UN-R58/03 (Rev.3)

8 Aerodynamic devices

Any vehicle of category G will be deemed to satisfy the condition for the ground clearance set out in this Regulation, if the departure angle (ISO 612:1978) does not exceed:
(a)    10° for vehicles of categories M1G and N1G;
(b)    20° for vehicles of categories M2G and N2G; and
(c)    25° for vehicles of categories M3G and N3G;
over a width which is not shorter than that of the rear axle by more than 100 mm on either side (excluding any bulging of the tyres close to the ground).
Where there is more than one rear axle, the width to be considered is that of the widest. The requirements of subparagraphs (a) to (c) of this paragraph shall be satisfied at least on a line:
(a)    At a distance of not more than 450 mm from the rear extremity of the vehicle;
(b)    That may have interruptions summing up in not more than 200 mm

"Unladen mass" means the mass of the vehicle in running order, unoccupied and unladen but complete with fuel, coolant, lubricant, tools and a spare wheel (if provided as standard equipment by the vehicle manufacturer);

“Aerodynamic devices and equipment” mean devices that are designed to reduce the aerodynamic drag of road vehicles.

Notice of approval, or of extension or of refusal of approval of a type of RUPD pursuant to this Regulation shall be communicated to the Parties to the 1958 Agreement which apply this Regulation, by means of a form conforming to the model in Annex 1 to this Regulation.

The cross-member shall have a section height of at least 120 mm. The lateral extremities of the cross member shall not bend to the rear or have a sharp outer edge; this condition is fulfilled when the lateral extremities of the cross-member are rounded on the outside and have a radius of curvature of not less than 2.5 mm.

The RUPD shall offer adequate resistance to forces applied parallel to the longitudinal axis of the vehicle. (This shall be demonstrated in accordance with the test procedure and test conditions specified in Annex 5 to this Regulation.) The maximum horizontal deflection of the RUPD observed during and after the application of the test forces specified in Annex 5 shall be recorded on the type approval communication (Annex 1, item 8).

The maximum lateral clearance measured between the elements of the underrun device and the elements of the platform lift, which move through the interruption when the lift is operated and which make the interruption necessary, may amount to no more than 2.5 cm.

Every rear underrun protective device approved under this Regulation shall be so manufactured as to conform to the type approved by meeting the requirements set out in paragraph 7. above.

If the holder of the approval completely ceases to manufacture a type of rear underrun protective device approved in accordance with this Regulation, he shall so inform the Type Approval Authority which granted the approval. Upon receiving the relevant communication that Authority shall inform thereof the other Parties to the 1958 Agreement applying this Regulation by means of a communication form conforming to the model in Annex 1 to this Regulation.

Drawings of the vehicle showing, according to the criteria referred to in paragraph 13.1.2. of this Regulation, the vehicle type in side and rear elevation with the indication of the position of the approved RUPD(s) and design details of its (their) fixing elements to the chassis of the vehicle;

An approval number shall be assigned to each type approved. Its first two digits (at present 03 corresponding to the 03 series of amendments) shall indicate the series of amendments incorporating the most recent major technical amendments made to the Regulation at the time of issue of the approval. The same Contracting Party may not assign the same number to another vehicle type.

(a) 450 mm for motor vehicles and trailers with hydropneumatic, hydraulic or pneumatic suspension or a device for automatic levelling according to load. In any case, a departure angle up to 8° according to ISO 612:1978 with a maximum ground clearance of 550 mm shall be deemed to satisfy the requirements.

(b) 500 mm [DEL] for vehicles other than those in (a) above. In any case, a departure angle up to 8° according to ISO 612:1978 with a maximum ground clearance of 550 mm shall be deemed to satisfy the requirements

For vehicles of categories M, N₁, N₂ with a maximum mass not exceeding 8 t, O₁ and O₂, the ground clearance with respect to the underside of the protective device, even when the vehicle is unladen, shall not exceed 550 mm over its entire width and shall be such that the height above the ground of the points of application of the test forces applied to the device according to Part I of this Regulation and recorded in the type approval communication form (Annex 1, item 7) does not exceed 600 mm.

The width of the rear protective device shall at no point exceed the width of the rear axle measured at the outermost points of the wheels, excluding the bulging of the tyres close to the ground, nor shall RUPD be more than 100 mm shorter on either side. Where the device is contained in or comprises the vehicle bodywork which itself extends beyond the width of the rear axle, the requirement, that the width of the RUPD shall not exceed that of the rear axle, shall not apply. However, in case of vehicles of categories O₁ and O₂ where the tyres project for more than half of their width outside the bodywork (excluding the wheel guards) or outside the chassis in the absence of bodywork, the width of the RUPD shall not be less than 100 mm deducted from the distance measured between the innermost points of the tyres, excluding the bulging of the tyres close to the ground, on either side. Where there is more than one rear axle, the width to be considered is that of the widest rear axle. In addition the requirements of paragraphs 3.1.2. and 3.1.3. of Annex 5 relating the distance of the points of application of the test forces from the outer edges of the rear wheels (Annex 1, item 7) shall be verified and recorded in the type approval communication form.

For vehicles of categories M, N1, N2 with a maximum mass not exceeding 8 t, O1 and O2, the device shall be so fitted that the horizontal distance between the rear of the cross-member of the device and the most rearward point at the rear extremity of the vehicle, including any platform lift system or access ramp(s), does not exceed 400 mm diminished by the largest total deformation including both plastic and elastic deformation (paragraph 7.3. of Part I) measured and recorded during the test at any of the points where the test forces are applied (Annex 1, item 8) during the type approval of the rear underrun protective device in conformity with the provisions of Part I of this Regulation and recorded in the type approval communication form. In measuring this distance, any part of the vehicle which is more than 2 m above the ground for every loading condition of the vehicle shall be excluded.

For vehicles of categories N2 with a maximum mass exceeding 8 t, N3, and vehicles of categories O3 and O4, equipped with a platform lift or access ramp(s) or being designed as a tipping trailer, the same requirement as above applies; however, for vehicles of these categories, the horizontal distance shall not exceed 300 mm measured to the rear of the cross-member before the test forces are applied.

For vehicles of categories O3 and O4, without any platform lift system or access ramp(s) and not being designed as a tipping-trailer, the maximum horizontal distances are reduced to 200 mm before the test forces have been applied and 300 mm diminished by the largest total deformation including both plastic and elastic deformation (paragraph 7.3. of Part I) measured and recorded during the test at any of the points where the test forces are applied (Annex 1, item 8).

In any case non-structural protrusions such as tail lamps and those of less than 50 mm of size in any direction, such as rubber bumpers, resilient buffers, hinges and latches shall be excluded from the determination of the most rearward point at the rear extremity. 

In any case aerodynamic devices that comply with the provisions in annex 8 shall be excluded from the determination of the most rearward point at the rear extremity.

Before the application of the test forces, the maximum allowed horizontal distance of a single, a segmented or an inclined cross-member of a RUPD is 100 mm between the rear of the cross-member measured at the most forward point and the rear of the cross-member measured at the most rearward point, measured in the longitudinal plane of the vehicle.

The device shall be so fitted that after the application of the test forces specified in Annex 5 for vehicles of the categories N2 with a maximum mass exceeding 8 t, N3, O₃ and O₄, the maximum ground clearance of the protective device, even when the vehicle is unladen, shall at any point not exceed by more than 60 mm the value before test. For vehicles with a departure angle up to 8° (paragraph 16.1.) the maximum ground clearance shall not exceed 600 mm.

The Type Approval Authority issuing the extension of approval shall assign a series number for such an extension and inform thereof the other Parties to the 1958 Agreement applying this Regulation by means of a communication form conforming to the model in Annex 2 to this Regulation.

An approval number shall be assigned to each type approved. Its first two digits (at present 03 corresponding to the 03 series of amendments) shall indicate the series of amendments incorporating the most recent major technical amendments made to the Regulation at the time of issue of the approval. The same Contracting Party may not assign the same number to another vehicle type.

Notice of approval or of extension or of refusal of approval of a vehicle type pursuant to this Regulation shall be communicated to the Parties to the 1958 Agreement which apply this Regulation, by means of a form conforming to the model in Annex 3 to this Regulation.

(a) 450 mm for motor vehicles and trailers with hydropneumatic, hydraulic or pneumatic suspension or a device for automatic levelling according to load. In any case a departure angle up to 8° according to ISO 612:1978 with a maximum ground clearance of 550 mm shall be deemed to satisfy the requirements.

(b) 500 mm [DEL] for vehicles other than those in (a) above. In any case a departure angle up to 8° according to ISO 612:1978 with a maximum ground clearance of 550 mm shall be deemed to satisfy the requirements

For vehicles of categories M, N1, N2 with a maximum mass not exceeding 8 t, O1 and O2, the RUPD shall be situated as close to the rear of the vehicle as possible. The maximum horizontal distance between the rear of the device and the most rearward point at the rear extremity of the vehicle, including any platform lift system or access ramp(s), does not exceed 400 mm measured to the rear of the cross-member and recorded during the test when the test forces are applied.

For vehicles of categories N2 with a maximum mass exceeding 8 t, N3, and vehicles of categories O3 and O4, equipped with a platform lift or access ramp(s) or being designed as a tipping trailer, the same requirement as above applies; however, for vehicles of these categories, the horizontal distance shall not exceed 300 mm measured to the rear of the cross-member before the test forces are applied.

For RUP for vehicles of categories O3 and O4, without any platform lift system or access ramp(s) and not being designed as a tipping-trailer, the maximum horizontal distance is reduced to 200 mm before and 300 mm during the test when the test forces are applied.

In any case non-structural protrusions such as tail lamps and those of less than 50 mm of size in any direction, such as rubber bumpers, resilient buffers, hinges and latches shall be excluded from the determination of the most rearward point at the rear extremity.

In any case aerodynamic devices that comply with the provisions in Annex 8 shall be excluded from the determination of the most rearward point at the rear extremity. 

Before the application of the test forces the maximum allowed horizontal distance of a single, a segmented or an inclined cross-member of a RUPD is 100 mm between the rear of the cross-member measured at the most forward point and the rear of the cross-member measured at the most rearward point, measured in the longitudinal plane of the vehicle.

The width of the RUP shall at no point exceed the width of the rear axle measured at the outermost points of the wheels, excluding the bulging of the tyres close to the ground, nor shall RUP be more than 100 mm shorter on either side. Where the device is contained in or comprises the vehicle bodywork which itself extends beyond the width of the rear axle, the requirement, that the width of the RUP shall not exceed that of the rear axle, shall not apply. However, in case of vehicles of categories O1 and O2 where the tyres project for more than half of their width outside the bodywork (excluding the wheel guards) or outside the chassis in the absence of bodywork, the width of the RUP shall not be less than 100 mm deducted from the distance measured between the innermost points of the tyres, excluding the bulging of the tyres close to the ground, on either side. Where there is more than one rear axle, the width to be considered is that of the widest rear axle. In addition, the requirements of paragraphs 3.1.2. and 3.1.3. of Annex 5 relating the distance of the points of application of the test forces from the outer edges of the rear wheels (Annex 1, item 7) shall be verified and recorded in the type approval communication form.

The cross-member shall have a section height of at least 120 mm. The lateral extremities of the cross-member shall not bend to the rear or have a sharp outer edge, this condition is fulfilled when the lateral extremities of the RUP are rounded on the outside and have a radius of curvature of not less than 2.5 mm.

After applying the test forces specified in Annex 5 for vehicles of the categories N₂ with a maximum mass exceeding 8 t, N₃, O₃ and O₄, the maximum ground clearance of the protective device, even when the vehicle is unladen, shall at any point not exceed by more than 60 mm the value before test. For vehicles with a departure angle up to 8° (paragraph 16.1.) the maximum ground clearance shall not exceed 600 mm.

The maximum lateral clearance measured between the elements of the underrun device and the elements of the platform lift, which move through the interruption when the lift is operated and which make the interruption necessary, may amount to no more than 2.5cm.

The individual elements of the underrun protection, including those outboard of the lift system, where provided, shall have an effective surface area, in each case, of at least 420 cm².

Every vehicle approved under this Regulation shall be so manufactured as to conform to the type approved by meeting the requirements set out in paragraph 25. above.

The Type Approval Authority issuing the extension of approval shall assign a series number for such an extension and inform thereof the other Parties to the 1958 Agreement applying this Regulation by means of a communication form conforming to the model in Annex 3 to this Regulation.

Characteristics of the chassis to which the device may be installed (e.g. stiffness, profile dimensions, ..) (if applicable)

The vehicle may, if necessary to achieve the test forces required in paragraph 3.1. below, be restrained by any method, this method to be specified by the vehicle manufacturer.

The requirements of paragraphs 7.3. and 25.7. of this Regulation shall be verified by means of suitable test mandrels; the forces for tests prescribed in paragraphs 3.1.1. and 3.1.2. below shall be applied separately and consecutively, via a surface not more than 250 mm in height (but covering the maximum section height of the cross-member or RUP, the exact height shall be indicated by the manufacturer) and 200 mm wide, with a radius of curvature of 5 ± 1 mm at the vertical edges. The RUP shall offer adequate resistance to forces applied parallel to the longitudinal axis of the vehicle. The surface shall not be rigidly fixed to the RUPD or to the RUP and shall be articulated in all directions. The height above the ground of the centre of the surface shall be defined by the manufacturer within the lines that bound the device horizontally. When the test is carried out on a vehicle the height shall not, however, exceed the height as specified in paragraphs 16.1. and 16.2. or as specified in paragraphs 25.1. and 25.2. of this Regulation when the vehicle is unladen. The order in which the forces are applied may be specified by the manufacturer.

In the cases defined in paragraphs 1.1.1. and 1.1.2. of this annex a horizontal force of 100 kN or 50 per cent of the force generated by the maximum mass of the vehicle, whichever is the lesser, shall be applied consecutively to two points located 300 ± 25 mm from the longitudinal planes tangential to the outer edges of the wheels on the rear axle or of the RUPD, if it exceeds the width of the rear axle, and to a third point located on the line joining these two points, in the median vertical plane of the vehicle.

If any point defined under paragraph 3.1. is located within the interruption area of the underrun protection device as mentioned in paragraph 7.4. or 25.8. of this Regulation, the test forces shall be applied at replacement points located:

for the requirement under paragraph 3.1.1., on the horizontal centerline and within 50 mm of each vertical edge closest to the intended points of force application, as defined in that paragraph, and

for the requirement under paragraph 3.1.2., at the intersection of the horizontal and vertical centerlines of each element furthest from the vertical centerline of the device or of the vehicle, whichever is applicable. These points should be a maximum of 325 mm from the longitudinal planes tangential to the outer edges of the wheels on the rear axle.

Requirements for different vehicle categories

Annex 8

Aerodynamic devices

Purpose

The purpose of this test is to verify whether the aerodynamic device in the event of a collision with the rear of the vehicle or the vehicle combination is compromising the rear underrun protection.

General specifications

The external surface of aerodynamic devices shall not exhibit, directed outwards, any pointed or sharp parts or any projections of such shape, dimensions, direction or hardness as to be likely to increase the risk or seriousness of bodily injury to a person hit by the external surface or brushing against it in the event of a collision.

The external surface of vehicles shall not exhibit, directed outwards, any part likely to catch on pedestrians, cyclists or motor cyclists.

Protruding parts of the external surface of an aerodynamic device shall not have a radius of curvature less than 2.5 mm. Those parts of the external surface of an aerodynamic device which are so located that, in their folded or retracted condition as well as when in operation, they cannot be contacted by a sphere 100 mm in diameter, may have a radius of curvature less than 2.5 mm. This requirement shall not apply to parts of the external surface which protrude less than 5 mm, but the outward facing angles of such parts shall be blunted, save where such parts protrude less than 1.5 mm.

Protruding parts of the external surface, made of a material of hardness not exceeding 60 shore A, may have a radius of curvature less than 2.5 mm. The hardness measurement shall be taken with the component as installed on the vehicle. Where it is impossible to carry out a hardness measurement by the Shore A procedure, comparable measurements shall be used for evaluation.

Test conditions for aerodynamic devices

At the request of the manufacturer the test may be conducted either:

On a vehicle of the type for which an aerodynamic device is intended; in this case the test conditions set out in paragraph 4. below shall be observed; or 

On a part of the body of the vehicle type for which the aerodynamic device is intended; this part shall be representative of the vehicle type(s) in question; or

On a rigid wall. 

In the case of paragraph 3.1.2. and 3.1.3., the parts used to connect the aerodynamic devices to a part of the vehicle body or to a rigid wall shall be equivalent to those which are used to secure the aerodynamic devices when it is installed on the vehicle. Every device shall be accompanied by installation and operating instructions giving sufficient information for any competent person to install it correctly.

At the request of the manufacturer the test procedure described in paragraph 5. may be simulated by calculation.
    The mathematical model shall be validated in comparison with the actual test conditions. To that effect, a physical test shall be conducted for the purposes of comparing the results obtained when using the mathematical model with the results of a physical test. Comparability of the test results shall be proven. A validation report shall be drafted by the manufacturer.
    Any change made to the mathematical model or to the software likely to invalidate the validation report shall require a new validation process to be conducted

Test conditions for vehicles

The vehicle shall be at rest on a level, flat, rigid and smooth surface.

The front wheels shall be in the straight-ahead position.

The tyres shall be inflated to the pressure recommended by the vehicle manufacturer.

The vehicle is unladen. 

The vehicle may, if necessary to achieve the test force required in paragraph 5.1.2. below, be restrained by any method. This method is to be specified by the vehicle manufacturer.

Vehicles equipped with hydropneumatic, hydraulic or pneumatic suspension or a device for automatic levelling according to load shall be tested with the suspension or device in the normal running condition specified by the manufacturer.

Test procedure

The aerodynamic device shall offer a certain level of deformation to forces applied parallel to the longitudinal axis of the vehicle. Alternatively, the device may also be folded or retracted under the influence of force. The test shall be verified by means of suitable test mandrels. The device used to distribute the test force over the stated flat surface shall be connected to the force actuator through a swivel joint. In cases of geometric incompatibilities, it is recommended to use an adaptor instead of a device with a flat surface.

A force shall be applied parallel to the longitudinal axis of the vehicle via a surface not more than 250 mm in height and 200 mm wide with a radius of curvature of 5 ± 1 mm at the vertical edges or an adaptor. The surface or adaptor shall not be rigidly fixed to the aerodynamic device and shall be articulated in all directions. When the test is carried out on a vehicle the height of the centre of the surface or adaptor shall be defined by the manufacturer in an area between the lowest edge of the aerodynamic device and a point no more than 2.0 meters above the ground in vehicle-mounted condition (see figure 1). This point is to be defined on a laden vehicle with the technically permissible maximum laden mass. 
    When the test is carried out on a part of the body of the vehicle type or on a rigid wall the height of the centre of the surface or adaptor shall be defined by the manufacturer in an area between the lowest edge of the aerodynamic device and the point that represents the height of no more than 2.0 meters above the ground in vehicle-mounted condition on a laden vehicle with the technically permissible maximum laden mass (see figure 2). 
    The exact location of the centre of the surface or adaptor in the area of application of forces shall be specified by the manufacturer. In cases there the aerodynamic device has different stiffness’s in the area of application of forces (e.g. due to reinforcements, different materials or thicknesses etc.) the location of centre of the surface or adaptor is to be defined in the area with the highest resistance against external forces in longitudinal direction of the vehicle.

Figure 1

Figure 2

A horizontal force of maximum 4000 N ± 400 N shall be applied consecutively to two points situated symmetrically about the centre line of the vehicle or the centre line of the device on the rearmost outer edge of the aerodynamic device in completely unfolded or not retracted condition (see figure 3). The order in which the forces are applied may be specified by the manufacturer.

Figure 3

Requirements

The aerodynamic device shall be so fitted that during the application of the test forces as specified in paragraph 5.1.2 this aerodynamic device has at the point of application of forces an elastic and/or plastic deformation with a maximum remaining length of 200 mm in longitudinal direction of the vehicle.
This requirement is also deemed to be fulfilled if the aerodynamic device will be folded or retracted under influence of test forces as specified in paragraph 5.1.2 so that the aerodynamic device has in this folded or retracted position a maximum remaining length of 200 mm in longitudinal direction of the vehicle.

Notwithstanding the provisions in paragraph 5.1., 5.1.1., 5.1.2. and 6.1. the application of forces shall not be conducted if the aerodynamic device is made of a material of hardness not exceeding 60 shore A in the area 1 regarding figure 4. Components (fastenings, hinges, actuators, springs, cables, lamps, etc.) used to install the aerodynamic device on the body of the vehicle or that are mounted on the aerodynamic device are exempted from these provisions.
The hardness measurement shall be taken with the aerodynamic device as installed on the vehicle. Where it is impossible to carry out a hardness measurement by the Shore A procedure, comparable measurements shall be used for evaluation

Figure 4

Marking

There shall be affixed to the aerodynamic device a clearly legible and indelible marking consisting of:
(a)    A serial number;
(b)    Name of device;
(c)    Name of manufacturer;
(d)    The marking "In accordance to UN Regulation No. 58” and year/month of conformity (e.g. 2018/01).