Land Transport Rule
Heavy-vehicle Brakes 2006
This is Schedule 2 of the Heavy-vehicle Brakes Rule.
A. This document is the operative version of the specification. It has been developed from previous drafts dated 7 June and 11 August, and incorporates amendments as at the above date. This version will be used as part of the assessment of vehicles to be operated at the new size and weight limits. Amendments may be made in the light of operating experience, and comments should be submitted to the Chairman of the Braking Committee, Mr R A Lambert, PO Box 12843, Auckland, or to the Controller, Vehicle Standards, Land Transport Division, Ministry of Transport, Wellington.
- (a) Some concern was expressed a few years ago about the standard of braking of heavy vehicles. A committee was formed to review the situation and to recommend appropriate existing codes, or to prepare, if necessary, a code for New Zealand. A draft Code has been prepared, which, when finalised will apply to all heavy vehicles.
- (b) The review of size and weight limits for heavy vehicles was deemed to be appropriate only if a number of safety features (including braking) were improved.
- (c) Opinions vary as to which of the foregoing came first, but it is a fact that the implementation of new size and weight limits became closely linked with, and dependent on, the completion of a New Zealand Heavy Vehicle Braking Code.
- (d) Because of the complexity of the subject, and financial constraints, the Code has progressed more slowly than had been expected. During that time there has been an increasing expectation from the transport industry that the new size and weight limits were imminent. These two factors have resulted in pressure being applied to the Braking Committee to finalise the Code. The Committee believes that more investigation and testing is necessary before the Code can be finalised, and that if it were published in its present, unfinished, state, there could be implementation problems which might lead to the Code falling into disrepute.
- (e) The Ministry of Transport agrees that the introduction of a sound and workable Braking Code is too important to risk jeopardising by premature publication. Therefore introduction of the new size and weight limits is no longer dependent on the full Code, as such, but this specification may be seen as a first step towards it.
- (f) This specification is an additional requirement for vehicle combinations exceeding 39 tonnes, and it does not replace the current braking requirements. Those will remain part of the normal certificate of fitness inspection.
1. Scope and limitations
A. This specification applies only to vehicles which will be used in any combination at a GCM exceeding 39 tonnes.
B. In this specification ‘operator’ may mean the owner, the operator, or the driver, as appropriate.
C. Approval of vehicles to this code will be specific, ie will not be a ‘type approval’. Vehicle combinations must be semi-dedicated and will be specified on the approval. The test is to be applied to every specific vehicle and vehicle combination except as indicated below. For example a fleet of three trucks and three trailers may be proposed for use in any combination, but each combination must be specified, and the approval for each truck will list each trailer.
D. Where identical trailers or semi-trailers are proposed for use with more than one truck or tractor, the testing of every combination will not be necessary provided that:
- (a) B-train semi-trailers are a dedicated pair, without exception
- (b) at least one trailer must be tested with every truck or tractor
- (c) every trailer must be tested with at least one truck or tractor
- (d) where a difference in performance between trailers is detected, then the trailer with the poorer performance (lower deceleration, greater deviation from straight) shall either be used as the one trailer specified in (a) or shall be deleted as a proposed vehicle in combination
- (e) similarly a truck or tractor with lower performance shall be used as the one truck or tractor specified in (b)
- (f) ‘identical’ means having nominally identical
- (1) structure (chassis, axle spacings, manufacturer, etc)
- (2) axles, suspensions, tyres
- (3) foundation brakes (drum dia and width, lever length, chamber size, etc)
- (4) braking system (supply and control systems)
- (5) towing connections.
2. Equipment requirements
A. Service brakes must operate on every axle.
B. In case of braking failure in any of the vehicles in a combination, each vehicle in the combination must either apply its brakes automatically, or leave the brakes under the control of the driver.
C. Every vehicle (including trailers and semi-trailers) must have an emergency braking system which is substantially independent of the service braking system, and which operates on at least half of the axles on each vehicle, and which is operable from one control within easy reach of the driver in his normal seating position. This emergency braking would generally operate by the force of the springs in spring brake chambers, but the inclusion of ordinary air chamber operation is not prohibited; e.g. a three-axle trailer with air on the front axle and spring brakes on the rear bogie.
D. Every vehicle (including trailers and semi-trailers) must have a parking brake system substantially independent of the service brakes, and which:
- (a) operates on at least half of the axles on each vehicle and
- (b) will hold the vehicle when fully laden on a 1 in 5 grade for an indefinite period and
- (c) is operable by the driver in his normal seating position.
E. All air connections between towing and towed vehicle shall be of the two-line type (excluding auxiliaries).
F. Air-line identification
- (a) Connections that are physically capable of being incorrectly connected shall be colour-coded thus: control line = yellow, green or blue; supply line = red.
- (b) It is recommended that couplings that cannot be incorrectly connected are colour-coded in the same way.
- (a) At the interface coupling (towing to towed vehicle), the service (control) line shall be to the left of the vehicle, and the emergency (supply) line shall be to the right.
- (b) Couplings shall be on the longitudinal centre-line of the vehicle, or close to it on the right-hand side.
- (c) In each case, left and right correspond to a person facing in the direction of normal travel.
H. Every vehicle submitted for testing to this specification must have travelled at least 500 km beforehand, with the vehicle braking equipment as fitted to the vehicle at the time of testing. The intention of this clause is to allow the brake system to ‘bed in’, especially the friction linings. If there is reasonable cause to suspect that this requirement has not been complied with, the vehicle shall be rejected.
3. Pre-conditions for test
A. Each vehicle must have a current certificate of fitness, and must be up to certificate of fitness standard.
B. Towing connections must comply with NZS 5446 (full trailers) or NZS 5450/5451 (semi-trailers) as appropriate.
C. Load anchorage points must comply with NZS 5444.
D. Note that under (B) and (C) above, compliance with drafts current at the time will be deemed acceptable.
E. Loads must be attached in accordance with the Truck Loading Code.
F. Operator must complete data sheet for each submitted vehicle.
G. Operator must mark the outer sidewall of each tyre with four equispaced radial white lines approx 100 mm wide, using acrylic paint or similar medium.
H. Each axle must be weighed before the test within a time specified by the Auto Surveyor.
I. Axle loadings must not exceed those to be permitted under new size and weight limits.
4. Test requirements
A. Each combination of vehicles must satisfactorily perform three successive controlled emergency stops from 50 km/hr when fully laden, using the service brakes only.
- (a) This requirement is to ensure that one satisfactory stop is not a fluke; and also makes some provision for fade.
- (b) The number of stops may be reduced by the automotive surveyor in the light of testing experience, e.g. when testing a group of ‘identical’ combinations, if the first two stops with the second and subsequent combinations produce results effectively identical to the first combination, then the third test may be waived.
B. Each combination of vehicles must also satisfactorily perform one controlled stop from 50 km/hr when fully laden, using the emergency brakes only.
C. The tests shall be carried out on a flat straight sealed road (or equivalent surface) marked with lanes 3.7m wide, and the vehicle shall be in the centre of the lane each time braking commences.
D. ‘Fully laden’ means laden to the maximum permitted under the new size and weight limits, with the payload distributed as evenly as possible along (or in) the load carrying portion of the vehicles. The axle loads shall be verified immediately before or after the test. In this context ‘immediately’ need not be taken literally, provided that there is no opportunity for off-loading between weighing and test.
E. ‘50 km/hr’ means between 49 and 51 km/hr according to the towing vehicles speedometer unless there is reason to doubt the accuracy of that instrument, in which case calibration shall be arranged to the satisfaction of the Automotive Surveyor or Traffic Officer.
F. ‘Controlled’ means:
- (a) in any axle group in which lockup occurs, at least one complete axle shall not lockup at any speed above 20 km/hr;
- (b) every vehicle must stay wholly within the 3.7m lane width. This point may be determined either by an observer, or by the use of traffic cones;
- (c) there must be no significant axle hop during the stop. In this context ‘significant’ means either violent or of long duration.
G. ‘Satisfactorily’ means that:
- (a) using the service brakes, the average deceleration rate shall be not less than .41g (41%) for at least two of the stops, and shall be not less .39g (39%) for the third stop;
- (b) using the emergency brakes, the average deceleration rate shall be not less than .25g (25%);
- (c) for the purposes of this clause, the stopping distances or times tabled in Appendix A to Section 2 of Chapter 2 in The Automotive Surveyors Manual may be used to determine average deceleration;
- (d) The load must not be disturbed by any significant amount.
H. ‘Using the service brakes only’ means that the transmission must be in neutral or the clutch disengaged so that there is no retarding effect from either the engine itself or from any exhaust brake or other type of retarder.
5. The vehicle or vehicles must be presented by the operator at a time and place specified by the Automotive Surveyor. The test will be conducted with the operator driving, one Automotive Surveyor in the cab, and one or more Automotive Surveyors observing.
A. Alternative arrangements may be made by the Automotive Surveyor in charge of the testing, provided that the spirit and intent of the specification is met.
6. Ideally the test site will be flat straight road of say 0.5 km, with minimum street furniture, and with ample flat or approximately flat run-off areas. The test must be conducted when there is little or no other traffic and there must be suitable turning areas, or roads forming a circuit. The test area must be near a weighbridge, or portable weighing equipment must be available.
7. Automotive Surveyors and Traffic Officers will cooperate to ensure that the tests may be carried out as smoothly as possible, and with no danger or inconvenience to other road users. If necessary, the road will be closed to other traffic for the duration of the tests.
8. The test described in this specification is in addition to the normal certificate of fitness inspection. A fee will be charged based on the time taken, at the standard charge-out rate for Automotive Surveyors and Traffic Officers.
9. Subsequent certificate of fitness inspections will verify that the details shown on the data sheet are still correct.
10. Operators are to be recommended to carry out sufficient checking and/or testing beforehand, so that time is not wasted during the official tests. Operators are to be reminded that any such testing must not endanger or inconvenience other road users, and that such testing should be carried out at lower speeds initially. Any such advice must include the warning that the current weight limits still apply.
11. Future requirements
A. It is likely that this code will be applied only to existing vehicles. In the event that a ‘new’ vehicle is tested, the following additional requirements will apply (these will either be part of the final brake code or subject to new Regulations).
- (a) Power connections (air and electrical) on towing vehicles are to be installed by the vehicle manufacturer or accredited agent.
This may become a general requirement for every vehicle which is sold as being capable of towing ie has a towing rating.
- (b) Quick release air-line couplings are to be identified by the supplier as to their suitability ie whether or not suitable for the front end of a semi-trailer.
- (c) Development is presently underway on a test rig to check towing vehicle air connections. This will, in due course become part of the certificate of fitness inspection. Towing vehicles that have incorrect connections, or which cannot meet the recovery times when the rig is connected, will be refused a certificate of fitness.
- (d) It is possible that a requirement may be introduced for graduated brakes (service brakes) to operate from one control only, e.g. separate graduated hand controls for trailer brakes will not be permitted.
In such a case, trailer brake hand controls will only be permitted, if they are of the full-on or full-off type.
Vehicle Standards Bulletin – Excerpt November 29, 1988
A. 44 tonne assessment and brake test - Errata
1. Instructions to Automotive Surveyors
- (a) Page 2, item C.8.e) – should read ‘DZ 5444 or NZS 5444’
- (b) Page 2, item C.8.h) – should read ‘Check that truck wheelbase is not less than 4250 mm’
Effectively only applicable to 6x4 trucks and drawbar trailers
- (c) Page 2, item C.8.j)T) – should read ‘Tyres and Rims’
- (d) Other minor typographical errors should be readily detectable by the discerning reader.
2. Instructions to Operators
- (a) Page 1, item B.1.a) – add ‘Except that interim permits may be obtained from MoT Head Office, applications should be marked for Traffic Engineering’
- (b) Page 1, item B.1.e)iv) – add ‘for all combinations over 39 tonnes and all A-trains over 19 metres.
3. Heavy Vehicle Braking Specification
- (a) Page 3, item 2.D – add ‘and which must hold the vehicle for an indefinite period on a gradient of 1 in 5’
Note that the parking brake is required to be substantially independent of the service brakes, but can be combined with the emergency brakes.
- (b) Page 3, item2.G.a) – should read
‘service (control) line shall be to the LEFT
emergency (supply) line shall be to the RIGHT’.
4. Data Sheet - MOT 4076A
- (a) Wheel base (Minimum 4250 mm) effectively pertains only to 6x4 truck.
5. Loading Certificate – MOT 4011A
- (a) Under ‘Permitted Combinations’ the right-hand side is intended for recording the second semi-trailer of a B-train. The two semi-trailers of each B-train assessed should be recorded on the same line. If the combination is not a B-train, the right-hand side should be crossed, and any rows of the left-hand side that are not filled in should also be crossed, or otherwise rendered unuseable.
R L Reynolds
Controller, Vehicle Standards
Assessment for New Size and Weight Limits December 6, 1988
Instructions to Operators
A. If you have a vehicle or combination of vehicles that you wish to operate at the new size and weight limits
- 1. Please read these notes carefully.
- 2. Obtain copies of the documents described.
- 3. Ensure that your vehicle or combination complies with the pre-conditions on or before the stated dates.
- 4. If you want a combination to operate in excess of 39 tonnes, follow the directions given in (C) below.
B. The package for the new size and weight limits has the following features:
1. No changes will take place until EVERY part of the package is complied with:
- (a) The Traffic Regulations Amendment must be finalised and gazetted, to authorise the new dimensions, except that interim permits are available from MoT Head Office; applications should be marked for Traffic Engineering.
- (b) The Heavy Motor Vehicle Regulations must be finalised and gazetted to authorise the new weight limits.
- (c) Individual vehicles and/or combinations must comply with the dimension requirements.
- (d) Individual vehicle, axle, and tyre ratings must be not less than the proposed loadings.
Note that tyre, axle, and GVM and GCM ratings for all vehicles operating at the new size and weight limits:
- (I) Must be verified by Head Office unless already in the Chassis Rating Book Rating Book.
- (II) Must be not more than the manufacturer’s rating, unless uprated under the relevant criteria in the modification policy.
- (III) May NOT include the 25% allowance on GVM or GCM.
- (e) The published pre-conditions must be met by each vehicle or combination (for timing see B2 to B6 below):
- (I) drawbars/drawbeams to NZS 5446
- (II) fifth wheels/kingpins to NZS 5450/5451
- (III) load anchorage points to NZS 5444
- (IV) tandem drive on tractor or trucks for all combinations over 39 tonnes and all A-trains over 19 metres long
- (V) load sharing suspensions
- (VI) uniform suspension medium within axle groups new braking requirements.
- (f) New Zealand Standards (NZS) may be obtained from Standards Association of New Zealand, Private Bag, Wellington.The fifth wheel, king pin, and load anchorage standards are, at the time of writing, still only in draft form. However, compliance with them in that form is deemed acceptable.
- (g) New braking requirements will be:
- (I) immediately for 39+ tonnes, is by compliance with the Heavy Vehicle Braking Specification, available from MoT
- (II) in due course for all vehicles, will be by compliance with a Braking Code that is still being developed.
2. All new vehicles will be required to comply with the new dimension limits and the pre-conditions listed above. For practical purposes this will be interpreted as:
- (a) all vehicles first registered on or after 1 January 1989 will be expected to comply not later than 1 June 1989
- (b) all vehicles first registered on or after 1 June 1989 will be expected to comply immediately.
3. All existing vehicles which are intended to take advantage of the new weight limits must also comply with the new dimensions. Existing vehicles that do not comply, may continue to be operated at the old limits.
4. All existing vehicles will be expected to comply with drawbar/drawbeam standard by 1 January 1989.
5. All existing vehicles will be expected to comply with fifth wheel/kingpin, and load anchorage point standards within a reasonable time (proposed 1 June 1990).
6. All vehicle combinations to be operated in excess of 39 tonnes must be assessed and tested for compliance.
C. Combinations to exceed 39 tonnes.
1. Obtain from SANZ, as appropriate:
- (a) NZS 5446
- (b) NZS 5450 or DZ 5450
- (c) NZS 5451 or DZ 5451
- (d) NZS 5444 or DZ 5444.
2. Obtain from a MoT Vehicle Testing Station:
- (a) Heavy Vehicle Braking Specification
- (b) Vehicle Data Sheet,( MOT 4076A) (original and carbon) for each vehicle.
3. Check that each vehicle complies with the items listed in (B1e), and that the braking performance complies with the specification.
4. Fill in the Data Sheet as far as you are able, and present it with any outstanding certificates and assessment fee ($200) to the Testing Station.
5. Arrange an appointment with the testing station manager for the assessment. Note that this may have to be in a regional centre rather than locally.
6. Turn up for the appointment:
- (a) on time
- (b) with every tyre painted with four white radial stripes 100 mm wide
- (c) with the combination loaded as close to the new maximum limit as possible, in accordance with the truck loading code.
Note that the load should be typical of that normally carried (e.g. logs on a logging trailer) except that the load should not be livestock, even if the combination is normally used for carrying livestock.
7. The assessment fee is for cost-recovery, therefore a broken appointment will mean that the fee is forfeit.
R L Reynolds
Senior Automotive Engineer
A Division of the Ministry of Transport
29 May 1989
Amendment to the HEAVY VEHICLE BRAKING SPECIFICATION
The format and complexity of the equipment requirements in the HMV Regulations has meant that the most convenient way to treat braking is to amend the Braking Specification.
Delete Sub-Clause lA and substitute the following:
1. Scope and Limitations
- (I) All requirements of this specification shall apply to all vehicles which will be used in any combination at a GCM exceeding 39 tonnes: except that the Controller of Vehicle Standards may approve the use of an alternative code or specification on specified vehicles for evaluation purposes.
- (II) Any vehicle which will not be used in a combination at a GCM exceeding 39 tonnes will be deemed to comply with this specification if it passes the requirements for a Certificate of Fitness; except that an Automotive Surveyor may, at his discretion, apply the criteria set out in Part 4 of this specification as an aid to assessing compliance with the Certificate of Fitness requirements.
- (III) This specification will be automatically superseded when the Secretary for Transport approves the Heavy Vehicle Braking Code (by whatever name it is finally known) currently under development by the Heavy Vehicle Braking Committee. The final code may contain requirements for existing vehicles. All existing vehicles will be expected to comply with any such requirements, whether or not they have been tested in accordance with this specification.
R L Reynolds
Controller Vehicle Standards
PEARSE HOUSE 225 WILLIS STREET P.O. BOX 27459
WELLINGTON NEW ZEALAND
TELEPHONE (04) 828-300 FAX (04) 855-699, 855-799
Land Transport Rule - Heavy-vehicle Brakes - Rule 32015
Land Transport Safety Authority of New Zealand, Te Mana Marutau Waka Whenua o Aotearoa