You must mean L3 since L4's ADS is not allowed to disengage. If L4 goes beyond its ODD scope or any DDT failure it can pull over and stop driving but it can't just disengage or ask for help driving...... An AV that disengages every 1 mile is still level 4 regardless of the error rate. An ADAS that disengages every 10 million miles is still L2 regardless of how insignificant the error rate is.....