Methods, devices, and systems for congestion control in a wireless communications system. Some embodiments including receiving a plurality of zone configurations, receiving, for each of the plurality of zone configurations, a channel busy ration (CBR) threshold and a mapping of zone identities (IDs) to resource pools; and measuring a CBR of a resource pool with which the WTRU is currently configured. If the measured CBR meets a CBR threshold of a first zone configuration of the plurality, the WTRU is configured with the first zone configuration, with a zone ID based on the first zone configuration and apposition of the WTRU, and with a resource pool base on the mapping and configured zone ID.