Commission Delegated Regulation (EU) 2015/68Show full title

5. Special provisions concerning tractors U.K.

5.1. Energy consumption U.K.

Tractors equipped with anti-lock braking systems shall maintain their performance when the service braking control device is fully applied for long periods. Compliance with the requirement shall be verified by means of the procedure referred to in points 5.1.1, 5.2.3, 5.2.4, 5.2.5, 5.3, 6.1.1, 6.1.3, 6.1.4, 6.3:

5.1.1. Test procedure U.K.

5.1.1.1. The initial energy level in the energy storage device(s) shall be that specified by the manufacturer. This level shall be at least such as to ensure the efficiency prescribed for service braking when the vehicle is laden. The energy storage device(s) for pneumatic auxiliary equipment shall be isolated. U.K.

5.1.1.2. From an initial speed of not less than 50 km/h (or v_max, whichever is lower), on a surface with a coefficient of adhesion of 0,3 or less, the brakes of the laden vehicle shall be fully applied for a time t, during which time the energy consumed by the indirectly controlled wheels shall be taken into consideration and all directly controlled wheels shall remain under control of the anti-lock braking system throughout that time. U.K.

Until such test surfaces become generally available, tyres at the limit of wear, and higher values up to 0,4 may be used at the discretion of the technical service. The actual value obtained and the type of tyres and surface shall be recorded.

5.1.1.3. The vehicle's engine shall be then stopped or the supply to the energy storage device(s) cut off. U.K.

5.1.1.4. The service braking control device shall be then fully actuated four times in succession with the vehicle stationary. U.K.

5.1.1.5. When the control device is applied for the fifth time, it shall be possible to brake the vehicle with at least the performance prescribed for secondary braking of the laden vehicle. U.K.

5.1.1.6. During the tests, in the case of a vehicle authorised to tow a vehicle equipped with a compressed-air braking system, the supply line shall be blocked off and an energy storage device of 0,5 litre capacity shall be connected to the control line (in accordance with point 1.2.2.3 of Annex IV, section A). When the brakes are applied for the fifth time, as provided in point 5.1.1.5 of this Annex, the energy level supplied to the control line shall not be below half the level obtained at a full application starting with the initial energy level. U.K.

5.1.2. Additional requirements U.K.

5.1.2.1. The coefficient of adhesion of the road surface is measured with the vehicle in question, by the method described in point 1.1 of Appendix 2. U.K.

5.1.2.2. The braking test shall be conducted with the engine disconnected and idling, and with the vehicle laden. U.K.

5.1.2.3. The braking time t shall be 15 seconds. U.K.

5.1.2.4. If the time t cannot be completed in a single braking phase, further phases may be used, up to a maximum of four in all. U.K.

5.1.2.5. If the test is conducted in several phases, no fresh energy shall be supplied between the phases of the test. From the second phase, the energy consumption corresponding to the initial brake application may be taken into account, by subtracting one full brake application from the four full applications prescribed in points 5.1.1.4, 5.1.1.5, 5.1.1.6 and 5.1.2.6 for each of the second, third and fourth phases used in the test procedure prescribed in point 5.1.1 as applicable. U.K.

5.1.2.6. The performance prescribed in point 5.1.1.5 shall be deemed to be satisfied if, at the end of the fourth application, with the vehicle stationary, the energy level in the storage device(s) is at or above that required for secondary braking with the laden vehicle. U.K.

5.2. Utilisation of adhesion U.K.

5.2.1. The utilisation of adhesion by the anti-lock braking system takes into account the actual increase in braking distance beyond the theoretical minimum. The anti-lock braking system shall be deemed to be satisfactory when the condition U.K.

ε ≥ 0,75

is satisfied, where ε represents the adhesion utilised, as described in point 1.2 of Appendix 2.

5.2.2. The adhesion utilisation (ε) shall be measured on road surfaces with a coefficient of adhesion of 0,3 or less, and of about 0,8 (dry road), with an initial speed of 50 km/h or v_max, whichever is the lower. To eliminate the effects of differential brake temperatures it is recommended that z_AL (see Appendix 1) be determined prior to the determination of k. U.K.

Until such test surfaces become generally available, tyres at the limit of wear, and higher values up to 0,4 may be used at the discretion of the technical service. The actual value obtained and the type of tyres and surface shall be recorded.

5.2.3. The test procedure to determine the coefficient of adhesion (k) and the formulae for calculation of the adhesion utilisation (ε) shall be those laid down in Appendix 2. U.K.

5.2.4. The utilisation of adhesion by the anti-lock braking system shall be checked on complete vehicles equipped with anti-lock braking systems of categories 1 or 2. In the case of vehicles equipped with category 3 anti-lock braking systems, only the axle(s) with at least one directly controlled wheel shall satisfy this requirement. U.K.

5.2.5. The condition ε ≥ 0,75 shall be checked with the vehicle laden and unladen. The laden test on the high-adhesion surface may be omitted if the prescribed force on the control device does not achieve full cycling of the anti-lock braking system. For the unladen test, the control force may be increased up to 1 000 N if no cycling is achieved with its full force value. A higher force value than the one of the full force may be used if required to activate the anti-lock braking system. If 1 000 N is insufficient to make the system cycle, then this test may be omitted. For air braking systems, the air pressure may not be increased above the cut-out pressure for the purpose of this test. U.K.

5.3. Additional checks U.K.

The following additional checks shall be carried out with the engine disconnected, with the vehicle laden and unladen:

5.3.1.

The wheels directly controlled by an anti-lock braking system shall not lock when the full force is suddenly applied on the control device, on the road surfaces specified in point 5.2.2, at an initial speed of 40 km/h and at a high initial speed as indicated in the table below:

Condition	Maximum test speed
High adhesion surface	0,8 vmax ≤ 80 km/h
Low adhesion surface	0,8 vmax ≤ 70 km/h

5.3.2.

When an axle passes from a high-adhesion surface (k_H) to low-adhesion surface (k_L) where k_H ≥ 0,5 and k_H/k_L ≥ 2, with the full force applied on the control device, the directly controlled wheels shall not lock. The running speed and the instant of applying the brakes shall be so calculated that, with the anti-lock braking system fully cycling on the high-adhesion surface, the passage from one surface to the other is made at high and at low speed, under the conditions laid down in point 5.3.1 above.

5.3.3.

When a vehicle passes from a low-adhesion surface (k_L) to a high-adhesion surface (k_H) where k_H ≥ 0,5 and k_H/k_L ≥ 2, with the full force applied on the control device, the deceleration of the vehicle shall rise to the appropriate high value within a reasonable time and the vehicle shall not deviate from its initial course. The running speed and the instant of applying the brakes shall be so calculated that, with the anti-lock braking system fully cycling on the low-adhesion surface, the passage from one surface to the other occurs at approximately 50 km/h or 0,8 v_max, whichever is the lower.

5.3.4.

In the case of vehicles equipped with anti-lock braking systems of categories 1 and 2, when the right and left wheels of the vehicle are situated on surfaces with differing coefficients of adhesion (k_H and k_L) where k_H ≥ 0,5 and k_H/k_L ≥ 2 the directly controlled wheels shall not lock when the full force is suddenly applied on the control device at a speed of 50 km/h or 0,8 v_max, whichever is the lower.

5.3.5.

Furthermore, laden vehicles equipped with anti-lock braking systems of category 1 shall, under the conditions of point 5.3.4, satisfy the braking rate prescribed in Appendix 3.

5.3.6.

However, in the tests provided for in points 5.3.1, 5.3.2, 5.3.3, 5.3.4 and 5.3.5, brief periods of wheel-locking are allowed. Furthermore, wheel-locking is permitted when the vehicle speed is less than 15 km/h; likewise, locking of indirectly controlled wheels is permitted at any speed, but stability and steerability shall not be affected.

5.3.7.

During the tests provided for in points 5.3.4 and 5.3.5, steering correction is permitted if the angular rotation of the steering control device is within 120° during the initial 2 seconds and not more than 240° in all. Furthermore, at the beginning of these tests the longitudinal median plane of the vehicle shall pass over the boundary between the high- and low-adhesion surfaces and during these tests no part of the (outer) tyres shall cross this boundary.

5.3.8.

The following notes are taken into account:

5.3.8.1.

k_H and k_L are measured as laid down in Appendix 2 to this Annex.

5.3.8.2.

The purpose of the tests in the following points 5.3.1, 5.3.2, 5.3.3 and 5.3.4 is to check that the directly controlled wheels do not lock and that the vehicle remains stable. In these tests a higher force value than the one of the full force may be used if required to activate the anti-lock braking system.

5.3.8.3.

With regard to points 5.3.1 and 5.3.2 it is not necessary, therefore, to make complete stops and bring the vehicle to a complete halt on the low-adhesion surface.