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Automatically Commanded Steering Functions (ACSF)

This page provides access to the documents and meetings of the Automatically Commanded Steering Informal Group.
No new meetings have been scheduled as of today.

UN Regulation No. 79 contains provisions for the use of an “automatically commanded steering function” (i.e., automated steering) that restricts use to speeds up to 10 km/h. In light of automated vehicle systems (such as lane keeping assistance) that propose automated steering control at higher speeds, including on highways, the ACSF informal working group was formed to consider amending UN R79 to enable the approval of such higher speed automated steering systems.

In addition to the core system capabilities and performance provisions, the group expects to consider malfunction warning requirements and system testing under periodic technical inspections.


The ACSF informal group has developed a system of categories for the regulation of automated steering systems. These categories should not be confused with the levels of automation developed notably under SAE J3016. These categories define specific system capabilities in executing steering maneuvers.

Category C addresses systems that assist the driver with a lane change maneuver following a request by the driver. The driver is responsible for the decision to actuate a lane change (e.g., checking to ensure that the conditions are safe for changing lanes) and thus for the object and event detection and response (OEDR). In this regard, the driver responsibilities in using a Category C ACSF system are identical to those of a driver changing lanes manually. Strictly defined, the Category C system simply automates the lane change as a convenience to the driver. In practice, these systems include OEDR capabilities in order to improve road safety; however, the state of technology cannot ensure 100% reliability under all conditions and therefore requires human supervision. Categories B1 + C constitute an SAE Level 2 partially automated system. Rearward sensing systems (built upon advances to blind-spot detection systems) provide supplemental benefits, but do not shift the automation to Level 3. (reference ACSF-13-11)


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