Methods, systems, and devices are described for wireless communication at a user equipment (UE). In some examples, a base station may allocate, to a UE, time and/or frequency resources for transmitting physical random access channel (PRACH) signals. The resource allocation may be apportioned based on a type and class of PRACH signal. For instance, a UE may be assigned a first subset of resources to transmit regularly scheduled traffic and a second subset of resources to transmit on-demand traffic. Regularly scheduled traffic may include, for example, sensor measurements reported to the base station on a predetermined time interval (e.g., 24 hour time interval). In contrast, an on-demand traffic may include an impromptu transmission, initiated based on a detection of at least one reporting trigger (e.g., sensing an abnormality at the UE).