UN R78 Supplement 2 (05 series) · UNECE Regulation No. 78 (ECE R78) — Uniform provisions concerning the approval of vehicles of categories L1, L2, L3, L4 and L5 with regard to braking.
UN R78 — Supplement 2 to the 05 series of amendments
Supplement 1 → 2
- What changed
- New paragraph 2.34. defines “automatically commanded braking”.
- The braking signal rules in paragraphs 5.1.17.2. and 5.1.17.3. now also cover automatically commanded braking.
- The signal may now also be suppressed when the deceleration demand falls below 1.3 m/s² or the value that generated it, whichever is lower.
- Why
- The proposal aims to further align the stop lamp signal provisions of UN Regulation No. 78 with UN Regulation No. 13-H.
- The aim is a consistent stop lamp behaviour across vehicle categories, so that road users behind a braking vehicle of any category are not confused.
- The proposal also aims to enable the stop lamp when automatically commanded braking causes the vehicle deceleration.
Q1What changed4 changes
New definition of automatically commanded braking (para. 2.34.)
New paragraph 2.34. defines “automatically commanded braking”. It is a function within a complex electronic control system. In this function, the braking system(s) or brakes of certain axles are actuated to generate vehicle retardation. The actuation can occur with or without a direct action of the driver. The actuation results from the automatic evaluation of on-board initiated information. Paragraphs 5.1.17.2. and 5.1.17.3. now use this term.
Braking signal for automatically commanded braking (para. 5.1.17.2.)
Paragraph 5.1.17.2. now applies to vehicles equipped with automatically commanded braking and/or electric regenerative braking systems that produce a retarding force. Before this supplement, the paragraph named only electric regenerative braking systems. Release of the accelerator control is now given only as an example of when the retarding force occurs. In the table of paragraph 5.1.17.2., the words “Vehicle deceleration by regenerative braking” now read “Vehicle deceleration by automatically commanded braking and/or regenerative braking”. Under the table, the signal may be generated when this vehicle deceleration is 1.3 m/s² or less, and must be generated above 1.3 m/s².
Keeping and suppressing the braking signal (para. 5.1.17.3.)
Once generated, the signal must be kept as long as a deceleration demand by the automatically commanded braking and/or electric regenerative braking persists. Before this supplement, this rule named only the electric regenerative braking. The signal may be suppressed at standstill, as before. It may now also be suppressed when the deceleration demand falls below 1.3 m/s² or the value that generated the signal, whichever is lower.
Q2Why it changed
- Proposed by
- Expert from the International Motorcycle Manufacturers Association
- Working party
- GRVA, 14th session (September 2022)
Reasons
The proposal aims to further align the stop lamp signal provisions in UN Regulation No. 78 with UN Regulation No. 13-H.
Source
“The aim of this proposal is to further align the stop lamp signal provisions in UN Regulation No. 78 with UN Regulation No. 13-H”
The alignment aims to keep a consistent stop lamp behaviour across different vehicle categories. In this way, it aims to avoid confusion to road users who drive behind a braking vehicle, regardless of its category.
Source
“to keep a consistent stop lamp behaviour across different vehicle categories and therefore avoid confusion to road users driving behind a braking vehicle, regardless of its category”
One aim is to enable the activation of the stop lamp when automatically commanded braking causes the vehicle deceleration.
Source
“To enable the activation of the stop lamp when the vehicle deceleration is caused by the automatically commanded braking.”
Another aim is to align the criteria in paragraph 5.1.17.2. with the latest amendments to paragraph 5.2.22.2. of UN Regulation No. 13-H. GRVA adopted those amendments at its twelfth session in January 2022.
Source
“To align the criteria in paragraph 5.1.17.2. with the latest amendments to paragraph 5.2.22.2. of UN Regulation 13-H, as adopted at the twelfth session of GRVA in January 2022”
Document trail
- 2022-07ProposalECE/TRANS/WP.29/GRVA/2022/26Proposal by IMMA for the 14th GRVA session
- —Working party adoptsECE/TRANS/WP.29/GRVA/14Session report, para. 110
- 2022-12Sent to WP.29ECE/TRANS/WP.29/2023/10Text that GRVA sent to WP.29 and AC.1
- 2023-03WP.29 adoptsECE/TRANS/WP.29/1171Adopted at the 189th session (session report, para. 127)
- 2023-09-24In forceC.N.416.2023.TREATIES-XI.B.16.78UN depositary notification
Q3Who is affected
Vehicle manufacturer
- Check which of your vehicles have a function that meets the definition of “automatically commanded braking” in paragraph 2.34.
- For vehicles with automatically commanded braking, make sure that the braking signal meets paragraphs 5.1.17.2. and 5.1.17.3.
- Decide whether to use the new signal suppression case of paragraph 5.1.17.3.
Component supplier
- Check your braking signal logic for automatically commanded braking against paragraphs 5.1.17.2. and 5.1.17.3.
- Check the threshold of the new suppression case: the lower of 1.3 m/s² and the value that generated the signal.
- Give the vehicle manufacturer updated system documents for paragraphs 5.1.17.2. and 5.1.17.3.
Technical service / Approval authority
- When you assess a vehicle, check if a function meets the definition of “automatically commanded braking” in paragraph 2.34.
- Update your checklists for paragraphs 5.1.17.2. and 5.1.17.3. to include automatically commanded braking.
- Add the new signal suppression case of paragraph 5.1.17.3. to your checklists.
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ⓘ This report gives advice only. It is not legal or type-approval advice.