MAKING THE MODERN MOTOR ROAD.
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A Fivefold Growth of Traffic in a Few Years. The Essentials of a Modern Highway. What the British Nation Gets For £1 Per Head Per Annum.
By J. S. Killick, C.B.E.,
TN the introduction to his book, "The Road," Mr.' Hilaire Belloc states that we have arrived at a chief turning point in the history of the English highway. New instruments of locomotion, a greater volume of traffic, a greater weight in loads and vastly increased rapidity :j road travel, have between them brought us to an issue ; we must either face some very considerable and immediate change in the character of the road or suffer a serious and increasing handicap in ou'r rivalry with other nations through the strain and expense of our wornout system.
These words were written in 1924, but, before commenting upon the enormous efforts of our present-day road, engineers and the difficulties they have to con t,ad with in coping with modern traction, a few words concerning early road construction may perhaps not be out of place.
The man in the street travelling by motor over a good modern road will give little thought to the surface which permits his vehicle to travel so quickly and so comfortably, and it is only when driving along a disintegrated stretch that curi osity seems to be moused and the irritating series of jolts and bumps jerks out the question " Who made this road?" Following this one line of thought, back through the centurie. the question arises—" Who constructed the first road? "—a somewhat difficult question to answer.
An accepted theory, however, is that tracks blazed by our Neolithic forefathers upon the lines or tracks previously made by animals were our first endeavour. Succeeding generations deviated from the original lines of track sufficiently to take ad vantage of more stable ground, always having an eye to the defence of their camp and the provision of water. Probably, even in those days, our early progenitors, clad in woaii or less, com plained of the lack of foresight displayed in the alignment of their tracks. Whilst perhaps the road-hog was then unknown, we laay be sure that the condition of the tracks provided, even in those far,-off days, a fruitful source of complaint.
Whilst there is some evidence that the coastal tribes of what is known as England had made roads and causeways prior to the arrival of the Roman conqueror, there is proof that, in other countries, the necessity for and construction of roads had made greater progress. To give but one instance, as early as 4,000 B.C., Herodotus tells us that King Cheops built a great stone road, the construc tion of which must have been massive, for over this road were hauled the materials that went to the building of the Egyptian Pyramids, which were to immortalise his name.
We usually attribute to the Romans the achievement of first building roads capable of bearing transport, their efforts being primarily caused by military necessity, and one:of the earliest records shows that they built a paved road about the year 170 B.C.
Of special idterest to us are the remnants of the Roman roads in this country. The very earliest history of roads is necessarily a matter for conjecture in the absence of definite records, but it has been stated that at least one English highway, viz., the Pilgrims' Way, originated in the Iron Age, or even earlier, and the leknield Way, so essentially Roman in its asso ciations for us, was probably a very definitely existing highway before it was reconstructed as a military road. Other main highways of the Romans here appear to have been the Watling Street from Dover to Chester and York, Ermin Street from _London to Lincoln, and the Fosse Way, which met Watling Street in Leicestershire and ran through Bath to London. There were, of course, many others, too numerous to mention.
It is interesting, therefore, to know that not or..ly was the road perhaps the oldest of the factors in the evolution of man, and that roads, quite as much as geographical physical conditions, determined the political development of peoples and left their mark on history, but that, right up to the first 'half of the 19th century, the road was practically the only means of land communication open to man. The advent of railways provided a more rapid means of transport, and developed a steadily increasing volume of traffic resuiting from improvement in trade.
It is well known that, with the construction of railways, our roads fell into disrepair, and for some time it was not realized that roads were as essential to railways as water is to the steam engine.
At the commencement of the 20th century a new factor came into play which gave back to the road much of its earlier importance. Those responsible at that time for highway maintenance had satisfied, reasonably well, the requiremeiits of the travelling public, but, with the advent of the motor, new problems arise in the shape of thedrist nuisance and the rapid disintegration of water-bound surfaces which had proved satisfactory for many years.
The rapid development of mechanical road transport threw a greatly increased burden upon our roads—a burden, in fact, greater than they could bear. The surfaces and even the foundations of the existing macadam roads were unable to stand up to the new type of traffic, which subjected them to the much heavier impacts, due not only to greater weights but to increased speeds. Fortunately, palliatives were found which minimized the dust trouble and which, at the same time, diminished the disintegrating effect of the new form of traffic. Better roads begat more traffic, until, to-day, our country roads carry greater traffic than many city streets a few years ago. If statistics were not wearying, innumerable instances could be given to prove that traffic has increased as much as fivefold in the past decade.
Now, what has been done to meet this large increase? The highway authorities of the country, exceeding 2;300 in number, have made strenuous efforts, and their local financial resources have been strained to the limit, but, with assistance from the revenue derived from the taxation of mechanically propelled vehicles, "much has been done, although there is still much to do.
Our old but picturesque roads % are admittedly insufficient if motoring either for business or pleasure is to be worth while or economical. There is a limit, however, to the money which can be found for road improvement and maintenance, and the problem is to decide how the funds available can be allocated to give the best results. The present policy of the Ministry of Transport is to encourage by financial help the widening and improvement of our existing trunk roads and the construction of new roads so far as funds permit. This appears to be sound, and surely all will admit that our roads have shown vast improvement since tie war.
What are the Essentials in a Modern Highway ?
N.ow, as motorists or road users, what do we look for in a road? What are the essentials in a modern highway? I suggest the following :—
There should be sufficient width between fences to allow• of two carriageways, one for up and one for clown traffic. In the ease of new roads, a minimum widtIV'ef 100 ft. Is suggested. Each carriageway should be capable of carrying two lines of traffic with ample footpath accommodation. Sewers, water, gas, electric light, etc., should not be placed under the carriageway or footpath, but should be placed between the carriagOway and footpath to allow of easy access.
Good alignment is an essential.
Easy gradients are desirable.
Great care should be exercised in the planning of junctions and cross-roads.
• Efficient drainage is necessary if the road is to be durable. A strong foundation is vital, and last, but not least, a durable surface must be provided.
One word regarding foundations. The point is often forgotten that nature has provided the foundations for everything that nadn builds, in the shape of the earth's crust, but this crust inevitably suffers from local "[kin diseases" in the shape of marshes and patches of unstable ground. These have to be dealt with, partly by removal and by the substitution of a superficial layer not subject to waterlogging. Much work of this character was carried out by our predecessors, working on principles laid down by Telford and Macadam, whose names have become household words in every country of the world.
Why Main Road Traffic Should Have 'Right of Way.
There are millions of pounds sterling of accumulated value in our roads to-day, which only need to be protected from the elements and the disintegrating action of traffic to give their worth. The road engineer will tell us that, if sufficient money be forthcoming, his greatest difficulties will be to plan the intersecting junctions with cross-roads and provide a surface which will be durable and reasonably inexpensive.
With regard to the junctions of roads, I am definitely of the opinion that, until new legislation is passed giving prior right of travel to those on main roads and compelling those entering such from intersecting roads definitely to stop at the junction, se long will the appalling accidents which we read of every day continue. This system has c38
been tried, and if only powers can be obtained to enforce this, many lives will be saved.
A modern road surface, if it is to withstand present-day traffic, must be impervious to moisture, and must have a surface which calls for low tractive effort. It should be remembered that the greater the co-efficient of friction between the tyre of the vehicle and the road surface, the greater are the road-holding properties of the vehicle, and it follows, therefore, that, if the coefficient of friction is great, the wear and tear of the road surface is correspondingly great. Our road engineers have, therefore, applied their knowledge and experience to produce a road surface which in practice proves to be impervious to moisture, dustless, and, consequently, sanitary, and one which will last as long as possible, with low initial cost and subsequent maintenance charges.
Lessons can often be learned by those prepared to learn from nature. Most of us have seen stretches of sand on the coast which, after the tide has receded; will allow of comparatively heavy vehicles to pass over without leaving a mark. This is due to the particles of sand which, varying in size, fall naturally into their proper places, thus forming a dense mass, and one capable of withstanding distortion by traffic.
One of the great difficulties in road construction is to find a surfacing material which containsas small a percentage of voids or air pockets as possible, for it is found in practice that, if the percentage be excessive, the surface will crush under traffic and be a failure.
The most satisfactory modern road is built having regard to these principles. Stones and sands of sizes predetermined to eliminate voids are mixed together and held in position with an elastic, tenacious and water-proofing material. It is proverbial that nature provides both bane and antidote, and it is a curious coincidence that zrude petroleum which supplies the petrol which indirectly causes damage to roads supplies also the substance, namely, bitumen, which is so largely used to-day to prevent such damage.
The Construction of the Modern Road.
2xamples of roads built on the foregoing principles are the new arteries of traffic in the neigh bourhood of the metropolis. This is by no ;Deans the first time that such surfaces have been built, but they are the ultimate scientific development of similar types of surfaces laid in many parts of the world for the past 50 years. Probably the Ministry of Transport decided upon this class of road because they were fully cognizant of the success of sothewhat similar materials upon some of the heaviest trafficked roads for years past in British and foreign cities.
It is general knowledge that the city street carrying the greatest number of units of traffic per day of any road in the world is Fifth Avenue, New York. The surfacing there has an average life of 22 years, and is of a similar nature to that which has been largely employed on our new
arterial roads. Naturally,the lay mind would assume that, to produce these results; a heavy and massive structure is required, but, as a matter of fact, the thickness of The modern road surface capable of resisting the wear of intense traffic seldom exceeds 3 ins., provided always that the preparatory work, such as drainage and foundations, has been carried out on sound civil engineering principles. •
Foreigners from all over the world speak loudly in praise of our excellent roads. Americans who visit this country state, without exception, that our roads are infinitely better, taken as a whole, than those in the States, and praise from such a source is praise indeed.