 |  |
| Publications |
| Home | Press | Publications | What We Do | Who We Are | Search | Site Map | Contacts | Links | ||||
| | |||
| Publications > Transport | ||||
< Previous | Contents | Next >
1. Introduction
1.1 This chapter provides information about public road lengths by local authority, class, type and speed limit. There are also statistics on the condition of road surfaces (referred to as "pavements" by engineers) and the amount of new roads which have been constructed, re-surfaced, strengthened or surface dressed.
1.2 It should be noted that there may occasionally be unusual year to year changes in the reported road lengths due to one or more of the data providers starting to use Geographical Information Systems (GIS) to calculate road lengths - see section 3.4.
2. Main Points
2.1 There were almost 53,900 kilometres of public road in Scotland at 1 April 2000. The trunk road network accounted for 6% of the total. Other (non-trunk) A roads represented 14% of the total. Minor roads (B and C roads, and unclassified roads) accounted for the remaining 80% of roads. (Table 5.1)
2.2 Over a quarter of the total trunk road network, and about one-seventh of the Scottish road network, is within the area of the Highland Council. Around 10% of the Scottish road network is within the Aberdeenshire Council area and a further 8% is within the Dumfries and Galloway Council area. (Table 5.2)
2.3 Trunk road area constructed/opened in 1999-00 was the lowest in 10 years and was 43% less than the previous year. However, there were increases in the amounts of trunk road that were reconstructed (up 78%), surface dressed (up by 68%) and strengthened (up 24%) compared with the previous year. (Table 5.3)
2.4 The new trunk road constructed in 1999-00 was in the Forth, Central and South West areas. (Table 5.4)
3. Notes and Definitions
3.1 The trunk road network is the responsibility of Scottish Ministers, and comprises all motorways and some of the main A roads (local councils are responsible for non-trunk roads). The Government’s view, when it reviewed the trunk road network in 1994, was that the trunk road network should:
a. provide the road user with a coherent and continuous
system of routes which serve destinations of importance to industry, commerce,
agriculture and tourism;
b. define nationally important routes which will be developed in line
with strategic national transport demands; and
c. ensure that those roads which are of predominately local importance
are managed locally.
3.2 On 1st April 1996, local government was reorganised, and the 32 present Councils replaced the former Regions, Districts and Island Areas. At the same time, changes were made to the trunk road network: about 580 km of former non-trunk roads became trunk roads, and over 340 km of former trunk roads ceased to be trunk roads.
3.3 Major roads: Motorways and A roads.
3.4 Changes in road lengths: Where there has been a change to the use of a Geographical Information System (GIS) as the basis of the road lengths figures, they may differ significantly from those for the previous year (see section 4.3). This may be why some local authorities have differences of 20-40 kilometres between their figures for 1999 (published last year) and their figures for 2000 (published here). It is certainly the reason why the length of unclassified roads reported by Falkirk Council increased from 400 km in 1999 to 572 km in 2000.
3.5 Operating Units: in 1999-2000, for the purpose of maintenance, the trunk road network was sub-divided into 8 operating units. On the 3 Premium Units, covering Tay, Forth and Clyde, and comprising mainly the motorways and major inter-urban dual carriageway routes, Operating Companies provided a complete management and maintenance service. On the 5 All Purpose Units covering the North West, North East, Central, South East and South West and comprising primarily rural single carriageway routes, Management Agents were appointed to undertake management and professional services, and to co-ordinate the work of the local Councils who provided the front-line routine and winter maintenance service. Details of the areas that were covered by these Units can be found in the Annex. New arrangements were introduced with effect from 1 April 2001.
3.6 Areas of trunk road constructed, resurfaced, etc: in tables 5.3 and 5.4 the area of road resurfaced, strengthened, etc are expressed as ‘million square metres’. The reason for this is that the data represents the aggregate value of the area of work undertaken on the whole network including single carriageway roads, three or more lane single carriageways, dual two lane roads and dual three or more lane roads including motorways. It also includes work done on slip roads and junction areas. In addition, work is not always undertaken on the whole carriageway width at specific sites. As a result, it is not possible to say what the total lengths of trunk road resurfaced etc were for each year. However, by assuming a standard lane width of 3.5 metres, an equivalent road lane length has been estimated, in order to provide figures which, to the user of this publication, may be a more comprehensible overall measure of the amount of work done.
4. Sources
4.1 Information on road lengths is mainly obtained from annual returns made to the Scottish Executive by Councils and by the trunk road management operators. (The figures for motorways for 2000 were prepared by the Scottish Executive using a GIS - see section 4.4). These returns provide the total lengths of the roads for which the Council or trunk road management operator is responsible. The road lengths are categorised in a number of ways (e.g. by class of road, by type of road and by speed limit).
4.2 Because the returns provide only the total lengths of roads of various types (they do not provide any information about any individual roads) they can contain errors which cannot be detected, and, even in cases where an error is suspected, it may not be possible to determine how the figures should be corrected. There are a few cases of apparently unusual changes in the figures between one year and the next, which may be due to errors in the statistical returns (for example, it appears that the figures for dual carriageways may have been affected by the double-counting of some lengths of dual carriageway in some years).
4.3 Some councils now calculate their road lengths using GISs, which should reduce the number of errors in the longer term. However, changing to a GIS as the source of the statistics can cause a discontinuity in the figures. They will no longer be affected by any errors inherent in the old method of estimation. There may also be changes in the basis of the figures - for example, in the way in which the lengths of road at roundabout are counted. Different methods can give different results: for example, the straight-line distance across a roundabout will differ from the distance around the roundabout; or just half the distance around might be used (to represent the average distance which is travelled on the roundabout).
4.4 The effect of a change to a GIS as the source of the data can be seen using the figures for motorways for 2000, which were prepared by the Scottish Executive using a GIS. These may differ from the figures reported by the trunk road management operators for 1999 (which were published last year), even in areas where there were no changes to the motorway network between April 1999 and April 2000. The Scottish Executive derived its figures using particular ways of counting the road lengths for (eg) slip roads and roundabouts. The precise basis of the figures which were reported for earlier years is not known.
4.5 The physical condition of Motorways and trunk roads is monitored by annual condition surveys which are undertaken for the Scottish Executive by specialist contractors. The surveys are designed to provide information about the structural, surface and safety condition of the road surface (which are referred to as "pavements" by the engineers). The data from the surveys is processed annually in a Pavement Management system so as to identify objectively performance and to target the available funds on those areas of greatest need.
5. Further Information
5.1 Further information on GB road network statistics can be found in the former Department of Environment, Transport and the Regions’ annual publications "Road Lengths in Great Britain" and "Transport Statistics Great Britain".
5.2 For further information on road lengths in Scotland, contact Mr Stuart Hay of the Scottish Executive Road Network Management and Maintenance Division (tel: 0131 244 0458).
5.3 For further information on maintenance and the condition of Scotland’s trunk road network, contact Mr David Arran of the Scottish Executive Road Network Management and Maintenance Division (tel: 0131 244 0460).
< Previous | Contents | Next >
The information contained on this WWW site is Crown Copyright but may be reproduced without formal permission or charge for personal or in-house use. Privacy and Content Disclaimer.
For general enquiries about this web site email ceu@scotland.gov.uk or fill out our online questionnaire.
