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GRRF, a subsidiary of WP.29

The Working Party on Braking and Running Gear (GRRF) is the subsidiary body of the World Forum for Harmonization of Vehicle Regulations (WP.29) that prepares regulatory proposals on active safety, braking and running matters to WP.29. This group of experts conducts research and analysis to develop and propose active safety requirements of vehicles.

How it works

GRRF convenes officially twice a year and entrusts informal groups with specific problems that need to be solved urgently or that require special expertise.  More than 120 experts regularly participate to the GRRF sessions.


The Working Party is open to the governmental experts from any member Country of the United Nations, to any regional economic integration organization set up by member countries of the United Nations, and to experts of governmental organizations. Experts of non-governmental organizations (NGOs) may participate in a consultative capacity.  Final decisions are taken by Government representatives by vote at the World Forum (WP.29) level.

The work of the GRRF experts is transparent: all agendas, working documents and reports are available on this Internet website.

 Two sessions per year

Demonstration activities

Contact us

Don't hesitate to contact the GRRF secretariat by email at: grrf@unece.org

Latest news

September 2015

  • GRRF received a presentation and a demo of a vehicle equipped with the Remote Control Parking feature. GRRF agreed to report about issues related to cybersecurity to WP.29.
  • GRRF adopted several proposals amending existing Tyre regulations and an update of UN Regulation No. 55.
  • GRRF adopted amendments to UN Regulation No. 90 introducing provisions for the approval of replacement brake disks for L-category vehicles.
  • GRRF introduced EMC requirements in Regulation No. 78 (Motorcycle braking)

February 2015:

  • GRRF drafted an amendment to Regulation No. 109 (Retreaded tyres for commercial vehicles and their trailers) setting provisions regarding retreaded tyres for use in severe snow conditions.
  • GRRF reviewed the guidance provided by the IWG on ITS/AD answering to the GRRF request for guidance to WP.29 in November 2014 on advances innovations and self-driving technologies.
  • GRRF endorsed the proposal to establish an IWG on Automated Commanded Steering Functions (ACSF).
  • The expert from Japan, Vice Chair of GRRF, presented the regulatory development in his country on the mandatory fitting of advanced safety systems

November 2014:

  • WP.29/AC.3 adopted the Tyre GTR. 
  • GRRF requested guidance on the way it should work on advances innovations and self-driving technologies.

September 2014:

  • GRRF received a presentation by the automotive supplier industry about future innovations such as "valet parking" and "highway autopilot" (see here)
  • GRRF reviewed specific proposals for amendments to existing regulations that would allow the approval of self-steering systems e.g. on highways and decided to request guidance from policymakers.

June 2014:

WP.29, during its March 2014 session requested the UNECE secretariat to organize an Extraordinary Session of GRRF on 26 June 2014 in order: 
- to work on the draft Tyre GTR,  
- to efficiently incorporate the ongoing research results by the United States of America into the draft UN GTR on tyres.

March 2014:

UNECE's World Forum for Harmonization of Vehicle Regulation (WP.29) adopted technical provisions developed by GRRF within the last years concerning Automated Coupling Vehicles (ACV). Experts reported that each year, some drivers/operators are having accidents when manually coupling or de-coupling trailers or semi-trailers from the truck. GRRF defined safety provisions that would allow the deployment of automated coupling devices for trucks and their trailers, increasing safety and ensuring interoperability of towing equipment. 

February 2014:

GRRF received a presentation about Vehicle Platooning. More here: 76th session of GRRF

September 2013:

GRRF finalized the work on the definition of a test procedure for discriminating snow tyres for use in severe snow conditions for comercial vehicle tyres.

February 2013:

GRRF finalized the work on new amendments for the AEBS Regulation implementing crash avoidance provisions and the corresponding homologation test.

November 2012:

UNECE's World Forum for Harmonization of Vehicle Regulation (WP.29) adopted 2 new regulations that will enter into force in mid-2013 (i.e. 6 months after adoption) which were developed by GRRF within the last years:

Lane Departure Warning System (LDWS)

This system, fitted to trucks and coaches, is warning the driver, through an optical, acoustic or haptic warning, of an unintentional departure of his vehicle out of the travel lane. It thus aims at minimizing accidents by addressing three main causes of collisions: driver errors, distractions and drowsiness.

Advanced Emergency Braking System (AEBS)

The system, fitted to trucks and coaches, is using sensors to monitor the proximity of an object or a vehicle in front and detect situations where the relative speed and distance between the two vehicles suggests a collision will take place. The system provides the driver with a warning and activates the vehicle braking system to decelerate the vehicle with the purpose of avoiding or mitigating the severity of a collision in the event that the driver does not respond to the warning.
Here a video made at the occasion of a demonstration organized in Geneva in May 2011 prior to a special session of GRRF, introducing the system to the GRRF experts.