ISO 26684:2015 specifies the concept of operation, system requirements, and test methods for cooperative intersection signal information and violation warning systems (CIWS) at signalized intersections. CIWS are intended to reduce the likelihood of crash injury, damage, and fatality by enhancing the capability of drivers to avoid crash situations at signalized intersections.

The scope of CIWS standardization includes basic functions, functional requirements, performance requirements, information contents, and test methods.

The characteristics of the technologies used to communicate between the signal controller and the vehicles are not addressed by this International Standard nor are the behavioural responses by drivers, the various capabilities of vehicles on the road, or the multitude of combinations of these two characteristics.