Economic, Environmental and Social Impacts of Changes in Maintenance Spend on Local Roads in Scotland
12 Scaling-up to the Full Network
12.1 Overall approach
To understand the effects of reductions in maintenance funding for local roads it was not possible in this study to analyse the whole network. The approach was therefore based on the analysis of the road networks in 8 sample Local Authorities to represent the national network. The results from the analysis of the 8 Authorities were scaled to represent the national network.
Some of the effects of changes in maintenance funding (e.g. vehicle operating costs) are driven by the condition of the road network and the traffic using the network, while others (e.g. costs of delays to traffic due to roadworks) are driven by the amount of maintenance undertaken on the network and the level of traffic. Each aspect of cost was therefore scaled independently and the scaled costs combined to show the overall costs for the network.
For all aspects of costs, the Local Authorities are considered in the groups shown in Appendix C (i.e. rural, urban, semi-urban, city). Each type of Authority is represented in the 8 sample Authorities and the results of the analyses for each Authority type were used to scale up the costs for the Authorities of that type that were not included in the sample Authorities.
Where the 8 sample Authorities included more than one Authority for an Authority type (e.g. there were 3 rural Authorities in the sample). The results from all the sample Authorities of the type were combined for use in estimating the costs for the Authorities of that type, not in the sample. The approach adopted for scaling up the results was the same for all Authority types but the analysis was carried out separately for each Authority type.
Where there was more than one sample Authority of the same type, the results from the analyses of the sample Authorities of that type were combined to create a representative factor that could be used to scale up the costs for the Authorities of that type, not included in the sample Authorities.
12.2 Representative factors
For each aspect of cost (e.g. vehicle operating cost) and the network and vehicle type considered, a representative factor for each Authority type was derived based on the sample Authorities of that type. These factors were used to convert the total costs for the sample Authorities of that type to a 'fingerprint' value for that aspect of cost to be used for all Authorities of that type not in the sample. The equivalent factor for each Authority not in the sample was then calculated and used to derive the value for each aspect of cost for each Authority.
Where the sample Authorities included more than one Authority of the same type, the results from the sample Authorities were used in the total cost for the network, not costs derived using the representative factors for that Authority type.
The relationship for the change in vehicle speed as roads deteriorate was based on a study of the change in traffic speed on trunk roads in England. This cost was therefore estimated only for urban and rural local A roads and the results from the sample Authorities were scaled only for these road types. No costs or benefits were estimated for changes in traffic speed due to road surface condition on other road types.
12.3 Total network cost
The total cost for the network was the sum of each of the costs for all road types and vehicle types in all Authorities. A description of the calculations applied to the sample analyses for each aspect of cost is given in Appendix L. The results from the application of the scaling methodology are shown in Table 12.1 to Table 12.3 in undiscounted 2002 prices for each budget scenario. The sample Authorities are highlighted in light blue.
Authority | Vehicle Operating Costs (£m) | Travel Time Delay Costs (£m) | User Delay Costs (£m) | CO2 Emissions Cost (Network Condition) (£m) | Delay Carbon Costs (£m) | Works Carbon Cost (£m) | Baselined Cumulative Depreciation (£m) |
---|---|---|---|---|---|---|---|
Aberdeenshire | 8374 | 39 | 24 | 455 | 0 | 5 | 68 |
Dumfries and Galloway | 3149 | 21 | 10 | 171 | 0 | 6 | 31 |
Edinburgh, City of | 9610 | 47 | 206 | 513 | 5 | 3 | 17 |
Fife | 8682 | 48 | 60 | 474 | 1 | 5 | 1 |
Glasgow City | 6297 | 49 | 16 | 323 | 0 | 1 | 67 |
Highland | 4719 | 29 | 8 | 258 | 0 | 4 | 94 |
North Lanarkshire | 8016 | 33 | 30 | 423 | 0 | 2 | 17 |
South Ayrshire | 2667 | 15 | 3 | 140 | 0 | 1 | 28 |
Rural | 22775 | 146 | 198 | 1244 | 1 | 17 | 16 |
Rural | 41175 | 302 | 59 | 2297 | 0 | 12 | 93 |
Rural | 41398 | 358 | 92 | 2334 | 0 | 12 | 37 |
Rural | 23823 | 128 | 23 | 1281 | 0 | 2 | 38 |
Rural | 22489 | 149 | 110 | 1236 | 1 | 12 | 16 |
Urban | 5570 | 17 | 27 | 289 | 0 | 1 | 3 |
Urban | 11285 | 50 | 68 | 593 | 0 | 2 | 9 |
Urban | 13200 | 44 | 106 | 687 | 0 | 1 | 9 |
Urban | 7846 | 23 | 18 | 405 | 0 | 0 | 12 |
Urban | 13929 | 68 | 75 | 737 | 0 | 1 | 6 |
Urban | 8583 | 27 | 45 | 447 | 0 | 1 | 13 |
Urban | 7608 | 20 | 75 | 395 | 0 | 2 | 4 |
Urban | 10392 | 67 | 37 | 572 | 0 | 1 | 12 |
Semi Urban | 4880 | 22 | 74 | 261 | 0 | 2 | 4 |
Semi Urban | 6344 | 36 | 54 | 344 | 0 | 2 | 3 |
Semi Urban | 13838 | 110 | 47 | 775 | 0 | 1 | 13 |
Semi Urban | 6754 | 45 | 185 | 368 | 1 | 5 | 15 |
Semi Urban | 8570 | 46 | 50 | 461 | 0 | 2 | 10 |
Semi Urban | 8708 | 27 | 100 | 463 | 0 | 4 | 4 |
Semi Urban | 12048 | 73 | 17 | 621 | 0 | 0 | 25 |
City | 7624 | 42 | 110 | 392 | 1 | 1 | 9 |
City | 24847 | 196 | 67 | 1396 | 0 | 10 | 33 |
Islands | 6609 | 36 | 37 | 359 | 0 | 4 | 7 |
Islands | 10215 | 41 | 42 | 544 | 0 | 4 | 12 |
Islands | 392020 | 2352 | 2073 | 21258 | 16 | 124 | 727 |
Total | 8374 | 39 | 24 | 455 | 0 | 5 | 68 |
Note: (2002 prices undiscounted)
Authority | Vehicle Operating Costs (£m) | Travel Time Delay Costs (£m) | User Delay Costs (£m) | CO2 Emissions Cost (Network Condition) (£m) | Delay Carbon Costs (£m) | Works Carbon Cost (£m) | Baselined Cumulative Depreciation (£m) |
---|---|---|---|---|---|---|---|
Aberdeenshire | 8413 | 40 | 19 | 455 | 0 | 1 | 76 |
Dumfries and Galloway | 3173 | 22 | 8 | 171 | 0 | 2 | 45 |
Edinburgh, City of | 9675 | 51 | 176 | 514 | 2 | 1 | 22 |
Fife | 8760 | 52 | 47 | 475 | 0 | 1 | 9 |
Glasgow City | 6327 | 50 | 13 | 323 | 0 | 0 | 71 |
Highland | 4739 | 30 | 6 | 258 | 0 | 1 | 103 |
North Lanarkshire | 8067 | 35 | 24 | 424 | 0 | 0 | 19 |
South Ayrshire | 2676 | 15 | 3 | 140 | 0 | 0 | 30 |
Rural | 22892 | 152 | 154 | 1245 | 1 | 13 | 18 |
Rural | 41368 | 314 | 46 | 2300 | 0 | 9 | 109 |
Rural | 41585 | 372 | 72 | 2337 | 0 | 9 | 42 |
Rural | 23949 | 133 | 18 | 1282 | 0 | 2 | 45 |
Rural | 22600 | 155 | 86 | 1237 | 0 | 9 | 18 |
Urban | 5604 | 18 | 22 | 290 | 0 | 1 | 4 |
Urban | 11354 | 53 | 55 | 594 | 0 | 1 | 10 |
Urban | 13289 | 46 | 87 | 689 | 0 | 1 | 11 |
Urban | 7891 | 24 | 14 | 405 | 0 | 0 | 13 |
Urban | 14019 | 72 | 62 | 739 | 0 | 1 | 7 |
Urban | 8639 | 28 | 35 | 448 | 0 | 1 | 15 |
Urban | 7658 | 21 | 61 | 395 | 0 | 2 | 5 |
Semi Urban | 10468 | 72 | 29 | 573 | 0 | 1 | 15 |
Semi Urban | 4921 | 24 | 60 | 261 | 0 | 2 | 6 |
Semi Urban | 6394 | 38 | 42 | 345 | 0 | 1 | 4 |
Semi Urban | 13934 | 117 | 37 | 776 | 0 | 1 | 17 |
Semi Urban | 6804 | 48 | 142 | 369 | 1 | 4 | 20 |
Semi Urban | 8637 | 49 | 39 | 462 | 0 | 2 | 13 |
Semi Urban | 8776 | 29 | 74 | 464 | 0 | 3 | 5 |
City | 12130 | 78 | 14 | 622 | 0 | 0 | 27 |
City | 7677 | 45 | 91 | 392 | 1 | 1 | 10 |
Islands | 24958 | 204 | 53 | 1397 | 0 | 8 | 37 |
Islands | 6642 | 38 | 29 | 359 | 0 | 3 | 8 |
Islands | 10270 | 42 | 34 | 545 | 0 | 4 | 14 |
Total | 394292 | 2469 | 1650 | 21289 | 9 | 86 | 845 |
Note: (2002 prices undiscounted)
Authority | Vehicle Operating Costs (£m) | Travel Time Delay Costs (£m) | User Delay Costs (£m) | CO2 Emissions Cost (Network Condition) (£m) | Delay Carbon Costs (£m) | Works Carbon Cost (£m) | Baselined Cumulative Depreciation (£m) |
---|---|---|---|---|---|---|---|
Aberdeenshire | 8454 | 42 | 13 | 456 | 0 | 1 | 87 |
Dumfries and Galloway | 3195 | 23 | 6 | 171 | 0 | 1 | 54 |
Edinburgh, City of | 9739 | 56 | 141 | 514 | 1 | 1 | 26 |
Fife | 8835 | 56 | 32 | 476 | 0 | 1 | 18 |
Glasgow City | 6349 | 52 | 9 | 324 | 0 | 0 | 73 |
Highland | 4761 | 31 | 4 | 259 | 0 | 1 | 113 |
North Lanarkshire | 8121 | 37 | 18 | 424 | 0 | 0 | 21 |
South Ayrshire | 2686 | 16 | 2 | 140 | 0 | 0 | 32 |
Rural | 23013 | 159 | 112 | 1247 | 1 | 10 | 21 |
Rural | 41573 | 327 | 33 | 2303 | 0 | 7 | 121 |
Rural | 41786 | 388 | 52 | 2340 | 0 | 7 | 46 |
Rural | 24078 | 139 | 13 | 1284 | 0 | 1 | 50 |
Rural | 22716 | 161 | 62 | 1239 | 0 | 7 | 21 |
Urban | 5640 | 19 | 16 | 290 | 0 | 1 | 4 |
Urban | 11427 | 55 | 42 | 595 | 0 | 1 | 12 |
Urban | 13382 | 49 | 65 | 690 | 0 | 1 | 12 |
Urban | 7937 | 25 | 11 | 406 | 0 | 0 | 15 |
Urban | 14114 | 76 | 48 | 740 | 0 | 1 | 8 |
Urban | 8699 | 30 | 27 | 449 | 0 | 0 | 17 |
Urban | 7710 | 22 | 46 | 396 | 0 | 1 | 5 |
Semi Urban | 10541 | 77 | 21 | 575 | 0 | 1 | 18 |
Semi Urban | 4963 | 25 | 43 | 262 | 0 | 1 | 7 |
Semi Urban | 6441 | 41 | 29 | 345 | 0 | 1 | 5 |
Semi Urban | 14022 | 125 | 26 | 777 | 0 | 1 | 21 |
Semi Urban | 6852 | 51 | 99 | 370 | 1 | 3 | 25 |
Semi Urban | 8702 | 52 | 27 | 463 | 0 | 1 | 16 |
Semi Urban | 8834 | 31 | 48 | 465 | 0 | 2 | 7 |
City | 12203 | 84 | 11 | 623 | 0 | 0 | 29 |
City | 7722 | 48 | 69 | 393 | 1 | 1 | 10 |
Islands | 25077 | 212 | 38 | 1399 | 0 | 6 | 41 |
Islands | 6677 | 39 | 22 | 360 | 0 | 2 | 9 |
Islands | 10326 | 44 | 25 | 546 | 0 | 3 | 16 |
Total | 396577 | 2592 | 1212 | 21321 | 7 | 62 | 961 |
Note: (2002 prices undiscounted)