Pie-Crust Highways.
Page 17
If you've noticed an error in this article please click here to report it so we can fix it.
A Plea for Uniformity in Road Construction and Maintenance.
A public highway is, presumably, intended to be a weightsustaining structure. And, that being so, the primary object of its design is ostensibly an economical carrying capacity for a legitimate traffic burden. The best road, therefore, should naturally be that which results in an economy of upkeep having strict reference to an allied economy in user. Hitherto, however, considerations of tractive efficiency have, unfortunately, had no serious attention from highway authorities to whom, in the past, the cost of moving loads over the road surfaces within their jurisdiction has been of no practical interest whatever. The general tendency, indeed, has been to penalise rather than to encourage user, though for this the unfair highway rating methods which prevail have doubtless afforded some reasonable exuse. Up Up to the present it has contented highway authorities that their roads should simply bear, without serious dislocation of surface, and quite regardless of the animal or mechanical effort expended, the ordinary traffic of the district. And when, by the opening-up of new local enterprises, or the erection of new edifices, the road burden has become permanently or temporarily augmented, it has immediately been sought to enforce the pains and penalties of " extraordinary traffic." That increased volume of business, therefore, which would cause a railway or a canal company to rejoice, has so far plunged our highway authorities into despair.
A highway is about the only existing artificial device not designed for definite services. And yet an examination of The bye-laws of various English County Councils, regulat.ing horse-drawn traffic, in some degree proves that they are not intended for indefinite service. The striking feature of these bye-laws is their utterly hopeless empiricism and inconsistency. The difficulty is to discover any principle upon which they can have been formulated. One may, for example, set out from Northumberland with a load which is permissible in that county, but, on entering Durham, the same load, will become absolutely illegal ! In the case of four-wheeled vehicles, one may, in Northumberland, carry up to 9 tons on oin. tyres, but in Durham and Yorkshire only 7i tons, whilst in Westmoreland one must restrict the load to 41 tons in summer, or only 41 tons in winter. In sonic counties the heaviest loads per inch of wheel breadth are allowed on the narrowest, and in others on the widest, tyres. And, so far as the ordinary singlehorse two-wheeled cart traffic is concerned, it is not a mere allegation to say that the highway authorities are themselves the most deliberate offenders against their own enactments! Their road-metal carting contractors are freely allowed to convey loads of 3ocwt. or more in vehicles only supposed to carry one ton, the wretched horses incidentally suffering as well as the roads.
The bye-laws are instructive as indicating the intention, however inconsistent, to establish standards of road-carrying capacity. If the single-horse cart or lorry is taken as the commonest form of typical weight-carrying vehicle, a standard of 6cwt. per inch of tyre is found to be a very general average, but it is somewhat remarkable to observe that there is no steam roller at present operating on British roadways which has appreciably more than 3cwt. on each inch of its wheel breadth. This means simply that the greatest existing test load of our British road makers is only about so per cent. of their usual working load, a circumstance which surely requires no comment.
The steam rolling of any road is important evidence which has a very material bearing upon self-propelled traffic. A highway that will support a steam roller weighing to or 13 tons must be regarded as a solid mass capable of taking very big total weights, and only likely to be affected by too great intensities of loads. It cannot be regarded as a hollow crust determinable by total loads—irrespective of the wheel breadths upon which they are carried. All hostility exhibited generally by highway surveyors to self-propelled traffic by reason of total weights alone is utterly inconsistent. The veriest tyro will perceive that, with equal loads per inch, a very narrow wheel will cut into and in time destroy a road which a broad wheel will simply consolidate; the latter approximates to the character of the roller. If one form of traffic ought to be preferred upon its merits before another, it is the broad-wheeled, self-propelled commercial motor, especially when the avoidance of damage by horses' feet is included in its favour. Whatever British roads ought to be, they are in reality, to a far too large extent, akin to suspended or floating structures, and so long as our highway 'authorities are permitted, with impunity, to harass modern forms of user—owing to the consequences of road-bed insolidity and decades of apathy and neglect—the evils are likely to continue.
Some highway authorities freely recognise that self-propelled traffic has come to stay, and that they can no longer play with their responsibilities. So far, however, it is clear that they have not approached the root of their troubles. If there is one thing about British highways still more palpablyneglected and more conducive to tractive inefficiency than another, it is the matter of drainage and surface contour. It is infinitely more important that a road should be well drained than that it should be thickly metalled, and no amount of surface metalling will suffice if made into an absorbent hotch-potch with roadside scrapings or turf. If a road surface is to resist traffic wear and the ravages of frost, its material must be reasonably waterproof and its contour such as will throw off the rainfall. Yet, in spite of these admitted conditions, there are to-day hundreds of miles of roadways in Great Britain whose cross-surface sections are concave instead of convex, and which have no semblance whatever of side ditches. The purely agricultural and other long-suffering users of such roads have, until recently, taken them as a matter of course, content so long as their horses and vehicles were not bogged. But now that British roads have become vital factors in the general carrying trade of the country, it is intolerable that their construction and maintenance should not immediately be put upon a proper engineering basis having reference to a strictly dynamometric efficiency. Further, within definite limitations of loads per inch of wheel breadth, there should be no impediment whatever to their user. The present law of extraordinary traffic is a scandal to a civilised and commercial nation. Its two-edged application to ordinary loads carried in extraordinary quantities, and to ordinary quantities conveyed in extraordinary loads, no matter that the wheel breadth in either case is perfectly legitimate, is nothing less than an anachronism. There must, henceforward, be a community of interest between the road maker and the road user. It is unquestionable that the least expensive road to maintain is the one which offers the least resistance to wheeled traffic, and which has the least capacity for admitting or retaining water in suspension. Joite MORRISON (Newcastle-on-Tyne).