The thickness of such road is immaterial, as to its strength for carrying weight; this object is already obtained by providing a dry surface, over which the road is to be placed as a covering, or roof, to preserve it in that state: experience having shewn, that if water passes through a road, and fill the native soil, the road, whatever may be its thickness, loses its support, and goes to pieces.
In consequence of an alteration in the line of the turnpike road, near Rownham Ferry, in the parish of Ashton, near Bristol, it has been necessary to remove the old road. This road was lifted and relaid very skilfully in 1816; since which time it has been in contemplation to change the line, and consequently, it has been suffered to wear very thin. At present it is not above three inches thick in most places, and in none more than four: yet on removing the road it was found, that no water had penetrated, nor had the frost affected it during all the late winter; and the natural earth beneath the road was found perfectly dry.
Several new roads have been constructed an this principle within the last three years. Part of the great north road from London by Hoddesdon in Hertfordshire—two pieces of road on Durdham Down, and at Rownham Ferry, near Bristol—with several private roads, in the eastern part of Sussex.
None of those roads exceed six inches in thickness, and although that on the great north road is subjected to a very heavy traffic, (being only fifteen miles distant from London) it has not given way, nor was it affected by the late severe winter; when the roads between that and London became impassable, by breaking up to the bottom, and the mails and other coaches were obliged to reach London by circuitous routes. It is worthy of observation, that these bad roads cost more money per mile for their annual repair, than the original making of this useful new road.
Improvement of roads, upon the principle I have endeavoured to explain, has been rapidly extended during the last four years. It has been carried into effect, on various roads, and with every variety of material, in seventeen different counties. These roads being so constructed as to exclude water, consequently none of them broke up during the late severe winter; there was no interruption to travelling, nor any additional expense by the Post-office in conveying the mails over them, to the extent of upwards of one thousand miles of road.
Many new roads, and to a considerable extent, are projected for the ensuing season. Some of them are to be assisted by grants or loans from government, and it will be a great saving of property, and enable government to extend their assistance more effectually, if these roads be made in the most approved and economical manner.
The unnecessary expense attending the making of new roads in the manner hitherto practised, is one great cause of the present heavy debt upon the road trusts of the kingdom. The principal part of the large sums originally borrowed, have been sunk in the useless, and in my opinion, mischievous preparation, of a foundation. This debt presses heavily on the funds of all the roads in England, and, in many cases, absorbs almost their whole revenue in payment of interest. In Scotland this pressure is still more heavily felt: indeed it is not of uncommon occurrence in that country, for creditors to lose both principal and interest of their loans to roads.
This causes not only a great and unnecessary loss in the first instance, and a deficiency of means for ordinary repair, and maintenance of the roads, but it also discourages the formation of new roads. Were a better and more economical system generally adopted and acted upon, many great additions and improvements of the communications of the country would take place, from which, at present, the landholders are deterred, by fear of the extent of the expense, and the difficulty of obtaining loans of money.
The measure of substituting pavements, for convenient and useful roads, is a kind of desperate remedy, to which ignorance has had recourse. The badness, or scarcity of materials, cannot be considered a reasonable excuse; because the same quantity of stone required for paving, is fully sufficient to make an excellent road any where: and it must be evident, that road materials of the best quality may be procured at less cost than paving stone.
The very bad quality of the gravel round London, combined with want of skill and exertion, either to obviate its defects, or to procure a better material, has induced several of the small trusts, leading from that city, to have recourse to the plan of paving their roads, as far as their means will admit. Instead of applying their ample funds to obtain good materials for the roads, they have imported stone from Scotland, and have paved their roads, at an expense ten times greater than that of the excellent roads lately made on some of the adjoining trusts. Very few of these pavements have been so laid as to keep in good order for any length of time; so that a very heavy expense has been incurred without any beneficial result, and it is to be lamented that this wasteful and ineffectual mode is upon the increase in the neighbourhood of London.