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The cost of legal loading
Page 139
Page 140
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Most of the long-awaited plating and testing stations are in business in England and Wales from October 1. Robert Harrison, Fellow of the Graduate Centre for Management Studies, Birmingham, conducted a research project for the Ministry of Transport into the cost effects of the 1968 Braking and Plating Regulations. His hitherto unpublished report forms the basis of four special articles which are particularly topical.
IN 1967 the Ministry of Transport staged a sizeable test weighing operation at four sites in the London area—Barking, Havering, Northolt and South Mimms. The weighing was arranged in lay-bys adjacent to trunk roads and utilized permanent weighing devices supervised by the Department of Weights and Measures.
The selected vehicles were weighed by axle and details noted by the checking staff included body type, make, model, unladen weight, licence class, load and description, and haulier's address. Over 2,000 vehicles were sampled. No prosecutions were sought because it was felt that if drivers had the slightest suspicion that it was part of an enforcement drive, the "grape vine" would ensure that heavily laden vehicles took alternative routes. There were many occasions, Mr. Harrison notes, "when officers' fingers instinctively felt towards their notebooks, especially when a certain driver commented, thought the steering was a bit stiff' on hearing that his two-axle vehicle was grossing well over 21 tons".
Two standards
The weighing data was analysed using two standards. The first was a liberal interpretation of the old regulations. A vehicle was considered overloaded if it carried (a) more than 10 tons on any axle yet within gross limits, or (b) more than the gross limit for the particular class to which the vehicle belonged. For example, a two-axle vehicle had to gross more than 14 tons (apart from plated 15and 16-tonners) and a three-axle more than 22 tons.
Despite these liberal standards the results were disappointing: 13 per cent of all vehicles sampled were operating above permitted weight limits. This figure represented 7 per cent of vehicles operating at over 10 tons on any axle but within gross limits and 6 per cent operating above the gross limit.
An analysis of the test weighing sample data enabled vehicles to be classified by the commodity carried. The table shows the percentage of vehicles overladen carrying specified commodities, the figure being broken down to show overladen axle or gross components.
Even with the possibilities of error, the analysis shows how overloading varies widely. Everyone knows of the severe operational problems in civil engineering and agricultural transport, but even so their performances are notably poor.
The significance of the gross overloading figures is that these vehicles must suffer a payload reduction to comply with permitted regulations. Axle overloading can be avoided, in theory, by better load distribution, although it is often difficult, if not impossible, in practice.
The data on overladen vehicles was analysed to see whether any significant differences existed between the type of vehicle operated and the bodywork carried. The vehicles were divided into rigid and articulated categories and bodywork was classified into flat, tipper and other categories, a division including pantechnicons, bulk tankers, cattle trucks, etc.
Interesting results
The results proved interesting. Vehicles with specialized bodywork did well in meeting weight regulations. Only 6 per cent of all the vehicles found to be overladen came from this category; 95 per cent of overladen articulated vehicles have their weight problems centred mainly on axle loadings and suffer no significant gross vehicle weight problems. And 66 per cent of the overloaded rigid vehicles were operated above gross vehicle limits. Therefore, though the risk of overloading an articulated vehicle can be reduced by better load distribution, payload must be reduced in two-thirds of the overloaded rigid vehicles.
When the data was analysed into axle groups, the two-axle flat and tipper and the three-axle articulated flat vehicle gave an inferior performance relative to their original distribution in the sample. These, then are the most suspect vehicles in relation to plating.
The 1968 Plating Regulations give each vehicle a specific gross weight limit and distribute this figure to give maximum permitted axle loadings. Therefore, if weighing equipment is accurate, it will be relatively simple to prove overloading. To indicate the size of the problem it was planned to analyse the weighing sheets and compare each vehicle's performance with its future permitted limits as published in the Standard List. Unfortunately, these were not available and it was agreed to compare the vehicle's performance with the manufacturer's recommended weights. (The plating regulations are based on the technical specification of the vehicle and this was the best alternative standard that could be applied.)
Poor figure
Using this yardstick it was calculated that the percentage of overladen vehicles rose from 13 to 19; allowing for the worst limits of error this is a poor figure. The poor 1967 performance of the two-axle vehicle worsens while that of the threeand four-axle classes shows no real increase and therefore an improvement in the share of overloading.
When the sample was analysed to discover the nature of the overloading it was found that the significant change in rigid vehicles involved an increase from 66 per cent to 77 per cent in gross overloading, suggesting that certain operators ignore manufacturers' recommended weights and load each vehicle towards the class limit of each particular vehicle. Naturally, if the Ministry choose to enforce the plating regulations strictly this practice will be readily detected.
An examination of the overladen articulated vehicles on the basis of the 1967 survey showed that the problem was solely overloading. The problem of gross overloading, though positive, was not significant.
Two-axle flat or tipping vehicles comprised 84 per cent of the rigid vehicles found to be overladen. A breakdown of this figure revealed that four-fifths was due to gross overloading. There was no significant increase in overladen axles.
Valuable feature
In the articulated class Mr. Harrison concludes there was no significant worsening of the 1967 position. The three-axle articulated vehicle was still the main offender, with what can only be surmised as weight distribution problems resulting in overladen axles.
One of the most valuable features of the survey was the opportunity afforded the inquiry team to interview road haulage operators, of all sizes. The fleet engineer of one prominent operator considered that one of the most difficult vehicles to load legally to its gross limit was the 24-ton, three-axle artic. This type of vehicle was investigated and of 186 outfits reviewed, 56 were overladen-30 per cent of the total. The faults were due almost entirely to bad load distribution with resultant axle overloading. The following are typical examples of trailer axle weights in this category: 13T 18C ,14T IC, 12T16C,13T6C,12T12C,12T7C,11T18C.
Problem rarely apparent
This axle overloading problem is rarely apparent to the driver because many of the tractors are plated at 26, 28 or 30 tons and can easily pull the overload. But this does not alter the safety problem posed by such units travelling at speed and inviting tyre or component failure on the trailer.
Conclusions:—
The relative ease with which vehicles with specialized bodywork met the weight regulations is noteworthy. Only 6 per cent of overloaded vehicles were in this category. Perhaps this suggests that most of the operators of such vehicles employ professional transport expertise! By inference, very few of the vehicles carrying civil engineering construction or agricultural products utilized specialized bodywork. The survey findings should encourage the body-building industry to develop specialized lightweight bodies for the trades that obviously need them.
Load distribution problems on articulated vehicles, particularly the 24-ton, three-axle types, will not be resolved by any number of Ministry of Transport surveys. Operators must accept responsibility for overloading offences, though their customers may be equally culpable. Portable weighing appliances and axle loading recording meters in drivers' cabs will help.
Straight talking
Straight talking between operators and customers is obviously necessary. Drivers must be given clear instructions as to procedure if it is obvious that a customer intends to overload a vehicle. Traffic managers must be specially careful to send only vehicles with adequate carrying capacity or platform size to collect loads; many traditional practices will have to go by the board. (It is perhaps significant that a trade union officer laid a recent complaint involving action by the Metropolitan Licensing Authority against two London hauliers and British Railways.) The effect of reduced loads on the earning capacities of rigid vehicles has been much discussed in recent months. There is reason to think that large numbers of operators have still not realized the hazards they will run if they continue to operate in traditional ways—the call by the Traders Road Transport Association for a full-scale Ministry of Transport publicity campaign suggests that ignorance of the requirements extends well beyond the ranks of professional road hauliers.