Some OBD-II apps allow users to assign a priority to each request for PID/sensor data. From my limited understanding of the CAN protocol, priority is determined from the message identifier alone. But car manufacturers add higher-layer protocols over CAN. Does anyone know whether Toyota adds something that assigns priority to CAN nodes (so presumably the OBD node would be assigned a low priority, then OBD apps could rank requests within this low priority)? Otherwise, is there a safety risk through overloading the vehicle bus with multiple (high-priority, OBD) data requests if logging data while driving?