ANNEX IISupplementary provisions
ANNEX II Requirements applying to testing and performance of braking systems and trailer braking couplings and of vehicles fitted with them 1. Definitions For the purposes of this Annex: 1.1. ‘axle group’ means multiple axles where the axle spread between one axle and its adjacent axle is equal to or less than 2,0 m. Where the axle spread between one axle and its adjacent axle is greater than 2,0 m, each individual axle shall be considered as an independent axle group. 1.2. ‘adhesion utilisation curves’ of a vehicle means curves showing, for specified load conditions, the adhesion utilised by each axle i plotted against the braking rate of the vehicle. 2. Braking tests 2.1. General The maximum design speed is considered, throughout this Annex, to be in the forward direction of the vehicle travel, unless otherwise explicitly mentioned. 2.1.1. The performance prescribed for braking systems shall be based on the stopping distance and the mean fully developed deceleration or only on one of those two quantities. The performance of a braking system shall be determined by measuring the stopping distance in relation to the initial speed of the vehicle and by measuring the mean fully developed deceleration during the test or only on one of those two quantities. Both stopping distance and mean fully developed deceleration or only one of them shall be prescribed and measured, following to the test to be performed. 2.1.2. The stopping distance shall be the distance covered by the vehicle from the moment when the driver begins to actuate the control device of the braking system until the moment when the vehicle stops; the initial vehicle speed (v 1 ) shall be the speed at the moment when the driver begins to actuate the control device of the braking system; the initial speed shall not be less than 98 % of the prescribed speed for the test in question. The mean fully developed deceleration d m shall be calculated as the deceleration averaged with respect to distance over the interval v b to v e according to the following formula: Where: v 1 = initial vehicle speed calculated as described in the first subparagraph v b = vehicle speed at 0,8 v 1 in km/h v e = vehicle speed at 0,1 v 1 in km/h s b = distance travelled between v 1 and v b in metres s e = distance travelled between v 1 and v e in metres The speed and distance shall be determined using instrumentation having an accuracy of ± 1 % at the prescribed speed for the test. The d m may be determined by other methods than the measurement of speed and distance; in this case, the accuracy of the d m shall be within ± 3 %. 2.1.3. For the type-approval of any vehicle, the braking performance shall be measured during road tests conducted in the following conditions: 2.1.3.1. The vehicle's condition as regards mass shall be as prescribed for each type of test and be specified in the test report. 2.1.3.2. The test shall be carried out at the speeds prescribed for each type of test; if the maximum design speed of a vehicle is lower than the speed prescribed for a test, the test shall be performed at the vehicle's maximum design speed. 2.1.3.3. During the tests, the force applied to the control device of the braking system in order to obtain the prescribed performance shall not exceed 600 N on the foot or 400 N on the hand operated control devices. 2.1.3.4. The road shall have a surface affording good adhesion, unless specified otherwise. 2.1.3.5. The tests shall be performed when there is no wind liable to affect the results. 2.1.3.6. At the start of the tests the tyres shall be cold and at the pressure prescribed for the load actually borne by the wheels when the vehicle is stationary. 2.1.3.7. The prescribed performance shall be obtained without deviation of the vehicle from its course, without abnormal vibrations and without wheel-locking. Wheel-locking is permitted where specifically mentioned. 2.1.4. Behaviour of the vehicle during braking 2.1.4.1. In braking tests, and in particular in those at high speed, the general behaviour of the vehicle during braking shall be checked. 2.1.4.2. Behaviour of the vehicle during braking on a road on which adhesion is reduced. The behaviour of vehicles of categories Tb, R2b, R3b, R4b and S2b on a road on which adhesion is reduced, shall meet the relevant requirements of Appendix 1 and, if the vehicle is equipped with ABS, of Annex XI too. 2.2. Type-0 braking test (ordinary performance test with brakes cold) 2.2.1. General 2.2.1.1. The brake shall be cold. A brake is deemed to be cold when one of the following conditions is met: 2.2.1.1.1. The temperature measured on the disc or on the outside of the drum is below 100 °C. 2.2.1.1.2. In the case of totally enclosed brakes, including oil immersed brakes, the temperature measured on the outside of the housing is below 50 °C. 2.2.1.1.3. The brakes have not been used for one hour before the test. 2.2.1.2. During the braking test, an axle without a brake, when this axle is capable of being declutched, shall not be connected with a braked axle. However, in case of tractors with one braked axle and an automatic engagement of the drive to all other axles during braking, all wheels are deemed to be braked. 2.2.1.3. The test shall be conducted under the following conditions: 2.2.1.3.1. The vehicle shall be laden to its maximum permissible mass specified by the manufacturer and with an unbraked axle loaded to its maximum permissible mass. The braked axle wheels shall be fitted with the largest diameter tyres intended by the manufacturer for that vehicle type when carrying the maximum permissible mass. For vehicles braking on all wheels, the front axle shall be laden to its maximum permissible mass. 2.2.1.3.2. The test shall be repeated on an unladen vehicle; in case of tractors, carrying only the driver and if necessary a person responsible for monitoring the results of the test. 2.2.1.3.3. The limits prescribed for minimum performance, both for tests with the vehicle unladen and for tests with the vehicle laden, are those laid down hereunder for each category of vehicle, the vehicle shall satisfy both the prescribed stopping distance and the prescribed mean fully developed deceleration for the relevant vehicle category, but it may not be necessary to actually measure both parameters. 2.2.1.3.4. The road shall be level. 2.2.2. Type-0 test for categories T and C vehicles 2.2.2.1. The test shall be carried out at the maximum design speed of the vehicle, with the engine disconnected. This speed may be subject to a certain margin of tolerance. However, in any case the minimum prescribed performance shall be attained. The prescribed maximum stopping distance (by the stopping distance formula) shall be calculated with the actual test speed. 2.2.2.2. To check compliance with the requirements of point 2.2.1.2.4 of Annex I, a type-0 test shall be carried out with the engine disconnected at the initial speed of not less than 98 % of the maximum design speed of the vehicle. The mean fully developed deceleration on application of the control device of the parking braking system or on application of an auxiliary control device, which permits at least partial actuation of the service braking system and the deceleration immediately before the vehicle stops shall not be less than 1,5 m/s 2 up to 30 km/h and 2,2 m/s 2 above 30 km/h. The test shall be carried out with the laden vehicle. The force exerted on the braking control device shall not exceed the specified values. 2.2.2.3. In the case of vehicles equipped with handlebar and straddle seat or equipped with steering wheel and bench seat or bucket seats in one or more rows, that are also equipped with non-disengageable transmission, as this can be proved by the manufacturer at the braking testing, the vehicle shall complete the Type-0 test with the engine connected. 2.2.3. Type-0 test for categories R and S vehicles: 2.2.3.1. The braking performance of the towed vehicle can be calculated either from the braking rate of the tractor plus the towed vehicle and the measured thrust on the coupling or, in certain cases, from the braking rate of the tractor plus the towed vehicle with only the towed vehicle being braked. The engine of the tractor shall be disconnected during the braking test. 2.2.3.2. If the towed vehicle is fitted with a compressed-air braking system, the pressure in the supply line shall not exceed 700 kPa during the brake test and the signal value in the control line shall not exceed the following values, depending on the installation: 2.2.3.2.1. 650 kPa in the pneumatic control line; 2.2.3.2.2. A digital demand value corresponding to 650 kPa (as defined in ISO 11992:2003 including ISO 11992-2:2003 and its Amd.1:2007 in the electric control line. 2.2.3.3. If the towed vehicle is fitted with a hydraulic braking system: 2.2.3.3.1. The prescribed minimum braking performance shall be achieved with a pressure at the coupling head of the control line not exceeding 11 500 kPa 2.2.3.3.2. The maximum pressure delivered at the coupling head of the control line shall not exceed 15 000 kPa. 2.2.3.4. With the exception of cases according to points 2.2.3.5 and 2.2.3.6, it is necessary for the determination of the braking rate of the towed vehicle to measure the braking rate of the tractor plus the towed vehicle and the thrust on the coupling. The tractor shall meet the requirements laid down in Appendix 1 with regard to the relation between the ratio T M /F M and the pressure p m , where: T M = sum of braking forces at the periphery of all wheels of tractors F M = total normal static reaction of road surface on wheels of tractors p m = pressure at coupling head of control line The braking rate of the towed vehicle shall be calculated according to the following formula: z R = z R + M + D/F R Where: z R = braking rate of the towed vehicle z R + M = braking rate of the tractor plus the towed vehicle D = thrust on the coupling (tractive force D > 0; compressive force D < 0) F R = total normal static reaction of road surface on all wheels of towed vehicle 2.2.3.5. If a towed vehicle has a continuous or semi-continuous braking system where the pressure in the brake actuators does not change during braking despite the dynamic axle load shifting, the towed vehicle alone may be braked. The braking rate z R of the towed vehicle shall be calculated according to the following formula: Where: R = rolling resistance value: — 0,02 in the case of vehicles with a maximum design speed not exceeding 40 km/h — 0,01 in the case of vehicles with a maximum design speed exceeding 40 km/h F M = total normal static reaction of road surface on wheels of tractors F R = total normal static reaction of road surface on all wheels of towed vehicle 2.2.3.6. Alternatively, the evaluation of the braking rate of the towed vehicle may be done by braking the towed vehicle alone. In this case the pressure used shall be the same as that measured in the brake actuators during the braking of the combination. 2.3. Type-I test (fade test) This test type shall be performed according to the requirements of points 2.3.1 or 2.3.2, as applicable. 2.3.1. With repeated braking Tractors of categories T and C shall undergo the Type-I test with repeated braking. 2.3.1.1. The service braking system of tractors covered by this Regulation shall be tested by successively applying and releasing the brakes a number of times. The vehicle shall be fully laden and tested in accordance with the conditions shown in the following table: Vehicle category Conditions v 1 [km/h] v 2 [km/h] Δt [sec] n T, C 80 % v max v 1 60 20 Where v 1 = speed at start of braking v 2 = speed at end of braking v max = maximum design speed of vehicle n = number of brake applications Δt = duration of the braking cycle (time elapsing between the initiation of one brake application and the initiation of the next). 2.3.1.1.1. In the case of tractors with a maximum design speed not exceeding 40 km/h, as an alternative to the test conditions as shown in the table of point 2.3.1.1 the conditions shown in the following table may be applied: Vehicle category Conditions v 1 [km/h] v 2 [km/h] Δt [sec] n T, C 80 % v max 0,05 v 1 60 18 2.3.1.2. If the characteristics of the vehicle do not allow for the period of time prescribed for Δt, the duration may be increased; in any event, in addition to the time necessary for braking and accelerating the vehicle, a period of 10 seconds shall be allowed in each cycle for stabilising the speed v 1 . 2.3.1.3. In these tests, the force applied to the control device shall be so adjusted as to attain a mean fully developed deceleration of 3 m/s 2 at the first application of the brakes. This force shall remain constant throughout the succeeding brake applications. 2.3.1.4. During brake applications the highest gear ratio (excluding overdrive, etc.) shall be continuously engaged. 2.3.1.5. For regaining speed after braking, the gearbox shall be used in such a way as to attain the speed v 1 in the shortest possible time (maximum acceleration allowed by the engine and gearbox). 2.3.1.6. In the case of vehicles equipped with automatic brake adjustment devices the adjustment of the brakes shall, prior to the type-I test above, be set according to the following procedures as appropriate: 2.3.1.6.1. In the case of vehicles equipped with air operated brakes the adjustment of the brakes shall be such as to enable the automatic brake adjustment device to function. For this purpose the actuator stroke shall be adjusted to: s o ≥ 1,1 × s re-adjust (the upper limit shall not exceed a value recommended by the manufacturer) Where: S re-adjust is the re-adjustment stroke according to the specification of the manufacturer of the automatic brake adjustment device, i.e. the stroke, where it starts to readjust the running clearance of the brake with an actuator pressure of 15 per cent of the brake system operating pressure but not less than 100 kPa. Where, by agreement with the technical service, it is impractical to measure the actuator stroke, the initial setting shall be agreed with the technical service. From the above condition the brake shall be operated with an actuator pressure of 30 % of the brake system operating pressure but not less than 200 kPa 50 times in succession. This shall be followed by a single brake application with an actuator pressure of > 650 kPa. 2.3.1.6.2. In the case of vehicles equipped with hydraulically operated disc brakes no setting requirements are deemed necessary. 2.3.1.6.3. In the case of vehicles equipped with hydraulically operated drum brakes the adjustment of the brakes shall be as specified by the manufacturer. 2.3.2. With continuous braking 2.3.2.1. The service braking system of vehicles of categories R1, R2, S1, R3a, R4a, S2a and R3b, R4b, S2b, where the sum of the technically permissible masses per axle does not exceed 10 000 kg for the three last vehicles' categories When the above mentioned vehicles R3a, R4a, S2a and R3b, R4b, S2, where the sum of the technically permissible masses per axle does not exceed 10 000 kg for the three last vehicles' categories, have not passed alternatively the Type-III test according to point 2.5 shall be tested in such a manner that, the vehicle being laden, the energy input to the brakes is equivalent to that recorded in the same period of time with a laden vehicle driven at a steady speed of 40 km/h on a 7 % down-gradient for a distance of 1,7 km. 2.3.2.2. The test may be carried out on a level road, the trailed vehicle being towed by an agricultural vehicle; during the test, the force applied to the control device shall be adjusted so as to keep the resistance of the towed vehicle constant (7 % of the maximum stationary axle load of the towed vehicle). If the power available for hauling is insufficient, the test can be conducted at a lower speed but over a greater distance; as shown in the following table: Speed (km/h) distance (in m) 40 1 700 30 1 950 20 2 500 15 3 100 2.3.2.3. In the case of towed vehicles equipped with automatic brake adjustment devices the adjustment of the brakes shall, prior to the Type-I test prescribed above, be set according to the procedure as laid down in point 2.5.4. 2.3.3. Hot performance 2.3.3.1. At the end of the type-I test (test described in point 2.3.1 or test described in point 2.3.2) the hot performance of the service braking system shall be measured in the same conditions (and in particular at a constant control force no greater than the mean force actually used) as for the type-0 test with the engine disconnected (the temperature conditions may be different). 2.3.3.2. For tractors this hot performance shall not be less than 80 % of that prescribed for the category in question, nor less than 60 % of the figure recorded in the type-0 test with the engine disconnected. 2.3.3.3. In the case of towed vehicles, the hot brake force at the periphery of the wheels when tested at 40 km/h shall not be less than 36 % of towed vehicles with v max > 30 km/h or 26 % of towed vehicles with v max ≤ 30 km/h of the maximum stationary wheel load, nor less than 60 % of the figure recorded in the type 0 test at the same speed. 2.3.4. Free running test In the case of tractors equipped with automatic brake adjustment devices, the brakes after completing the tests described in point 2.3.3 shall be allowed to cool to a temperature representative of a cold brake (i.e. ≤ 100 °C) and it shall be verified that the vehicle is capable of free running by fulfilling one of the following conditions: 2.3.4.1. Wheels are running freely (i.e. may be rotated by hand); 2.3.4.2. It is ascertained that when the vehicle is driven at a constant speed of v = 60 km/h with the brakes released the asymptotic temperatures shall not exceed a drum/disc temperature increase of 80 °C, then the residual brake moments are regarded as acceptable. 2.4. Type-II test (downhill behaviour test) In addition to the type-I test, tractors of categories Tb and Cb having a maximum permissible mass exceeding 12 t, shall also undergo the type-II test. 2.4.1. Laden tractor shall be tested in such a manner that the energy input is equivalent to that recorded in the same period of time with a laden tractor driven at an average speed of 30 km/h on a 6 % down-gradient for a distance of 6 km, with the appropriate gear engaged and the endurance braking system, if the vehicle is equipped with one, being used. The gear engaged shall be such that the speed of the engine (min -1 ) does not exceed the maximum value prescribed by the manufacturer. 2.4.2. For vehicles in which the energy is absorbed by the braking action of the engine alone, a tolerance of ± 5 km/h on the average speed shall be permitted, and the gear enabling the speed to be stabilised at the value closest to 30 km/h on the 6 % down-gradient shall be engaged. If the performance of the braking action of the engine alone is determined by a measurement of deceleration, it shall be sufficient if the mean deceleration measured is at least 0,5 m/s 2 . 2.4.3. At the end of the test, the hot performance of the service braking system shall be measured in the same conditions as for the type-0 test with the engine disconnected (the temperature conditions may be different). This hot performance shall give a stopping distance not exceeding the following values and a mean fully developed deceleration not less than the following values, using a control force not exceeding 60 daN: 0,15 v + (1,33 v 2 /115) (the second term corresponds to a mean fully developed deceleration d m = 3,3 m/s 2 ). 2.5. Type-III test (fade test) for laden vehicles of categories: 2.5.1. R3b, R4b, S2b where the sum of the technically permissible masses per axle exceeds 10 000 kg or alternatively of categories 2.5.2. R3a, R4a, S2a, when these vehicles have not been tested according to point 2.3.2. 2.5.3. R3b, R4b, S2b where the sum of the technically permissible masses per axle does not exceed 10 000 kg. 2.5.4. Track test 2.5.4.1. The adjustment of the brakes shall, prior to the type-III test below, be set according to the following procedures as appropriate: 2.5.4.1.1. In the case of towed vehicles equipped with air operated brakes the adjustment of the brakes shall be such as to enable the automatic brake adjustment device to function. For this purpose the actuator stroke shall be adjusted to: s o ≥ 1,1 × s re-adjust (the upper limit shall not exceed a value recommended by the manufacturer) Where: s re-adjust is the re-adjustment stroke according to the specification of the manufacturer of the automatic brake adjustment device, i.e. the stroke, where it starts to readjust the running clearance of the brake with an actuator pressure of 100 kPa. Where, by agreement with the technical service, it is impractical to measure the actuator stroke, the initial setting shall be agreed with the technical service. From the above condition the brake shall be operated with an actuator pressure of 200 kPa, 50 times in succession. This shall be followed by a single brake application with an actuator pressure of ≥ 650 kPa. 2.5.4.1.2. In the case of towed vehicles equipped with hydraulically operated disc brakes no setting requirements are deemed necessary. 2.5.4.1.3. In the case of towed vehicles equipped with hydraulically operated drum brakes the adjustment of the brakes shall be as specified by the manufacturer. 2.5.4.2. For the road test the conditions shall be as follows: Number of brake applications 20 Duration of a braking cycle 60 s Initial speed at the beginning of braking 60 km/h Braking applications In these tests, the force applied to the control device shall be so adjusted as to attain the mean fully developed deceleration of 3 m/s 2 in respect to the towed vehicle mass P R at the first brake application; this force shall remain constant throughout the succeeding brake applications. The braking rate of a towed vehicle is calculated according to the formula given in point 2.2.3.5: The speed at the end of braking: Where: z R = braking rate of the towed vehicle, z R + M = braking rate of the vehicle combination (tractor and towed vehicle), R = rolling resistance value = 0,01 F M = total normal static reaction between the road surface and the wheels of tractor (N), F R = total normal static reaction between the road surface and the wheels of towed vehicle (N), F 1 = normal static reaction of the part of the mass of the towed vehicle borne by the unbraked axle(s) (N), F 2 = normal static reaction of the part of the mass of the towed vehicle borne by the braked axle(s) (N), P R = P R = F R /g v 1 = initial speed (km/h), v 2 = final speed (km/h). 2.5.5. Hot performance At the end of the test according to point 2.5.4, the hot performance of the service braking system shall be measured under the same conditions as for the Type-0 test with, however, different temperature conditions and starting from an initial speed of 60 km/h. The hot brake-force at the periphery of the wheels shall then not be less than 40 % of the maximum stationary wheel load, and not less than 60 per cent of the figure recorded in the Type-0 test at the same speed. 2.5.6. Free running test After completing the tests described in point 2.5.5, the brakes shall be allowed to cool to a temperature representative of a cold brake (i.e. < 100 °C) and it shall be verified that the towed vehicle is capable of free running by fulfilling one of the following conditions: 2.5.6.1. Wheels are running freely (i.e. may be rotated by hand); 2.5.6.2. It is ascertained that when the towed vehicle is driven at a constant speed of v = 60 km/h with the brakes released the asymptotic temperatures shall not exceed a drum/disc temperature increase of 80 °C, then the residual brake moments are regarded as acceptable. 3. Performances of the braking systems 3.1. Vehicles of category T and C 3.1.1. Service braking systems 3.1.1.1. Under Type-0 conditions, the service braking system shall be tested under the conditions shown in the following table v max ≤ 30 km/h v max > 30 km/h v = v max = v max s (metres) ≤ 0,15 v + v 2 /92 ≤ 0,15 v + v 2 /130 d m ≥ 3,55 m/s 2 ≥ 5 m/s 2 F (foot operated control) ≤ 600 N ≤ 600 N F (hand operated control) ≤ 400 N ≤ 400 N where: v max = maximum design speed of the vehicle v = prescribed test speed s = Stopping distance d m = mean fully developed deceleration F = force applied to the control device 3.1.1.2. In the case of a tractor authorised to tow an unbraked vehicle of categories R or S, the minimum performance prescribed for the corresponding tractor (for the type-0 test with engine disconnected) shall be attained with the unbraked towed vehicle coupled to the tractor and with the unbraked towed vehicle laden to the maximum mass declared by the tractor manufacturer. The combination performance shall be verified by calculations referring to the maximum braking performance actually achieved by the tractor alone during the Type-0 test with the engine disconnected for the laden and unladen tractor (optionally also for a partially laden condition defined by the tractor manufacturer), using the following formula (no practical tests with a coupled unbraked towed vehicle are required): Where: d M + R = calculated mean fully developed deceleration of the tractor when coupled to an unbraked towed vehicle, in m/s 2 , d M = maximum mean fully developed deceleration of the tractor alone achieved during the Type-0 test with engine disconnected, in m/s 2 , P M = mass of the tractor (if applicable, including any ballast and/or supporting load) P M_laden = mass of the tractor, laden P M_par_laden = mass of the tractor, partial laden P M_unladen = mass of the tractor, unladen P R = part of the maximum mass borne by the axle(s) of a towed vehicle without a service brake which may be coupled (as declared by the tractor manufacturer) ‘P M + R ’ = combination mass (mass ‘PM’ + declared unbraked towed vehicle mass P R ) 3.1.1.2.1. Required minimum combination performance The minimum combination performance shall be not less than 4,5 m/s 2 in the case of tractors with v max > 30 km/h and not less than 3,2 m/s 2 in the case of tractors with v max ≤ 30 km/h for the laden und unladen conditions. At the discretion of the tractor manufacturer, an additional type-0 test may be carried out by the technical service for a partial laden tractor mass declared by the manufacturer in order to define the maximum permitted unbraked towed vehicle mass fulfilling the required minimum combination performance for such ‘combination mass’. The measured figures ‘d m ’ for the above mentioned load conditions and the corresponding calculated figures ‘d M + R ’ shall be recorded in the test report. The maximum declared figure for the unbraked towed vehicle mass shall not exceed 3 500 kg. 3.1.2. Secondary braking system The secondary braking system, even if the control device which actuates it is also used for other braking functions, shall give a stopping distance not exceeding the following values and a mean fully developed deceleration not less than the following values: Tractors with v max ≤ 30 km/h: 0,15 v + (v 2 /39) (the second term corresponds to a mean fully developed deceleration d m = 1,5 m/s 2 ) Tractors with v max > 30 km/h: 0,15 v + (v 2 /57) (the second term corresponds to a mean fully developed deceleration d m = 2,2 m/s 2 ) The prescribed performance shall be obtained by applying to the control device a force not exceeding 600 N on a foot or 400 N on a hand operated control device. The control device shall be so placed that it can be easily and quickly applied by the driver. 3.1.3. Parking braking system 3.1.3.1. The parking braking system shall, even if it is combined with one of the other braking devices, be capable of holding a laden tractor on an 18 % up and down gradient. This requirement shall be fulfilled even during the cooling period. The cooling period is deemed to terminate when the brakes have reached a temperature of 10 °C above ambient. 3.1.3.2. For vehicles of category T4.3, the parking braking system shall, even if it is combined with one of the other braking devices, be capable of holding a laden tractor on a 40 % up and down gradient. This requirement shall be fulfilled even during the cooling period. The cooling period is deemed to terminate when the brakes have reached a temperature of 10 °C above ambient. 3.1.3.3. Hot and cold parking braking performance test In order to verify that the parking brake is capable of holding a laden tractor on an up and down gradient as required by points 3.1.3.1 and 3.1.3.2, the measurements shall be done under the following conditions: — Heating up the brakes on a temperature ≥ 100 °C (measured at the rubbing surface of the disc or at the outside of the drum), — Hot static parking braking system test at a temperature ≥ 100 °C, — Cold static parking braking system test at a temperature ≤ ambient temperature + 10 °C. In the case of oil immersed brakes, the method by which this check is carried out shall be agreed between the vehicle manufacturer and the technical service. The method of assessment and results shall be appended to the type approval report. 3.1.3.4. On tractors to which the coupling of towed vehicles is authorised, the parking braking system of the tractor shall be capable of holding the vehicle combination, at the maximum permissible mass as specified by the tractor manufacturer, stationary on a 12 % up or down gradient. In the case that this requirement cannot be met due to physical limitations (e.g. limited available tyre/road adhesion for the tractor to generate sufficient braking forces) this requirement is deemed to be fulfilled when the alternative requirement of point 3.1.3.4 in connection with point 2.2.1.20 of Annex I is complied with. 3.1.3.4.1. The requirement of point 3.1.3.4 is considered to be fulfilled when conditions 3.1.3.4.1.1 or 3.1.3.4.1.2 below are met: 3.1.3.4.1.1. Even with the tractor engine not rotating, the combination at the maximum permissible mass remains stationary on the prescribed gradient when the activation of a single control device by the driver, from his driving seat, has applied the tractor parking braking system and the towed vehicle service braking system or only one of those two braking systems. 3.1.3.4.1.2. The tractor parking braking system can hold stationary the tractor connected to an unbraked towed vehicle having a mass equal to the highest ‘combination mass P M+R ’ mentioned in the test report. ‘P M+R ’ = combination mass (mass ‘PM’ + declared unbraked towed vehicle mass P R ) according to point 3.1.1.2 and of the test report. ‘PM’ = mass of the tractor (if applicable, including any ballast or supporting load or both of them). 3.1.3.5. A parking braking system which has to be actuated several times before attaining the prescribed performance is permissible. 3.1.4. Residual braking after transmission failure 3.1.4.1. In the case of category Tb tractors with a maximum design speed exceeding 60 km/h, the residual performance of the service braking system, in the event of failure in a part of its transmission, shall give a stopping distance not exceeding the following values and a mean fully developed deceleration not less than the following values, using a control force not exceeding 70 daN, when checked by the type-0 test with the engine disconnected from the following initial speeds for the relevant vehicle category: v [km/h] Stopping distance LADEN — [m] d m [m/s 2 ] Stopping distance UNLADEN — [m] d m [m/s 2 ] 40 1,3 1,3 That requirement shall not be construed as a departure from the requirements concerning secondary braking. 3.1.4.2. The residual braking effectiveness test shall be conducted by simulating the actual failure conditions in the service braking system. 3.2. Vehicles of the categories R and S 3.2.1. Service braking system 3.2.1.1. Requirement relating to tests of category R1 or S1 vehicles If towed vehicles of category R1 or S1 are fitted with a service braking system, the performance of the system shall meet the requirements laid down for category R2 or S2 vehicles. 3.2.1.2. Requirement relating to tests of category R2 vehicles If the service braking system is of the continuous or semi-continuous type, the sum of the forces exerted at the periphery of the braked wheels shall be at least X % of the maximum stationary wheel load. X = 50 for towed vehicle with a maximum design speed exceeding 30 km/h X = 35 for towed vehicle with a maximum design speed not exceeding 30 km/h Where the towed vehicle is fitted with a compressed-air braking system, the pressure in the control line shall not exceed 650 kPa (and/or a corresponding digital demand value as defined in ISO 11992:2003 including ISO 11992-2:2003 and its Amd.1:2007 in the electric control line) and the pressure in the supply line shall not exceed 700 kPa during the brake test. Where the towed vehicle is fitted with a hydraulic braking system, the pressure in the control line shall not exceed 11 500 kPa and the pressure in the supplementary line shall be between 1 500 kPa and 1 800 kPa during the brake test. The test speed is 60 km/h or the maximum design speed of the towed vehicle, whichever is the lower. Where the braking system is of the inertia type, it shall comply with the conditions laid down in Annex VIII. 3.2.1.3. Requirement relating to tests of category R3, R4 or S2 vehicles The sum of the forces exerted at the periphery of the braked wheels shall be at least X % of the maximum stationary wheel load. X = 50 for towed vehicle of categories R3, R4 and S2 with a maximum design speed exceeding 30 km/h X = 35 for towed vehicles of categories R3a, R4a and S2a with a maximum design speed not exceeding 30 km/h Where the towed vehicle is fitted with a compressed-air braking system, the pressure in the control line shall not exceed 650 kPa and the pressure in the supply line shall not exceed 700 kPa during the brake test. The test speed is 60 km or the maximum design speed of the towed vehicle, whichever is the lower. Where the towed vehicle is fitted with a hydraulic braking system, the pressure in the control line shall not exceed 11 500 kPa and the pressure in the supplementary line shall be between 1 500 kPa and 1 800 kPa during the brake test. 3.2.1.4. Within an axle group, wheel locking on one axle during the Type-0 test procedure is permitted. This requirement shall not be construed as a departure from the requirement of point 6.3.1. of Annex XI concerning wheel locking of directly controlled wheels. 3.2.2. Parking braking system 3.2.2.1. The parking braking system with which the towed vehicle is equipped shall be capable of holding the laden towed vehicle stationary, when separated from the tractor, on an 18 % up and down-gradient. 3.2.2.2. The requirements set out in 3.2.2.1 shall be fulfilled even during the cooling period. The cooling period is deemed to be terminated when the brakes have reached a temperature of 10 °C above ambient. 3.2.2.3. Hot and cold parking braking performance test The test requirement as specified in point 3.1.3.3 apply correspondingly. 3.2.3. Automatic braking system The automatic braking performance in the event of a failure, as described in points 2.2.1.17 and 2.2.1.18 of Annex I, when testing the laden vehicle from a speed of 40 km/h or 0,8 v max (whichever is lower), shall not be less than 13,5 % of the maximum stationary wheel load. Wheel-locking at performance levels above 13,5 % is permitted. 3.3. Response time for vehicles of categories T, C, R and S 3.3.1. Where a vehicle is fitted with a service braking system which is totally or partially dependent on a source of energy other than the muscular effort of the driver, the following requirements shall be satisfied: 3.3.1.1. In an emergency manoeuvre, the time elapsing between the moment when the control device begins to be actuated and the moment when the braking force on the least favourably placed axle reaches the level corresponding to the prescribed performance shall not exceed 0,6 seconds. 3.3.1.2. In the case of vehicles fitted with compressed-air or towed vehicles with hydraulic braking systems or tractors with a hydraulic control line, the requirements of point 3.3.1 are considered to be satisfied if the vehicle complies with the provisions of Annex III. 3.3.1.3. In the case of tractors fitted with hydraulic braking systems, the requirements of point 3.3.1 are considered to be satisfied if, in an emergency manoeuvre, the deceleration of the vehicle, or the pressure at the least favourable brake cylinder, reaches a level corresponding to the prescribed performance within 0,6 seconds. 3.3.1.4. In case of tractors with one braked axle and an automatic engagement of the drive to all other axles during braking, the requirements of point 3.3.1 are considered to be satisfied if, the tractor satisfies both the prescribed stopping distance and the prescribed mean fully developed deceleration for the relevant vehicle category according to point 3.1.1.1, but in this case it is necessary to actually measure both parameters.