Chapter 4: Road Network

Scottish Transport  Statistics, No 36, 2017 Edition

Chapter 4: Road Network

Chapter 4: Road Network

1. Introduction

1.1 This chapter provides information about public road lengths by local authority, road class, type and speed limit. It also includes statistics on the amount of trunk road constructed/re-surfaced and information on the residual life of the trunk road network.

1.2. Unusual year to year changes in the reported road lengths may be due to the gradual introduction of Geographical Information Systems (GIS) to calculate road lengths by the data providers- see Notes and Definitions section, page 247.

Key Points

  • Scotland has 56,250 km of road network
  • Seven per cent is trunk road (1% is motorway)
  • Scotland has 10.4 km of road per 1,000 people compared to 6.2 km in GB.

2. Main Points

Road length

2.1 There were 56,250 kilometres of public road in Scotland at 31 March 2017. The trunk road network accounted for 7% of the total. Other (non-trunk) A roads represented 13% of the total. Minor roads (B and C roads, and unclassified roads) accounted for the remaining 80% of roads. (Table 4.1)

2.2 The length of the motorway network increased by 1% between April 2016 and April 2017. (Table 4.1)

2.3 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. These three Local Authorities account for almost a third of Scotland's road network. (Table 4.2)

Road Maintenance

2.4 Overall there was an increase of 9% in the amount of trunk road that was newly constructed, reconstructed, strengthened or surface dressed in 2016-17 compared to the previous year. (Table 4.3)

2.5 In 2016-17, 16.9% of the motorway network, 10.7% of the dual carriageway and 11.5% of the single carriageway trunk road network required close monitoring of the state of the road surface. (Table 4.5 (b))

2.6 In 2016-17 the National Road Condition Indicator (RCI) showed 29% of the local authority A road network may, following more detailed examination, require some kind of maintenance (see the Notes and Definitions section, page 247). For the whole of the local authority network (all road categories), about 36% may similarly require some kind of maintenance. (Table 4.6)

Table 4.1 Public road lengths by class, type and speed limit 1,2
  2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016
Trunk roads 3, 6
Motorways Kilometres
Excluding slip roads 392 392 392 390 389 396 420 420 420 420 440
Including slip roads 546 547 547 546 544 558 599 599 600 601 632
A roads
Dual carriageway 531 521 521 523 523 511 500 500 504 504 505
Single carriageway 2,330 2,323 2,323 2,332 2,327 2,282 2,279 2,274 2,326 2,326 2,327
Other inc slips/roundabout 111 114 114 119 123 185 188 191 208 208 204
Total 2,972 2,958 2,958 2,974 2,974 2,978 2,968 2,966 3,037 3,037 3,036
by speed limit:
up to 40 mph 232 229 229 226 233 235 237 237 243 243 245
over 40 mph 2,740 2,730 2,730 2,748 2,740 3,302 3,330 3,328 3,395 3,395 3,424
All trunk roads 3,4 3,518 3,505 3,505 3,520 3,518 3,536 3,566 3,565 3,637 3,638 3,669
Local Authority major roads 7
Motorways
Excluding slip roads  -  -  -  -  -  -  -  -  -  -
Including slip roads  -  -  -  -  -  -  -  -  -  -
A roads
Dual carriageway 5 242 242 243 243 229 232 268 270 272 272 272
Single carriageway 5 7,182 7,139 7,178 7,178 7,185 7,235 7,204 7,203 7,134 7,142 7,146
Total 7,424 7,381 7,421 7,421 7,414 7,467 7,473 7,473 7,406 7,414 7,418
by speed limit:
up to 40 mph 1,485 1,491 1,515 1,508 1,509 1,559 1,567 1,572 1,616 1,621 1,630
over 40 mph 5,939 5,889 5,906 5,913 5,905 5,907 5,906 5,901 5,791 5,792 5,788
All LA major roads4 7,424 7,381 7,421 7,421 7,414 7,467 7,473 7,473 7,406 7,414 7,418
Local Authority minor roads 7
B roads
limit up to 40 mph 1,141 1,152 1,174 1,176 1,170 1,189 1,194 1,194 1,228 1,226 1,230
limit over 40 mph 6,318 6,349 6,292 6,318 6,311 6,310 6,309 6,305 6,270 6,276 6,268
Total  7,459 7,501 7,466 7,493 7,481 7,499 7,504 7,500 7,498 7,502 7,498
C roads
limit up to 40 mph 1,353 1,266 1,576 1,556 1,555 1,582 1,586 1,593 1,621 1,653 1,658
limit over 40 mph 9,065 9,104 9,091 9,102 9,098 9,105 9,104 9,098 9,060 9,051 9,045
Total  10,419 10,371 10,667 10,658 10,653 10,687 10,690 10,691 10,681 10,703 10,703
Unclassified roads
limit up to 40 mph 14,465 14,768 14,573 14,714 14,828 14,856 14,948 15,020 15,097 15,198 15,273
limit over 40 mph 11,683 11,661 11,712 11,726 11,732 11,727 11,732 11,728 11,735 11,696 11,688
Total  26,148 26,429 26,285 26,440 26,560 26,583 26,680 26,748 26,832 26,895 26,962
All LA minor roads 44,026 44,300 44,418 44,591 44,694 44,769 44,873 44,938 45,011 45,100 45,163
All roads (trunk and LA) 3
Motorways
Excluding slip roads 392 392 392 390 389 396 420 420 420 420 440
Including slip roads 546 547 547 546 544 558 599 599 600 601 632
A, B and C roads
Dual carriageway 5 773 763 764 766 752 742 768 770 776 775 776
Single carriageway 5 27,390 27,333 27,634 27,661 27,646 27,703 27,677 27,667 27,639 27,674 27,675
Total 28,274 28,210 28,512 28,546 28,522 28,630 28,633 28,629 28,623 28,656 28,656
by speed limit:
up to 40 mph 4,212 4,138 4,494 4,465 4,467 4,565 4,584 4,595 4,708 4,743 4,763
over 40 mph 24,062 24,073 24,019 24,081 24,054 24,624 24,648 24,632 24,515 24,515 24,525
Unclassified roads
limit up to 40 mph 14,465 14,768 14,573 14,714 14,828 14,856 14,948 15,020 15,097 15,198 15,273
limit over 40 mph 11,683 11,661 11,712 11,726 11,732 11,727 11,732 11,728 11,735 11,696 11,688
Total 26,148 26,429 26,285 26,440 26,560 26,583 26,680 26,748 26,832 26,895 26,962
All roads 3,4 54,968 55,186 55,344 55,532 55,626 55,772 55,912 55,975 56,054 56,152 56,250

Source: Transport Scotland - Not National Statistics
1. Motorway road lengths are derived from GIS from 2000 onwards - see commentary for more details.
2. Road lengths are physical length rather than carriageway length e.g. 10km of dual carriageway counts as 10km, not 20km.
3. These figures now include A road slip roads which have been excluded from the figures in previous publications. The time series has been updated to include this data resulting
in an increase of 3-4% in Trunk road length and an increase in overall road length of 0.2%. The methodology for calculating the trunk road totals from the database has also
changed resulting in some small changes to road lengths from those previously published.
4.Trunk road lengths for these roads have now been derived more accurately using a GIS system from 2006.
5. For 2008 and 2009 single and dual carriageways figures are estimated.
6. As at 30 May 2014.
7. Local authority road lengths at the end of the financial year e.g. 2013=2013/14.

Table 4.2     Public road lengths by council area and class, 2016/17
Council Trunk 3 Local Authority 2,5 Total
Motorway 1 Motorway
slips		 A Roads Total A
Roads		 B
Roads		  C
Roads		 Unclass-
ified		 Total
kilometres
Aberdeen City  -  -  31  31  58  42  93  720  913  944
Aberdeenshire  -  -  192  192  687  799  1,540  2,494  5,520  5,712
Angus  -  -  53  53  193  255  489  876  1,812  1,865
Argyll & Bute  -  -  296  296  505  614  434  732  2,285  2,581
Clackmannanshire   -  -  3  3  49  34  28  177  288  291
Dumfries & Galloway  59  14  279  352  494  735  1,178  1,759  4,166  4,518
Dundee City  -  -  19  19  36  17  96  414  563  582
East Ayrshire  11  4  56  70  124  193  211  626  1,154  1,224
East Dunbartonshire  -  -  57  47  34  377  515  515
East Lothian  -  -  59  59  95  169  223  444  931  991
East Renfrewshire  9  3  10  22  31  50  83  311  474  497
Edinburgh, City of  15  12  34  60  135  51  119  1,111  1,417  1,477
Eilean Siar  -  -  340  177  189  486  1,191  1,191
Falkirk  39  13  5  58  114  96  118  646  974  1,032
Fife  16  6  96  118  322  326  352  1,418  2,417  2,535
Glasgow, City of  53  50  1  105  135  64  209  1,404  1,812  1,916
Highland  -  -  959  959  1,392  976  1,440  2,937  6,745  7,704
Inverclyde  -  -  28  28  24  23  54  269  369  397
Midlothian  -  -  39  39  93  100  101  389  683  721
Moray  -  -  98  98  157  296  366  736  1,555  1,654
North Ayrshire  -  -  68  68  101  155  207  573  1,036  1,104
North Lanarkshire 4  59  28  19  107  147  143  247  1,030  1,567  1,674
Orkney Islands  -  -  161  205  160  459  985  985
Perth & Kinross  39  13  209  261  435  367  638  1,050  2,490  2,751
Renfrewshire  18  10  26  55  65  62  140  554  821  876
Scottish Borders  -  -  167  167  459  599  769  1,148  2,974  3,141
Shetland Islands  -  -  225  162  199  464  1,049  1,049
South Ayrshire  -  -  93  93  108  209  232  623  1,172  1,264
South Lanarkshire  67  20  56  143  268  247  444  1,312  2,271  2,414
Stirling  21  6  116  143  212  161  170  473  1,017  1,160
West Dunbartonshire  -  -  23  23  46  8  27  295  376  399
West Lothian  33  13  -  46  152  117  116  654  1,040  1,086
Total  440  193  3,036  3,669  7,418  7,498  10,703  26,962  52,581  56,250
percentages
Aberdeen City - - 1.0 0.8 0.8 0.6 0.9 2.7 1.7 1.7
Aberdeenshire - - 6.3 5.2 9.3 10.7 14.4 9.3 10.5 10.2
Angus - - 1.7 1.4 2.6 3.4 4.6 3.2 3.4 3.3
Argyll & Bute - - 9.8 8.1 6.8 8.2 4.1 2.7 4.3 4.6
Clackmannanshire  - - - 0.1 0.7 0.5 0.3 0.7 0.5 0.5
Dumfries & Galloway 13.4 7.4 9.2 9.6 6.7 9.8 11.0 6.5 7.9 8.0
Dundee City - - 0.6 0.5 0.5 0.2 0.9 1.5 1.1 1.0
East Ayrshire 2.4 1.9 1.8 1.9 1.7 2.6 2.0 2.3 2.2 2.2
East Dunbartonshire - - - 0.0 0.8 0.6 0.3 1.4 1.0 0.9
East Lothian - - 2.0 1.6 1.3 2.3 2.1 1.6 1.8 1.8
East Renfrewshire 2.1 1.4 0.3 0.6 0.4 0.7 0.8 1.2 0.9 0.9
Edinburgh, City of 3.3 6.0 1.1 1.6 1.8 0.7 1.1 4.1 2.7 2.6
Eilean Siar - - - 0.0 4.6 2.4 1.8 1.8 2.3 2.1
Falkirk 8.9 7.0 0.2 1.6 1.5 1.3 1.1 2.4 1.9 1.8
Fife 3.6 3.0 3.2 3.2 4.3 4.3 3.3 5.3 4.6 4.5
Glasgow, City of 12.2 25.9 0.0 2.8 1.8 0.8 2.0 5.2 3.4 3.4
Highland - - 31.6 26.1 18.8 13.0 13.5 10.9 12.8 13.7
Inverclyde - - 0.9 0.8 0.3 0.3 0.5 1.0 0.7 0.7
Midlothian - - 1.3 1.1 1.2 1.3 0.9 1.4 1.3 1.3
Moray - - 3.2 2.7 2.1 4.0 3.4 2.7 3.0 2.9
North Ayrshire - - 2.3 1.9 1.4 2.1 1.9 2.1 2.0 2.0
North Lanarkshire 13.5 14.8 0.6 2.9 2.0 1.9 2.3 3.8 3.0 3.0
Orkney Islands - - - 0.0 2.2 2.7 1.5 1.7 1.9 1.8
Perth & Kinross 8.8 7.0 6.9 7.1 5.9 4.9 6.0 3.9 4.7 4.9
Renfrewshire 4.2 5.4 0.9 1.5 0.9 0.8 1.3 2.1 1.6 1.6
Scottish Borders - - 5.5 4.5 6.2 8.0 7.2 4.3 5.7 5.6
Shetland Islands - - - 0.0 3.0 2.2 1.9 1.7 2.0 1.9
South Ayrshire - - 3.1 2.5 1.5 2.8 2.2 2.3 2.2 2.2
South Lanarkshire 15.2 10.3 1.9 3.9 3.6 3.3 4.1 4.9 4.3 4.3
Stirling 4.9 3.3 3.8 3.9 2.9 2.1 1.6 1.8 1.9 2.1
West Dunbartonshire - - 0.7 0.6 0.6 0.1 0.3 1.1 0.7 0.7
West Lothian 7.6 6.6 - 1.3 2.0 1.6 1.1 2.4 2.0 1.9
Total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0

Source: Transport Scotland - Not National Statistics
1. Motorway road lengths have been consolidated using a GIS system which means that there will be some changes to previously published figures.
2. Triangulation with other sources of road length data has occurred to improve the quality of the information. Figures may not be comparable with previous editions.
3. As at 30 May 2016.
4. The drop in the length of trunk A roads from last year is probably due to the detrunking of A80 with the opening of the M80.
5. Local authority road lengths at the end of the financial year.

Table 4.3     Trunk road constructed/re-surfaced etc
  2006-07  2007-08  2008-09  2009-10 2010-11  2011-12  2012-13 2013-14  2014-15  2015-16  2016-17 (prov)
Equivalent road lane length lane-kilometres (estimated)
New roads
   constructed/opened  7  -  58  -  52  132  -  18  3  3  0.5
Reconstructed  114  80  56  51  27  57  1  9  7  -  1
Strengthened  324  170  194  213  239  168  338  360  365  367  381
Surface dressed  88  79  123  30  35  10  21  11  14  8  29
Total 533  329  431  294  353  367  360  398  389  378  412
Percentages of total  percentages 
New roads
   constructed/opened 1  -  13  -  15  36  -  5  1  1  0
Reconstructed 1 21  24  13  17  8  16  0  2  2  -  0
Strengthened 61  52  45  72  68  46  94  90  94  97  93
Surface dressed 17  24  29  10  10  3  6  3  4  2  7
Total 100  100  100  100  100  100  100  100  100  100  100

Source: Transport Scotland - Not National Statistics

Table 4.4 (a) Trunk road constructed/re-surfaced etc, by unit, 2015-16
Unit New road
constructed
for traffic		 Reconstructed Strengthened Surface
Dressed		 Total
Equivalent road lane length lane-kilometres (estimated)
NW  - 0 141 1 142
NE  3  - 74 2 79
SW  - 0 65 4 69
SE  -  - 81 1 82
FBOC  -  - 6  - 6
Total  3  -  367  8  378
Percentages of total percentages
NW - - 38 13 38
NE 100 - 20 25 21
SW - - 18 50 18
SE - - 22 13 22
FBOC - - 2 - 2
Total 100 - 100 100 100

Source: Transport Scotland - Not National Statistics

Table 4.4 (b)     Trunk road constructed/re-surfaced etc, by unit, 2016-17 (provisional)  
Unit New road
constructed
for traffic		 Reconstructed Strengthened Surface
Dressed		 Total
Equivalent road lane length lane-kilometres (estimated)
NW  -  - 124 11 135
NE  0.5  1 54 3 58.647
SW 1  -  - 64 5 69
SE 1  -  - 136 10 146
FBOC  -  - 3  - 3
Total  0.5  1 381 29 411.647
Percentages of total percentages
NW - - 33 38 33
NE 100 100 14 10 14
SW - - 17 17 17
SE - - 36 34 35
FBOC - - 1 - 1
Total 100 100 100 100 100

Source: Transport Scotland - Not National Statistics

Table 4.5     Trunk road network: Residual Life1 (years) (a)   Residual Life of Pavements (i.e. road surface) as percentage of whole network
Residual Life (years)
<0 0-4 5-9 10-14 15-19 >19
percentages
1997-98 11 8 11 8 8 54
1998-99 10 9 9 8 7 57
1999-00 10 8 10 9 10 53
2000-01 9 7 9 8 8 59
2001-02 4 4 7 7 10 68
2002-03 4 4 7 7 11 67
2003-04 4 4 6 7 12 67
2004-05 4 5 6 7 13 65
2005-06 4 4 6 7 15 63
2006-07 5 4 6 7 15 63
2007-08 4 4 7 7 13 65
2008-09 4 4 6 7 11 68
2009-10 5 5 7 8 11 64
2010-11 5 4 6 7 9 69
2011-122  10 7 10 10 11 52
2012-13 13 8 10 10 12 46
2013-14 14 8 10 9 11 49
2014-15 13 7 9 9 12 50
2015-16 12 9 9 9 13 48
2016-174 12 9 9 9 12 49
Operating Company Areas 2016-17 4
Forth Bridges Unit 17 10 9 10 17 37
North West Unit 10 7 8 8 13 53
North East Unit 13 10 10 10 12 45
South East Unit 9 10 11 9 11 50
South West Unit 17 8 8 8 12 47
Table 4.5 Trunk road network: Residual Life1 (years) (b) The proportion of the motorway/dual and single carriageway trunk road network, which require close monitoring 3 
Motorways Dual carriageways Single carriageways
Requires close
monitoring		 Requires close
monitoring		 Requires close
monitoring
% % %
2002-03 7.5 5.2
2003-04 9.0 5.1
2004-05 9.2 3.9
2005-06 6.7 3.2
2006-07 6.1 2.7
2007-08 8.2 3.9
2008-09 4.3 4.1
2009-10 6.3 5.5 3.7
2010-11 6.2 3.4 4.2
2011-122 12.9 9.1 10.3
2012-13 23.1 13.3 11.6
2013-14 23.4 15.0 10.3
2014-15 22.9 10.4 11.3
2015-16 21.5 9.8 10.5
2016-174 16.9 10.7 11.5
Operating Company Areas 2016-17 4
Forth Bridges Unit 20.3 8.01  - 
North West Unit  -  10.13 10.15
North East Unit 16.23 7.99 19.55
South East Unit 11.44 6.65 7.33
South West Unit 22.73 19.89 12.4

Source: Transport Scotland - Not National Statistics
1. Residual life represents the number of years to elapse before the pavement reaches the stage when it may be necessary to undertake relatively more expensive reconstruction rather than strengthening to restore its full life.
2 Method of calculation changed in 2011-12.
3. The part of the network that requires close monitoring is that which has a residual life of less than zero. Note: it has been decided that surveyed network length is not required as the figures produced are now representative of the whole network as shown in Table 4.1
4. These figures are provisional.

Table 4.6    Local authority road network condition  1,2
A roads B roads C roads Unclassified All roads
Condition Condition Condition Condition Condition
Red Amber Red Amber Red Amber Red Amber Red Amber
(a) in each Council area:  2016-17 percentage 
Aberdeen City 3 18 3 21 4 23 4 25 4 24
Aberdeenshire 3 22 2 20 2 17 6 24 4 21
Angus 2 20 3 30 4 24 8 27 6 26
Argyll & Bute 9 36 21 43 18 42 16 37 16 39
Clackmannanshire  2 20 3 24 3 25 8 33 6 29
Dumfries & Galloway 5 29 5 30 9 34 18 38 12 35
Dundee City 2 16 1 18 1 14 5 27 4 23
East Ayrshire 2 17 6 28 8 31 12 34 9 30
East Dunbartonshire 5 25 4 25 4 22 9 32 8 30
East Lothian 3 27 5 31 3 27 4 27 4 28
East Renfrewshire 2 14 3 27 8 25 10 34 9 31
Edinburgh, City of 4 21 3 17 4 21 7 30 6 28
Eilean Siar 7 30 7 32 7 43 7 38 7 36
Falkirk 3 26 6 34 5 33 5 30 5 30
Fife 4 24 5 28 3 26 5 30 4 28
Glasgow, City of  3 22 1 18 1 15 6 29 5 26
Highland 4 25 7 30 9 31 12 31 9 30
Inverclyde 3 26 7 31 9 35 9 32 9 32
Midlothian 3 18 4 25 3 26 5 30 4 27
Moray 3 23 2 21 3 19 5 26 3 23
North Ayrshire 9 27 5 31 12 39 6 29 7 31
North Lanarkshire 2 18 2 20 3 22 6 31 5 27
Orkney Islands 2 20 2 16 2 13 4 21 3 18
Perth & Kinross 7 33 6 34 6 32 7 28 7 30
Renfrewshire 2 20 3 24 8 29 8 29 7 28
Scottish Borders 5 29 7 36 8 35 14 41 10 37
Shetland Islands 2 18 6 27 3 28 13 37 8 30
South Ayrshire 6 32 8 36 8 32 10 33 9 33
South Lanarkshire 2 20 2 22 5 32 6 29 5 28
Stirling 4 27 8 34 9 33 16 35 11 33
West Dunbartonshire 3 24 2 19 5 25 6 30 5 28
West Lothian 2 17 3 24 7 35 4 26 4 26
Scotland 4 25 6 29 6 28 9 31 7 29
(b) for Scotland as a whole:  2005-06  to 2016-17 (New RCI  Series) 2
2005-06 4 27 4 28 4 31 .. .. .. ..
2006-07 4 29 4 29 4 32 .. .. .. ..
2007-08 5 29 6 34 5 33 .. .. .. ..
2008-09 5 28 5 34 5 33 7 37 6 34
2009-10 6 30 6 35 5 33 8 39 7 36
2010-11 6 30 7 36 7 35 10 42 8 38
2011-12 6 30 8 36 8 36 8 38 8 36
2012-13 5 24 7 28 7 28 9 30 7 29
2013-14 5 24 7 28 8 28 9 30 8 29
2014-15 5 24 7 29 9 29 9 30 8 29
2015-16 4 25 6 29 6 28 9 31 7 29
2016-17 4 25 6 29 6 28 9 31 7 29
(b) for Scotland as a whole:  2002-03 3 to 2007-08 (Old SPI  Series)
2002-03 4 9 37 .. .. .. .. .. .. .. ..
2003-04 7 33 12 45 8 37 18 52 13 45
2004-05 5 6 31 10 43 5 31 15 50 11 42
2005-06 6 31 9 40 4 29 14 51 10 42
2006-07 6 34 11 35 5 29 18 57 13 47
2007-08 6 34 10 46 6 36 16 53 12 46

Source: Scottish Road Maintenance Condition Survey - Not National Statistics
1. From 2007-08 the basis of the statutory road performance indicator in Scotland changed to the UK Standard RCI.
2. While it has been possible, following the change to the indicator, to calculate the equivalent RCI value for all classified roads from 2005-06,
it has not been possible to do this in a reliable manner for unclassified roads, owing to a lack of cracking data for those years.
As unclassified roads represent a significant part of the total road network, RCI data for the network is similarly not available for this period
It is important to note that owing to the different formulation, no valid comparison can or should be made between the two series 3. The categories used to indicate the condition of the road are in brief:
amber - further investigation should be undertaken to establish if treatment is required
red - the road has deteriorated to the point at which it is likely repairs to prolong its future life should be undertaken. 4. Information for 2002-03 is available only for A roads.
5. The SPI figures for Scotland in 2004-05 exclude Glasgow, as the survey in Glasgow was undertaken on a
different basis in that year.