by the driving policy; when the at least one navigational safety constraint is not triggered by the characteristic of the target object, verify the identification of the representation of the target object based on a combination of the first output and the second output, and cause at least one navigational change in response to the verification; and when the at least one navigational safety constraint is triggered by the characteristic of the target object, verify the identification of the representation of the target object based on only the first output, and cause at least one navigational change in response to the verification. at least one processing device programmed to, when using a driving policy for providing at least one navigational change, wherein the at least one navigational change comprises a change in one or more of steering, braking, or acceleration of the host vehicle: receive a first output from a first data source associated with the host vehicle and a second output from a second data source associated with the host vehicle, wherein the first data source comprises at least one of a camera, a lidar, or a radar onboard the host vehicle, and the second data source comprises at least one of a camera, a lidar, or a radar onboard the host vehicle different from the first data source; and identify a representation of a target object in the first output, receive a first output from a first data source associated with the host vehicle and a second output from a second data source associated with the host vehicle, wherein the first data source comprises at least one of a camera, a lidar, or a radar onboard the host vehicle, and the second data source comprises at least one of a camera, a lidar, or a radar onboard the host vehicle different from the first data source; and identify a representation of a target object in the first output, characterised in that the at least one processing device is further programmed to: determine whether a characteristic of the target object triggers at least one navigational safety constraint applicable to the at least one navigational change to be provided by the driving policy; when the at least one navigational safety constraint is not triggered by the characteristic of the target object, verify the identification of the representation of the target object based on a combination of the first output and the second output, and cause at least one navigational change in response to the verification; and when the at least one navigational safety constraint is triggered by the characteristic of the target object, verify the identification of the representation of the target object based on only the first output, and cause at least one navigational change in response to the verification. determine whether a characteristic of the target object triggers at least one navigational safety constraint applicable to the at least one navigational change to be provided by the driving policy; when the at least one navigational safety constraint is not triggered by the characteristic of the target object, verify the identification of the representation of the target object based on a combination of the first output and the second output, and cause at least one navigational change in response to the verification; and when the at least one navigational safety constraint is triggered by the characteristic of the target object, verify the identification of the representation of the target object based on only the first output, and cause at least one navigational change in response to the verification.