Acts as a ribosome collision sensor, splitting the ribosome into its 2 subunits. Detects stalled/collided 70S ribosomes which it binds and splits by an ATP-hydrolysis driven conformational change. Acts upstream of the ribosome quality control system (RQC), a ribosome-associated complex that mediates the extraction of incompletely synthesized nascent chains from stalled ribosomes and their subsequent degradation. Probably generates substrates for RQC