UN R58 Supplement 2 (03 series) · UNECE Regulation No. 58 (ECE R58) — Uniform provisions concerning the approval of: I. Rear underrun protective devices (RUPDs) II. Vehicles with regard to the installation of an RUPD of an approved type III. Vehicles with regard to their rear underrun protection (RUP).
UN R58 — Supplement 2 to the 03 series of amendments
Supplement 1 → 2
- What changed
- New paragraph 3.1.5. says that “Aerodynamic devices and equipment” mean devices that are designed to reduce the aerodynamic drag of road vehicles.
- Paragraphs 16.4. and 25.3. now exclude aerodynamic devices that comply with Annex 8 from the determination of the most rearward point at the rear extremity.
- New Annex 8 (Aerodynamic devices) sets general specifications, test conditions, a test procedure, requirements and marking for these devices.
- Why
- Aerodynamic devices are not defined in the current series of amendments and would have an influence on the position of the Rear Underrun Protection Device.
- The exemption from the geometric positioning of the RUPD implies new requirements for the aerodynamic device itself, defined in a new Annex 8.
- Annex 8 assumes that a device fitted at the rear of the vehicle should not harm occupants in other vehicles during a rear-end collision.
Q1What changed54 changes
Definition of “Aerodynamic devices and equipment” (para. 3.1.5.)
New paragraph 3.1.5. says that “Aerodynamic devices and equipment” mean devices that are designed to reduce the aerodynamic drag of road vehicles.
Aerodynamic devices that comply with Annex 8 left out of the most rearward point
Paragraphs 16.4. and 25.3. now exclude aerodynamic devices that comply with Annex 8 from the determination of the most rearward point at the rear extremity. One existing sentence on non-structural protrusions such as tail lamps now spells “nonstructural” as “non-structural”.
Annex 8: purpose and general specifications
New Annex 8 has the title “Aerodynamic devices”. Its test checks whether the aerodynamic device compromises the rear underrun protection in a collision with the rear of the vehicle or the vehicle combination. Paragraph 2.1. covers the external surface of aerodynamic devices. It must not exhibit, directed outwards, pointed or sharp parts or projections likely to increase the risk or seriousness of bodily injury. Protruding parts of the external surface of an aerodynamic device must not have a radius of curvature less than 2.5 mm, with exceptions (para. 2.3.). Such parts made of a material of hardness not exceeding 60 shore A may have a radius of curvature less than 2.5 mm (para. 2.4.).
Annex 8: test conditions and simulation by calculation
At the request of the manufacturer, the test may be conducted in one of three ways (para. 3.1.). These are a vehicle of the intended type, a representative part of the body of that vehicle type, or a rigid wall. On a vehicle, the test conditions of paragraph 4. apply: for example, the vehicle is at rest on a level, flat, rigid and smooth surface. At the request of the manufacturer, the test procedure of paragraph 5. may be simulated by calculation (para. 3.3.). The mathematical model must be validated by comparison with a physical test, and the manufacturer must draft a validation report. Any change to the mathematical model or to the software likely to invalidate the validation report requires a new validation process.
Annex 8: test procedure and test forces
The aerodynamic device must offer a certain level of deformation to forces applied parallel to the longitudinal axis of the vehicle (para. 5.1.). Alternatively, the device may also be folded or retracted under the influence of force. On a vehicle, body part or rigid wall, the manufacturer defines the height of the centre of the surface or adaptor. Paragraph 5.1.2. sets a horizontal force of maximum 4000 N ± 400 N, applied consecutively to two points. The two points are situated symmetrically about the centre line of the vehicle or the centre line of the device. They are on the rearmost outer edge of the aerodynamic device in completely unfolded or not retracted condition.
Annex 8: requirements for deformation and hardness
Paragraph 6.1. sets a maximum remaining length of 200 mm in longitudinal direction of the vehicle, at the point of application of forces. This applies to the elastic and/or plastic deformation during the application of the test forces as specified in paragraph 5.1.2. The requirement is also deemed to be fulfilled if the device folds or retracts under the test forces to that maximum remaining length. Forces are not applied if the device is made of a material of hardness not exceeding 60 shore A in area 1 of figure 4. Components used to install the device on the body of the vehicle, or mounted on the device, are exempted from these provisions. The hardness measurement is taken with the aerodynamic device as installed on the vehicle.
Annex 8: marking of aerodynamic devices
A clearly legible and indelible marking must be affixed to the aerodynamic device (para. 7.1.). It consists of a serial number, the name of device and the name of manufacturer. It also includes the marking “In accordance to UN Regulation No. 58” and year/month of conformity.
Q2Why it changed
- Proposed by
- Expert from the International Organization of Motor Vehicle Manufacturers
- Working party
- GRSG, 117th session (October 2019)
Reasons
Aerodynamic devices are not defined in the current series of amendments and would have an influence on the position of the Rear Underrun Protection Device. The amendment is proposed to clarify the installation of Rear Underrun Protection Devices with regard to the installation of aerodynamic devices.
Sources (2)
“In the current series of amendments of UN Regulation No. 58 the aerodynamic devices are not defined and would have an influence on the position of the Rear Underrun Protection Device.”
“This amendment for UN Regulation No. 58 is proposed to clarify the installation of Rear Underrun Protection Devices with regard to the installation of aerodynamic devices.”
Paragraphs 16.4. and 25.3. have exemptions for certain components up to 50 mm length. Based on this principle, the proposal exempts aerodynamic devices from the determination of the geometric positioning of the RUPD. This exemption implies new requirements for the aerodynamic device itself, and these are defined in a new Annex 8. Annex 8 assumes that a device fitted at the rear of the vehicle should not harm occupants in other vehicles during a rear-end collision. The main idea is to require a kind of deformation or retraction of the device in an impact that does not compromise RUPD functionality.
Sources (4)
“The paragraphs 16.4. and 25.3. describe the geometric requirements to install a Rear Underrun Protection Device (RUPD) including some special provisions and exemptions for certain components up to 50 mm length.”
“Based on this principle an amendment is proposed to exempt aerodynamic devices from the determination of the geometric positioning of the RUPD. But this exemption implies some new requirements for the aerodynamic device itself.”
“The provisions defined in Annex 8 are based on the assumption that an aerodynamic device fitted at the rear of the vehicle should not harm occupants in other vehicles during a rear-end collision.”
“The main idea is to require a kind of deformation or retraction of the aerodynamic device during an impact that does not compromise the functionality of the RUPD.”
The provisions in paragraph 6.1 of Annex 8 are defined to allow a sufficient deformation or folding functionality under the influence of force. The proposed values relate to discussions for the revision of the 96/53 (EC) to allow “Rear Flaps” on heavy duty vehicles. A request by railway operators was mentioned. The request is a maximum of 200 mm in longitudinal direction of the vehicle in folded position, for intermodal transport of trailers on wagons.
Sources (3)
“The provisions in paragraph 6.1 of Annex 8 are defined to allow a sufficient deformation or folding functionality under the influence of force.”
“The proposed values relate to discussions for the revision of the 96/53 (EC) to allow “Rear Flaps” on heavy duty vehicles.”
“There was mentioned a request by railway operators that for the transport of trailers on the wagon (intermodal traffic) the aerodynamic devises shall have maximum 200 mm in longitudinal direction of the vehicle in folded position.”
The provisions in paragraph 5.1.2. of Annex 8 are defined to allow a sufficient stability of aerodynamic devices. They are also defined to guarantee a level of forces that is applicable to deform, unfold or retract the aerodynamic device. The force of 4.000 N is based on an assumption about a passenger car in a rear end collision. The assumption is that the passenger car touches the RUPD before parts of the aerodynamic devices partly touch other parts of the vehicle body.
Sources (4)
“The provisions in paragraph 5.1.2. of Annex 8 are defined to allow on the one hand a sufficient stability of aerodynamic devices”
“on the other hand to guarantee a level of forces that is applicable to deform/unfold/retract the aerodynamic device.”
“The force of 4.000 N base on the assumption that the passenger car in a rear end collision is in contact with the rear underrun protection device (RUPD)”
“before parts of the aerodynamic devices are partly in contact with other parts of the vehicle body over impact time”
Proposer's reason (informal document GRSG-117-51)
The definition in paragraph 3.1.5. is taken from the ACT post TCMV 4 July 2019. That text also reflects other equipment and front devices. UN R58 only reflects on rear devices, so the definition should be adjusted.
Submitted by Expert from OICA. Working party adoption: ECE/TRANS/WP.29/GRSG/96, para. 41.
Sources (2)
“This definition is taken from the ACT post TCMV 4 July 2019.”
“The AC post TCMV reflects also other equipment and on front devices. UN R58 only reflects on rear devices. Therefore the definition should be adjusted.”
Document trail
- 2019-07ProposalECE/TRANS/WP.29/GRSG/2019/32Official proposal by the expert from the International Organization of Motor Vehicle Manufacturers to introduce the aerodynamic device in UN Regulation No. 58
- —Amended in sessionGRSG-117-51Proposal for amendments to GRSG-117-50, based on ECE/TRANS/WP.29/GRSG/2019/32, with a new paragraph 3.1.5. definition, by the expert from OICA
- —Working party adoptsECE/TRANS/WP.29/GRSG/96Session report, para. 41: GRSG adopted ECE/TRANS/WP.29/GRSG/2019/32 as amended by GRSG-117-51
- 2019-12Sent to WP.29ECE/TRANS/WP.29/2020/19Proposal for Supplement 1 to the 03 series of amendments that GRSG sent to WP.29 and AC.1; WP.29 amended the title to read Supplement 2 (ECE/TRANS/WP.29/1151, para. 88)
- 2020-03WP.29 adoptsECE/TRANS/WP.29/1151Adopted at the 180th session (session report, para. 126)
- 2020-09-25In forceC.N.481.2020.TREATIES-XI.B.16.58UN depositary notification
Q3Who is affected
Vehicle manufacturer
- Check that aerodynamic devices comply with the provisions in Annex 8 before you exclude them from the most rearward point.
- If you request simulation by calculation (Annex 8, para. 3.3.), draft a validation report for the mathematical model.
- Specify the exact location of the centre of the surface or adaptor in the area of application of forces.
Component supplier
- Make sure each aerodynamic device carries a clearly legible and indelible marking as listed in Annex 8, paragraph 7.1.
Technical service / Approval authority
- Check that aerodynamic devices excluded from the most rearward point comply with the provisions in Annex 8.
- Check the 200 mm maximum remaining length in longitudinal direction of the vehicle under the paragraph 5.1.2 test forces.
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ⓘ This report gives advice only. It is not legal or type-approval advice.