Memorandum on Route Numbering

(This document can be found in MT 39/241).

MEMORANDUM ON ROUTE NUMBERING

A commencement of this Scheme was made last year, when England and Wales was divided into six zones by utilizing six main trunk routes as boundary limits, and it was then decided that all routes originating in a zone, working clockwise from left to right, should be given numbers commencing with that zone number, irrespective of the number of zones through which they were carried, or of the zone in which the other terminal was situated. Adopting this method, two figure numerals were assigned to the 10 routes of prior importance in that particular zone.

Since the completion of the recent revision of Classification, the possibility of the extension of this scheme to include all roads in Classes I and II has been examined, with the following results, which are now submitted for approval:

1ST CLASS ROADS

It was expected that three figure numbers would suffice for the numbering of all the routes in each zone and that the smaller links and short lengths in the more congested zones would alone bear four figure numbers. Upon this assumption, and having chosen roads in each zone in London, which could readily claim to rank as of arterial rather than local importance, the roads have been connected into particular routes, which are either already well known or which appear to be sufficiently reasonably to warrant such connection.

In executing this, a principle was adopted that it was inadvisable to accept a continuous route to two distinct roads or lengths of road which could only be joined by a road already taken as part of another route, where the joint length was more than about two miles. This has increased the number of separate routes, but is regarded as a precaution essential to the success of the scheme. In this connection, the question of sign posting the joint length has also been considered and it is thought that the indication of the route upon the sign post which includes the name of the next town or village will be a sufficient guide to normal cases. In other instances however e.g. in towns, etc., it may be found necessary to affix a special notice plate to the post giving an explanation of the route to be followed in order to reach the continuation of the numbered route which has been temporarily interrupted.

The numbers have been assigned to the selected routes clockwise in a series of concentric circles, with London as the centre, somewhat modified however,in areas more remote from London, thus ensuring that routes nearer the "hub" bear the earlier numbers and that the numbers allotted to routes originating in any particular area are in close sequence.

The application of this scheme to Zone 2 was found quite practicable, and in Zone 3 it has also been accomplished. The remaining zones, however, provided more important routes than the 100 numbers available. It was therefore found necessary to select from these routes the 100 which could be considered without doubt of greater importance than the rest, and to these, following the same system outlined above, were allotted the three figure numbers available.

Four figure numbers were then given to the remaining roads and links as they "rose" in again traversing the whole area commencing from the centre. (In Zone 4, it was found that if all roads other than links, were numbered in sequence, three figure numbers would have been exhausted almost before any roads in Wales had been dealt with).

The roads in London which had not been considered of sufficient importance to warrant the use of three figure numbers will be given four figure numbers, corresponding to the zone in which they fall and it is proposed that they shall all bear numbers in a similar hundred, e.g. 1,300, 2,300, 3,300 etc. The particular hundred will be decided when the highest four figure number used outside London, in any of the zones, has been discovered: For instance, if Zone 4 has appropriated the greatest number and the last one used is 4278, it is suggested that all unused numbers in each zone up to - 399 inclusive shall be kept for future use outside London, and the London roads will then receive numbers 1,400, 2,400 onwards etc.

2nd CLASS ROADS

These roads by virtue of their general character of links rather than routes or communications, present a somewhat different preposition, they cannot readily be connected into different routes and being shorter in average length are in greater numbers.

If was also thought that it could not reasonably be argued that greater length was a necessary proof of mere importance. Instances can be found of roads near congested areas under a mile in length, posessing certainly equal claims to importance with those of ten or 15 miles in other areas.

The allocation of single or two digit numbers to any particular road in the 2nd Class would therefore be a misnomer, especially when the principle of prior importance has already been clearly indicated in the case of 1st Class Roads.

It is therefore suggested:-

1. That the single and two digit numbers should not be used in the 2nd Class. (This will only mean 11 numbers in each zone).
2. That the first 50 three figure numbers in each zone should be reserved for roads in London. (This it is anticipated will also provide a sufficient margin for some years).
3. That all the remaining roads shall be numbered in sequence as they "rise", whether they consist of short communicating links or stretches of greater length.

In carrying this out, it is expected that the three figure numbers will be used on roads almost within the Greater London area, and therefore it would seem advantageous that the last ten numbers from -90 to -99 in each zone should be kept as a reserve for future 2nd Class Roads in that area. The remainder of the roads working outwards from London will then receive four figure numbers in due sequence. It is not considered practicable or necessary to attempt to reserve any further numbers in any particular area for changes due to subsequent revision, and numbers following the last number used will be allotted to these roads when the necessity arises.

Ministry of Transport

28th June, 1922.