A method of a wireless communication by a first user equipment, UE, comprising: receiving a safety message from a second UE, wherein the received safety message includes a cluster indicator (802; 852) that indicates whether the received safety message is a first safety message type or a second safety message type , wherein the cluster indicator is a bit indicator and wherein the first safety message type contains location, speed and heading information about a single UE and the second safety message type contains location and motion information about a cluster of multiple UEs and a leader UE identifier associated with the cluster; determining whether the received safety message is the first safety message type or the second safety message type based on the cluster indicator (802; 852) included in the safety message; determining whether a proximity condition between the first UE and the second UE is satisfied by determining whether a distance between the first UE and the second UE is less than a threshold and by determining a relative motion between the first UE and the second UE; and determining a mode of the first UE, the mode being a standalone mode or a cluster member mode; wherein, if the first UE is in a cluster member mode, determining whether an identifier in the received safety message matches a leader UE identifier associated with the cluster of UEs associated with the first UE; storing information related to determining whether the proximity condition is satisfied based on the determination of whether the identifier matches the leader UE identifier; and determining whether to leave the cluster of UEs based on whether the proximity condition is satisfied. receiving a safety message from a second UE, wherein the received safety message includes a cluster indicator (802; 852) that indicates whether the received safety message is a first safety message type or a second safety message type , wherein the cluster indicator is a bit indicator and wherein the first safety message type contains location, speed and heading information about a single UE and the second safety message type contains location and motion information about a cluster of multiple UEs and a leader UE identifier associated with the cluster; determining whether the received safety message is the first safety message type or the second safety message type based on the cluster indicator (802; 852) included in the safety message; determining whether a proximity condition between the first UE and the second UE is satisfied by determining whether a distance between the first UE and the second UE is less than a threshold and by determining a relative motion between the first UE and the second UE; and determining a mode of the first UE, the mode being a standalone mode or a cluster member mode; wherein, if the first UE is in a cluster member mode, determining whether an identifier in the received safety message matches a leader UE identifier associated with the cluster of UEs associated with the first UE; storing information related to determining whether the proximity condition is satisfied based on the determination of whether the identifier matches the leader UE identifier; and determining whether to leave the cluster of UEs based on whether the proximity condition is satisfied. <EOS>