UN R53 Supplement 7 (02 series) · UNECE Regulation No. 53 (ECE R53) — Uniform provisions concerning the approval of category L3 vehicles with regard to the installation of lighting and light-signalling devices.
UN R53 — Supplement 7 to the 02 series of amendments
Supplement 6 → 7
- What changed
- The rear-end collision alert signal (RECAS) is a new optional signal, with its own rules in new paragraph 6.17.
- All the fitted direction indicator lamps give the RECAS together, and the RECAS switches ON and OFF automatically.
- The hazard warning signal may now also switch ON automatically to show other road users the risk of imminent danger as defined by Regulations.
- Why
- The proposal aims to enable the RECAS on motorcycles, to warn the driver of the following vehicle to avoid an imminent rear-end collision.
- UN Regulation No. 48 has allowed the RECAS on vehicles of categories M and N since 2011.
- The RECAS activation depends essentially on the following vehicle, so its safety benefits for M and N vehicles can be achieved on motorcycles.
Q1What changed33 changes
Definition of the rear-end collision alert signal (para. 2.22.)
New paragraph 2.22. defines the rear-end collision alert signal (RECAS) as an automatic signal given by the leading vehicle to the following vehicle. The signal warns that the following vehicle needs to take emergency action to avoid a collision.
The RECAS in the device list and the colour list (paras. 5.13. and 5.15.8.)
New paragraph 5.15.8. adds the RECAS to the list of optional lighting and light-signalling devices, with its rules in paragraph 6.17. The colour of the RECAS light must be amber (paragraph 5.13.).
Presence, number, position and tell-tale of the RECAS (paras. 6.17. to 6.17.6. and 6.17.8.)
The RECAS is optional (paragraph 6.17.1.). It must be given by the simultaneous operation of all the fitted direction indicator lamps, as described in paragraph 6.17.7. For number, arrangement, position, geometric visibility and orientation, the RECAS follows paragraphs 6.3.1. to 6.3.5. A tell-tale for the RECAS is optional (paragraph 6.17.8.).
Electrical connections of the RECAS (paras. 6.17.7. to 6.17.7.4.)
The applicant must demonstrate compliance with paragraph 6.17.7. by simulation or other means of verification accepted by the Technical Service responsible for type approval. All the lamps of the RECAS must flash in phase at a frequency of 4.0 +/- 1.0 Hz. If any rear RECAS lamp uses filament light sources, the frequency must be 4.0 +0.0/-1.0 Hz. The RECAS must operate independently of other lamps and must switch ON and OFF automatically. The RECAS must not switch ON if the direction indicator lamps, the hazard warning signal or the emergency stop signal is activated.
When the RECAS may switch ON (paras. 6.17.7.5. and 6.17.7.6.)
The RECAS may switch ON only under the conditions of the table in paragraph 6.17.7.5. At a relative speed (Vr) above 30 km/h, the activation condition is a time to collision (TTC) of 1.4 or less. At a Vr of 30 km/h or less, the activation condition is a TTC of 1.4 / 30 × Vr or less. Vr is the difference in speed between the vehicle with the RECAS and a following vehicle in the same lane. TTC is the estimated time to a collision with a following vehicle, if the relative speed at the time of estimation stays constant. The switch ON period of the RECAS must be not more than 3 seconds (paragraph 6.17.7.6.).
Automatic switching ON of the hazard warning signal (para. 6.9.2.)
The hazard warning signal may now also switch ON automatically to show other road users the risk of imminent danger as defined by Regulations. In this case, the signal must stay ON until it is switched OFF manually or automatically. The heading of paragraph 6.9.2. changes from “Electrical connections” to “Electrical connection”.
Q2Why it changed
- Proposed by
- Experts from the International Motorcycle Manufacturers Association
- Working party
- GRE, 87th session (October 2022)
Reasons
The proposal aims to enable the use of the RECAS on motorcycles. The RECAS is a safety function that warns the driver of the following vehicle to avoid an imminent rear-end collision.
Source
“The objective of this proposal is to enable the use of Rear-End Collision Alert Signal (RECAS) on motorcycles, a safety function aimed at warning the driver of the following vehicle to avoid an imminent rear-end collision”
UN Regulation No. 48 has allowed the installation of the RECAS on vehicles of categories M and N since 2011.
Source
“whose installation is already allowed in UN Regulation No. 48 for vehicles of categories M and N since 2011.”
When the motorcycle detects an imminent collision from the rear, the RECAS gives an automatic signal with the direction indicators. The aim is to prompt the driver behind to take immediate action, to avoid a crash or at least to mitigate its consequences.
Sources (2)
“RECAS provides an automatic signal by means of the direction indicators when the motorcycle detects an imminent collision from the rear”
“to prompt the driver of the vehicle behind the motorcycle to take immediate action with the ultimate goal of avoiding a crash or, at least, mitigating its consequences.”
The RECAS activation does not depend on the vehicle with the system, but essentially on the characteristics of the following vehicle. So the safety benefits of the RECAS for M and N vehicles can be achieved on motorcycles by the same operating principles.
Sources (2)
“as the RECAS activation does not depend on the vehicle equipped with the system, but it is essentially determined by the characteristics of the following vehicle.”
“The safety benefits provided by RECAS for vehicles of categories M and N can be achieved on motorcycles by the same operating principles”
The proposal says that its amendments to UN Regulation No. 53 are equivalent to the existing RECAS provisions in UN Regulation No. 48.
Source
“Therefore, the proposed amendments to UN Regulation No. 53 are equivalent to the existing RECAS provisions in UN Regulation No. 48.”
Document trail
- 2022-07ProposalECE/TRANS/WP.29/GRE/2022/23Proposal by the experts from the International Motorcycle Manufacturers Association for the 87th GRE session
- —Working party adoptsECE/TRANS/WP.29/GRE/87Session report, para. 30: GRE adopted the proposal
- 2022-12Sent to WP.29ECE/TRANS/WP.29/2023/32Text that GRE 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.411.2023.TREATIES-XI.B.16.53UN depositary notification
Q3Who is affected
Vehicle manufacturer
- If you fit a RECAS, make sure all the fitted direction indicator lamps give it together (paragraph 6.17.1.).
- Make sure that the RECAS switches ON only under the Vr and TTC conditions of paragraph 6.17.7.5.
- Make sure that the RECAS switch ON period is not more than 3 seconds (paragraph 6.17.7.6.).
- Make sure the RECAS cannot switch ON while the direction indicators, hazard warning or emergency stop signal is activated.
- Demonstrate compliance with paragraph 6.17.7. by simulation or other means accepted by the Technical Service responsible for type approval.
- If the hazard warning signal switches ON automatically for imminent danger defined by Regulations, keep it ON until switched OFF.
Component supplier
- Check that your direction indicator lamps can flash at the RECAS frequency of 4.0 +/- 1.0 Hz (paragraph 6.17.7.1.).
- If any rear RECAS lamp uses filament light sources, check for a RECAS frequency of 4.0 +0.0/-1.0 Hz (paragraph 6.17.7.1.1.).
Technical service / Approval authority
- Decide whether to accept the applicant's simulation or other verification for the RECAS requirements of paragraph 6.17.7.
- Check that the RECAS meets paragraphs 6.3.1. to 6.3.5. for number, arrangement, position, geometric visibility and orientation.
- Check that the RECAS switch ON conditions follow the Vr and TTC table of paragraph 6.17.7.5.
See every change side by side
RegVault customers compare every version of UN regulations, read the consolidated text and download the PDF.
ⓘ This report gives advice only. It is not legal or type-approval advice.
More UN R53 change reports
- 04 series — Supplement 1
- 04 series — Base text
- 03 series — Supplement 5
- 03 series — Supplement 4
- 03 series — Supplement 3
- 03 series — Supplement 2
- 03 series — Supplement 1
- 03 series — Base text
- 02 series — Supplement 6
- 02 series — Supplement 5
- 02 series — Supplement 4
- 02 series — Supplement 3
- 02 series — Supplement 2