Road Widenings and Motor Roads.
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By John A. Brodie, Wh.Sc., hi.Inst.C.E.,
I desire to thank you very heartily for the honour you have done me in electing me to the honourable position of President of this important Association for the year. I assure you that I appreciate very highly this honour, coming as it does from the members of that branch of the civil engineering profession with which I have been connected for many years.
It seems to me that the city of Liverpool is an appropriate centre in which to discuss we two suejects which are now occupying so prominent a place in municipal and public opinion—viz., the laying-out of towns and the requirements or unproved access by means of roads, as during the past ten years no less than 22,000 houses have been built within the limits of the present city, representing a population of, say, 120,000 persons, and is a city which is, up to the present time, and is likely to be even more so in the future, dependent upon its means of access, more than any town I. know of. The central streets were originally narrow, and, though it cannot be truthfully said that tney are yet too wide, it is recorded that some of them have already been widened twice, if not three times, at great expense. The boundaries have been extended from time to time and the populous districts outside the city have been absorbed. The general policy in this, as in other towns in this country, has therefore been to leave the development of building areas on the outskirts in the hands of small local authorities, and the results —particularly as regards the main lines of communication— have been, as might have been expected, the construction of roads which served for purely local traffic, but are altogether too narrow to form satisfactory outlets from a great city. Although no needless expenditure has been incurred on street widenings and improvements, yet the outlay on bringing up most of the main thoroughfares to a width sufficient to allow for the lines of tramways has been very considerable, and during the past ten years alone the expenditure on street widenings has amounted to about 4:1,250,000. Notwithstanding the heavy cost which has been incurred in connection with street widenings, it has been the policy for some years past to widen main lines of communication to a minimum of 6o feet, and in some recent cases this width has been exceeded.
Liverpool's Special Powers.
Most of these street widenings have been carried out under the powers acquired by the Improvement Act of 1867, the procedure under which has many advantages over that of the Public Health Act of 1875, as the authority has power to lix a line of building and also to purchase so much of the land as they may consider to be required for street widening purposes out of funds provided under the Act, and without reference to the Local Government Board. It has, however, in some cases where buildings exist, been necessary to proceed by way of a special Act of Parliament or by Provisional Order. Owing to the expense and difficultyin arranging' with owners of property fronting main roads, in the year 1902 power was obtained to set back the line of buildingon each side of the centre line of any new street to a distance of 40 feet ; also to vary the widths of carriageways and footways, and decide upon the directIon or position of any new street ; and also require the rounding off or splaying to the height of the first storey or full height of new buildings at thc corner of two streets. These powers have made it possible to arrange with the owners of large properties about to be developed as building areas for the construction of wide streets through their property, and a considerable length of wide streets has already been oonstructed through unbuilt upon areas in the outskirts. It has been the policy in these cases to assist landowners by constructing streets through lands some little time in advance of the actual commencement of building operations, and the results both to the authority and to the landowners have been most satisfactory. In these cases the landowners have undertaken to pay for the construction of street works in compliance with the mini
mum requirements of the by-laws relating to new streets about to be laid out, and have in addition given up a strip of land 24 feet wide, making in all a width of Oo feet. Where the owners have agreed to this policy, and to the lines of street being laid down in a direction •advantageous to the public, the authority has undertaken to purchase from the landowners strips ot land 24 feet wide at the average value of the estate taken as a whole, thus making the width of street 84 feet. In addition to this, an attempt has been made to purchase a further 24 feet width of land with the object of providing for the laying of tramway lines in the centre of the thoroughfare in such a position and in such a manner as to enable the lines to be fenced off in lengths between cross streets, so that the average speed of the tramcar might be very much accelerated. Under the complete arrangement a street io8 feet wide between boundary walls will be provided, and the cost of such a street over and above the cost of a street of the minimum width required by the by-laws would be apportioned approximately as follows ;— One third to the landowner ; One third to the street authority ; and One third to the tramway undertaking; the landowner getting the advantage of a magnificent thoroughfare through his estate ; the street authority obtaining a wide thoroughfare at—in many cases—one tenth the cost of the widening of parallel thoroughfares already built up which would otherwise have been necessary, and the tramway authority obtaining the advantage of quick transit, and also the additional advantage of a cheapened construction, as in this ease it would not be necessary to provide any expensive form of street surface between the rails.
Control of "Developing" Estates Necessary.
At the present time local authorities have very little control over the laying-out of streets in such areas except by arrangement with the landowner, and cases often arise in which the landowners can comply with the by-laws and yet set the authority at defiance. Some method is required by which the authority should have the power to disapprove of such plans and to prevent, under a penalty, the construction of streets otherwise than in accordance with such conditions as they may approve in the matter of direction, width, and levels of roads. In cases of small and irregular areas, failing agreement between the respective owners as to the adjustment of boundaries, powers might well be given to the local authority to adjust boundaries, of course after hearing evidence on behalf of the parties interested. The question of the improvement, in the laying-out of areas adjoining the boundaries of an urban district is a difficult. one, as in the absence of statutory powers it would be difficult to provide for the satisfactory. laying out of building areas, and for the provision of wide roads, but even if Parliament should not be inclined to grant over-riding powers to the larger towns there. does not seem to be much objection as a minimum to the smaller authorities havingthe right to adopt for application to their districts any sections, of Acts acquired by the larger authorities.
Improved Main Roads Wanted.
The question of the improvement of main roads is now undoubtedly receiving--and properly so—a great deal of attention, both on the part of local authorities and the public, arid it is a difficult matter to say what the future 1-1(N:116nm-tents in the way of main noads may be, SO ninch depending upon the possible solution of still unsolved problems. At present, . however, we have a distinct demand foe a smooth, durable, economical, and dustless surface to meet the requirements of the lighter. motor traffic, and it is also not unlikely that a very much larger amount of heavy traffic will have to be provided .for, as improvements ia connection with machines for heavy haulage, though slow, are making distinct progress. Another possibility exists In the formation of trains, something after the style of the road train exhibited at the last Olympia Exhibition. Taking broad view of the question, it appears not unlikely that in the near future the roads of this country are again to become most important systems of intercommunication both for the purposes of light traffic and heavy traffic between communities, and though it may be argued that the widening of existing roads will meet all probable requirements, it appears much more likely that in many cases provision will have to be made for straight and wide thoroughfares between populous centres. We must all admit that our .roads—particularly in the neighbourhood of large towns— are capable of great improvement. Many of thorn were never designed or intended for through traffic purposes, and,' apart from their want of directness between points, have corners, cross roads, and other details which to-day are .dangerous to the ordinary users and should be dealt with. It is to be hoped that, where improvements are necessary, .a far-seeing view will be taken of the requirements, and that wherever it is economically possible, new roads of a
• suitable character to meet the requirements of modern traffic will be constructed in preference to the widening and • straightening of existing roads, even though the latter course may for the present appear to be the more economical.
Proposed Steelc ve redTracks.
The increasing use of heavy vehicles for the conveyance -of goods along the ordinary roads is in many districts causing road engineers a good deal of anxiety on account of the damage done to their road surfaces, and it appears not unlikely that the provision of satisfactory road surfaces for the conveyance of mechandise may presently form a very important portion of the duties of the municipal and county engineer. Where sufficient traffic of a heavy character is .continuously passing over a line of road to pay for the construction of a steel surface, it is hardly likely that a stone • surface will be found seriously to compete with it, but there will still remain many roads on which the traffic will be so 'mixed, in character that a surface in which stone is the 'principal ingredient will probably meet all requirements.
Some ten years ago it was very confidently stated that electric tramways, especially on the overhead system, could not possibly come into general use in this country, and could never compete with fast trains on our local railways. Time has, however, demonstrated that tramways are more than able to hold their own in certain classes of traffic, and that the introduction of cheap fares consequent on the small -capital cost of construction, which, in the case of 'tramways, -is probably not a tithe of the capital sunk in connection with 'parallel railways, is one of the principal elements in connection with the success of the tramway services. At the present time tramways exist in our main thoroughfares, and in some cases in this city the steel surfaces of these tramways are conveying a tonnage in excess of the tonnage conveyed on a single track of the principal main line of railway in the country, and without any very serious interference with the ordinary users of the street surface. When the lessons which may be learnt from a close comparison of the two systems are fully understood, and especially if a -surface is provided suitable for all classes of existing vehicles, the day for the conveyance of merchandise in large quantities -over public roads will probably have arrived, I may say that, as the result of my study of special requirements for -traffic purposes in connection with main roads, I have for many years been of opinion that ultimately it will be necessary in special cases to grapple with the question of cheap transfer of goods on public roads, and when this problem is faced it will In my opinion be solved by the construction of wide thoroughfares having a portion of the surface laid in steel, in such a form and so arranged as to provide for the passage of railway wagons, tramway vehicles, motor -trains,. and fast-travelling vehicles of any type. This is, of 'course, no new suggestion, as in this city we have in Mr, Alfred Holt a distinguished exponent of this theory, who has
for many years past consistently and persistently advocated the use of a " plateway " for goods traffic between the seaboard and the manufacturing districts.
Macadam out of Date.
' With regard to road construction and the materials used for roads, we are told by the non-technical Press that the
road r of the present time know practically nothing about e requirements of read construction necessitated by the advent of the motorcar. As many of us are motorists of considerable experience, we could, with some truth, retort that motorcars are in many ways quite as imperfect and as costly to maintain as the roads over which tney run. We are told that roads should he constructed entirely on the lines laid down by Macadam and Telford, and it cannot be doubted that roads so constructed have fairly met the conditions for moderate traffic up to the present time. It is, however, well known that the macadam road is entirely unsuitable for roads carrying really heavy traffic, and my experience in providing and maintaining street surfaces to carry the heaviest traffic which I know to exist anywhere— viz., that along the line of docks in the city of Liverpool, where the averagetwo-horse load on four wheels amounts to 7 to so tons, and where a common load behind a traction engine, I am assured by traction engine users themselves, may be taken as 35 tons, and where exceptional loads up to MOO tons on four wheels mar at any time be expected— leads me to think that the satisfactory and really economical surface for even light traffic is quite as likely to be found where the surface is so arranged as to entirely prevent any rolling or grinding action or motion of any sort amongst the materials forming it, as in the macadam type of construction, in which time surface materials are so arranged as to be liable to motion under any passing load.
A Twenty-five Years' Life.
Of course, the other conditions for success in such street• construction are very important—viz. :— I. A thoroughly satisfactory foundation, 2. A proper layer of efficient bedding for the stones, on which they are firmly rammed, preventing any movement or further compression.
3. The use of a hard shingle in the joints.
4. A perfectly impermeable jointing material in the nature of a plastic mixture of pitch, sand, and oil.
• 5. A hard, durable, and non-slippery stone for the wear .; ing surface. 'Our experience with medium traffic shows that the annual post of maintenance of a street is practically nil over a life at present extending up to twenty-five years, and though I cannot at present point to any form of such construction which is entirely suitable to replace the ordinary macadam road, I venture to think that time and thought expended on the improved application of those principles to meet the requirements of lighter traffic roads will ultimately result in satisfactory solutions of the problem.
Points about Tar.
In coal tar and its products we have a material which appears likely to be largely used for jointing or filling up interstices in the materials used for road construction, and though owing to its variable nature it is not generally understood, many road engineers have done very satisfactory work with it, in most cases, however, using limestone slag or other material of a comparatively porous nature. When coal tar has been applied to the hardest materials, now so generally preferred for road-carrying traffic, the results have often been unsatisfactory owing, it would appear, to the absence of porosity in the stone used. When dry, hard, and non-porous stones are preferred, great attention might, I think, advantageously be paid to the preparation and blending of pitch and the coal-tar Os_
(To be continued.)