This is Schedule 1 of the Heavy-vehicle Brakes Rule.

 

Schedule 1     Interim Performance specification for Heavy Vehicle Braking

1.0     Introduction

1.1     This Specification is the braking standard that combinations of vehicles must comply with.

1.2     Regulation 16(A), paragraphs 1(a) and 6(d) of the Heavy Motor Vehicle Regulations 1974, require that all vehicle combinations, operating in excess of 39 tonnes GCM, shall comply with this Standard. This requirement is in addition to the normal Certificate of Fitness inspection. It does not replace the current statutory braking requirements.

1.3     A fee will be charged for this test which will be based on the time taken and the standard charge out rate for authorised vehicle inspectors and Police Officers.

 

2.0     Definitions

2.1     ‘Authorised Vehicle Inspector(s)’ means a person who is employed as a vehicle inspector by an authorised vehicle inspection organisation.

2.2     ‘Controlled’ means the braking performance of the vehicle being tested during a prescribed brake application. Refer Cl. 6.4.

2.3     ‘50 km/hr’ means between 49 and 51 km/hr according to the towing vehicles speedometer.

2.4     ‘Fully laden’ means laden to the maximum permitted under the current size and weight limits.

2.5     ‘Full trailer’ means a towed vehicle fitted with at least two axle set and equipped with a draw bar which controls the direction of the front axle(s) and which transmits no significant static load to the towing vehicle.

2.6     ‘GCM’ means Gross Combination Mass, means the sum of the GVM’s of the towing and towed trailer(s) used in a combination. It is the lesser of that specified by the manufacturer of the towing vehicle or the New Zealand regulations.

2.7     ‘GVM’ means the maximum laden mass of a motor vehicle as specified by the manufacturer or the New Zealand regulations, whichever is the lesser.

2.8     ‘Identical’ means having nominally identical:

• - Structure (chassis, axle spacings, manufacturer, etc). and
• - Axles, suspensions, tyres. and
• - Foundation brakes (drum diameter, brake shoe width, lever length, chamber size, etc). and
• - Braking system (supply and control systems). and
• - Towing connections.

2.9     ‘Operator’ means the owner, the operator, or the driver, as appropriate.

2.10     ‘Satisfactorily’ describes the braking performance of the vehicle under test that meets the performance specified in Cl. 6.5.

2.11     ‘Semi-trailer’ means a towed vehicle having one axle set positioned behind the centre of gravity of the vehicle(when laden) so that a substantial portion of the laden weight is superimposed on the towing vehicle.

2.12     ‘Significant’ means either violent or of long duration.

2.13     ‘Trailer’ means a towed vehicle.

2.14     ‘Type Approval’ means

2.15     ‘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.

 

3.0     Scope

3.1     The requirements of this Specification shall apply to all vehicles which operate in any combination at a GCM exceeding 39 tonnes. This Specification applies only to those vehicles that have a GCM rating.

3.2     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. An vehicle inspector may, at his discretion, apply the criteria set out in Section 6 of this Specification as an aid to assessing compliance with the Certificate of Fitness requirements.

3.3     From 1 July 1994, this Specification shall only apply to those vehicles that are already in service.

By 1 July 1995, this Specification will have been phased out and the Heavy Vehicle Brake Code will have become the sole acceptable braking standard for heavy goods service vehicles operating in combination, in excess of 39 tonnes.

3.4     Compliance of vehicles with this Specification will be specific. There will be no ‘type approval’. Vehicle combinations must be semi-dedicated and will be specified on the approval certificate. 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. Refer to Cl. 3.5.

3.5     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 unit.
• (c) Every trailer must be tested with at least one truck or tractor unit.
• (d) Where a difference in performance between trailers is detected, then the trailer with the poorer performance (lower deceleration, greater deviation from the straight line of travel) shall either be used as the one trailer specified in (b) above, 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 (c) above.

 

4.0     Equipment requirements

4.1     Service brakes must operate on every axle.

4.2     In case of a service braking failure due to a loss of air or operating medium from 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.

4.3     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 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 group of axles.

4.4     Every vehicle, including trailers and semi-trailers, must have a parking brake system substantially independent of service brakes 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.

4.5     All air connections between towing and towed vehicle shall be of the two-line type (excluding auxiliaries).

Where air connections are physically capable of being incorrectly connected, they shall be colour coded in the following manner:

• (a) Control (Service) lines shall be coloured either yellow, green or blue. The Supply (Emergency) lines shall be coloured red.
• (b) It is recommended that couplings that cannot be incorrectly connected are colour-coded in the same way.

4.6     At the interface coupling (towing to towed vehicle), the service (control) line shall be on the left of the coupling, and the emergency (supply) line shall be to the right. Couplings shall be on the longitudinal centre-line of the vehicle, or close to it on the right-hand side.

In each case, left and right correspond to a person facing in the direction of normal travel.

4.7     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.

 

5.0     Prerequisites for carrying out the braking test

5.1     Every vehicle being tested for compliance with this Specification shall:

• - Have a current certificate of fitness, and must be up to certificate of fitness standard.
• - Towing connections must comply as follows:
  • Full trailers: the current edition of NZS 5446; or
  • Semi- trailers: the current edition of NZS 5450/5451, as appropriate.
• - Load anchorage points must comply with the current edition of NZS 5444.
• - Loads must be attached in accordance with the Truck Loading Code.
• - Operator must complete data sheet for each submitted vehicle.
• - Operator must mark the outer sidewall of each tyre with four equi-spaced radial white lines approximately 100 mm wide, using acrylic paint or similar medium.
• - Each axle must be weighed before the test within a time specified by the vehicle inspector.
• - Axle loadings must not exceed the legal limits.

5.2     Operators are to be encouraged to carry out sufficient checking and/or testing beforehand, so that time is not wasted during the official tests.

They are also 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.

 

6.0     Test requirements

6.1     Each combination of vehicles must satisfactorily perform three successive controlled emergency stops from 50 km/hr, when fully laden using only the service brakes. This is to ensure that one satisfactory stop is not a fluke and that some provision for fade is made.

6.2     The number of stops may be reduced by the vehicle inspector 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.

6.3     Where there is reason to doubt the accuracy of the speedometer, the instrument shall be calibrated to the satisfaction of the vehicle inspector.

6.4     During a satisfactory brake test brake application:

• - Where lock up occurs in an axle group, at least one complete axle shall not lockup at any speed above 20 km/hr.
• - 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.
• - There must be no significant axle hop during the stop.

6.5     Each vehicle combination is deemed to have undergone a satisfactory brake test, if

• - No lockup of any axle occurs at speeds over 20 km/hr.
• - The combination remains with the 3.7m lane during stopping.
• - No significant axle hop takes place.

and the braking performance equals or exceeds:

• - For service brakes, the average deceleration rate shall be not less than 0.41g (41%) for at least two of the stops, and shall be not less 0.39g (39%) for the third stop.
• - Using the emergency brakes, the average deceleration rate shall be not less than 0.25g (25%).
• - Using only the emergency brake, perform one controlled stop from 50 km/hr when fully laden.

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.

The load must not be disturbed by any significant amount.

 

7.0     Conduct of the braking tests

7.1     The vehicle or vehicles must be presented by the operator at a time and place specified by the vehicle inspector. The test will be conducted with the operator driving, with one vehicle inspector in the cab, and one or more observing.

7.2     Alternative arrangements may be made by the vehicle inspector in charge of the testing, provided that the spirit and intent of this Specification is met.

7.3     The payload shall be distributed as evenly as possible over 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.

7.4     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.

Ideally the test site will be flat straight road of say 0.5 km, with a minimum of 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.

7.5     Vehicle inspectors shall cooperate with Police Officers to ensure that the tests are carried out as smoothly as possible, and with no danger or inconvenience to other road users. Where necessary, the road should be closed to other traffic for the duration of the tests. Vehicle inspectors should liaise with police and local authorities.

7.6     Subsequent certificate of fitness inspections will verify that the details shown on the data sheet are still correct.

 

8.0     Required certification

8.1     For this Specification to be complied with, each vehicle within the combination shall have the following forms completed in full:

• - MOT4076A; Heavy Motor Vehicle Size and Weight Limits, Data Sheet.
• - MOT4076B; Heavy Motor Vehicle Braking Specification, Test Results.
• - MOT4011; Loading Certificate.
• - MOT4011A, Loading Certificate. Gross Combination Weight Exceeding 39 Tonne.

The forms MOT 4011 and 4011A must be displayed on the vehicle at all times as it is these two forms that testify that a particular vehicle complies with this Specification. The white form (top copy) is to be given to the vehicle’s operator and the yellow duplicate retained by the testing station.

 

9.0     Braking specification as applied to new vehicles

9.1     Where a ‘new’ vehicle is tested, the following additional requirements will apply:

• - Power connections (air and electrical) on towing vehicles are to be installed by the vehicle’s manufacturer or accredited agent.
• - 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.
• - 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.
• - Graduated hand controls for trailer brakes will not be permitted. Only trailer brake hand controls will only a permitted, if they are of the full-on or full-off type.