New regulations —today and tomorrow
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D RAKING and allied regulations have been in the news for a long
time now—confusingly so for many readers. After long deliberations with interested parties the Minister of Transport introduced an amendment to the then existing Construction and Use Regulations on August 21 1964 which, among other provisions, introduced the concept of plating of vehicles relative to permissible weights and braking efficiencies. These requirements have subsequently been consolidated and expanded in the Motor Vehicles (Construction and Use) Regulations 1966 which came into operation on December 11966.
Throughout this period of several years COMMERCIAL MOTOR has continued to keep readers informed on developments, including official announcements and contributions on this topic at trade association and other conferences.
Despite this considerable coverage, however, inquiries from readers confirm that there is still a lack of understanding as to current braking requirements and also the underlying reasons for these changes.
It is therefore opportune to take stock of the present position by reproducing at length a paper read by Mr. D. E. Baker, senior engineer, Ministry of Transport, at the annual conference of the National Association of Furniture Warehousemen and Removers held in Edinburgh this month.
The background As a background to the new provisions, Mr. Baker first made the following comment:—
"The Regulations have always required that the majority of motor vehicles should have at least two braking systems, although until recently the Regulations had not been specific as to what was required in the way of brake performance. The wording was to the effect that, in the event of a failure of any part in one system, there should remain brakes capable of bringing the vehicle to rest within a reasonable distance under the most adverse conditions.
"The interpretation of this phrase was, of course, fairly wide and the result was that police forces and magistrates' courts up and down the country had different ideas as to what brake performance satisfied this specification. Matters were brought to a head by the introduction of the vehicle testing scheme for cars, light commercial vehicles and motorcycles, when it was realized that some more definite guidance would have to be given to testing station personnel as to what constituted a satisfactory brake.
"Accordingly, specific efficiencies were written into the regulations for these classes of vehicles and since 1960, which was the date of the commencement of vehicle testing schemes, most have had to provide efficiencies of 50 per cent on one system and 25 per cent on the other."
Mr. Baker then explained what the efficiency figures mean. "Imagine for a moment a vehicle running on a dry level road, the surface of which has a very high resistance to skidding. Now, if the brakes were such that they could apply a total braking force at the wheels equivalent to the weight of the vehicle, then the braking efficiency would be 100 per cent, which is a retardation equal and opposite to the acceleration due to gravity, that is, 32 feet per second per second or lg.
"In practice the maximum brake efficiency is limited to something like 80/85 per cent by virtue of the fact that the average road surface has a limited resistance to skidding. In wet conditions, of course, the figure is lower still falling to less than 10/15 per cent on ice."
A further positive step in the specification al braking efficiency took place with the amendments permitting higher maximum gross weights to certain new vehicles in 1964, Mr. Baker continued. "It was made a condition of the increase that such vehicles should be able to obtain brake efficiency of 50 per cent and 25 per cent of the two separate systems.
"A further step will come into effect next January when the generality of goods vehicles constructed on or after January 1, 1968 will be required to have a service or primary brake efficiency of 50 per cent and emergency or statutory efficiency after failure of one part of 25 per cent under any condition of load.
"Also, when these vehicles are drawing trailers, whether of the articulated or rigid draw-bar type, the same efficiencies must be obtainable. Furthermore, a specified performance is required of the parking brake, which must be capable of holding the vehicle or vehicle combination stationary at all times on a gradient of at least 1 in 6.25. This is roughly equivalent to a brake efficiency of 16 per cent."
Purpose of the requirements
Commenting that the prime purpose of these requirements was to raise the standard of brake performance, Mr. Baker said that the majority of vehicles now being manufactured could obtain efficiencies of 50 per cent on the service braking system. But handbrakes had been lamentably low in efficiency in the past, and the new requirements would ensure that in event of failure in the service brake, there would still be available to the driver brakes capable of giving at least 25 per cent efficiency, and in the case of articulated vehicles some proportion of this efficiency was to be supplied by the trailer brakes.
"Turning now to the efficiencies which existing vehicles will have to obtain," Mr. Baker continued, "these have been set at 45 per cent and 20 per cent for rigid two-axle vehicles and 40 per cent and 15 per cent for three and four-axles rigids, articulated vehicles and vehicles towing separate trailers. . . . Most manufacturers have estimated that the vehicles up to 10 years' old can obtain these efficiencies without modification. . . It can be argued that the efficiencies required of existing vehicles are not unduly onerous, and they have been regularly obtained by vehicle examiners during road tests over the past years. "However, there may be cases, for instance six-wheel conversions, where frequent g ttention to brake adjustments may be necessary in order to keep vehicles up to scratch. So far as existing vehicles are concerned, it is proposed that the lower brake efficiencies being specified should continue for a limited period only of, say, five years, after which vehicles will be required to meet a higher standard proposed for new vehicles so far as braking efficiency is concerned, but not the more exacting construction requirements.
"During this period operators will have the cpportunity of bringing vehicles up to the higher standards required by the date proposed. An alternative might be to accept a lower plated weight at which the required efficiencies can be met or to take vehicles out of service."
Plating of vehicles was then explained by Mr. Baker. "Another new regulation effective from January I, 1968 requires new goods vehicles and trailers to be fitted with a plate in a conspicuous and readily accessible position. This plate must contain particulars of the maximum weight each axle is designed to carry and the maximum gross weight of the vehicle. . . Steps are also being taken to see that all existing goods vehicles will be plated in due course by the Ministry at some 70 official testing stations to be set up under powers which are contained in the Road Safety Bill now being examined in the House of Lords." (The Bill has since been through the Lords and accepted, as amended, by the Commons.)
Clear distinction
Here Mr. Baker emphasized the clear distinction between the plating of vehicles by the manufacturers under the Construction and Use Regulations due to come into force on January 1, 1968 and the plating of vehicles by the Ministry under the provision of the Bill.
"The former plate is required by all new vehicles of the prescribed classes after the effective date. Without such a plate, those vehicles cannot take advantage of the provision of Regulation 70 and 71 which allow higher operating weights to properly braked vehicles and combinations. There is, however, nothing in the Regulations to say that the weight shown on such a plate is not to be exceeded.
"Ministry plating under the provisions of the Road Safety Bill, on the other hand, will be accompanied by regulations making it an offence for a vehicle of a class of which such plating is applied by the Minister to operate without a plating certificate or to exceed the Ministry plated weights."
Commenting on the annual testing of goods vehicles which it is intended to bring into force early next year, he said the initial testing and plating of a vehicle would in most cases be carried out simultaneously. "What we anticipate will happen," Mr. Baker forecast, "is that during the first two years of operation from 1968
onwards, each vehicle will be called for testing and plating to one of the Government-owned testing stations where a plating certificate for attention by the owner and a corresponding plate for fixing to the vehicle will be issued. On these will be stated the maximum axle weights and the maximum gross vehicle weight, and probably also the maximum permissible weights under the existing Construction and Use Regulations for combinations of vehicles.
"Should the vehicle fail the test, then a test certificate will not be issued and the vehicle will not receive its braking certificate or plate either. A further test will be necessary if any defects have been noticed at the first test and the necessary will then be issued if the defects have been corrected.
"Plating will be carried out on the basis of weights shown in a standard list, which will be compiled by the Ministry after consultation with the original manufacturers and others. Should the vehicle be one which does not fall within the standard list, then the plated weights will be assessed at the testing station according to agreed procedure.
"It is hoped to complete the testing and plating of all existing vehicles by the end of 1969, and subsequently each vehicle (including of course vehicles first coming into use after the end of 1969) will be called in annually for a test.
"For annual testing most vehicles will be accepted in the unladen conditions, the efficiency on the brakes being assessed as if they were laden to the maximum gross weight determined at the time of plating. .
"Testing and plating as indicated also extends to trailers but at the moment it seems as if it might be more practicable to leave the examination of these to the last, and it is therefore possible that they will not be compulsorily called in much before the middle of 1969".
"Furthermore, having plated and tested existing vehicles and type-approved new vehicles it is clear that attention must be paid to conversions and alterations which may affect the performance or carrying capacity of the vehicle and the Ministry is considering possible methods of dealing with this difficult problem."
Here Mr. Baker stated that the Road Safety Bill made provision for the re-examination and replating of a vehicle either compulsorily or on the application of the owner or operator, if there was a notifiable alteration.
"This means, for instance," he continued, "that a vehicle designed to operate at X tons, and plated accordingly (subject to overriding weight limits under the Construction and Use Regulations), can be down-plated if the owner wants to carry bulky but light goods, not requiring tyres of the rating appropriate to the original plated weight. Conversely, an operator who fits an extra axle may be able, if the modification is satisfactory, to get his vehicle plated up."
The Bill also contained provisions for regulations requiring operators to carry out regular maintenance inspections and keep records of them. Such regulations as with others in the Bill, would have to be the subject of consultation with interested organizations. Overall therefore, Mr. Baker concluded, the Ministry was concerned to improve the braking performance of vehicles, to avoid the consequences of overloading and ensure regular and effective maintenance of all vehicles.