Economic, Environmental and Social Impacts of Changes in Maintenance Spend on Local Roads in Scotland

Appendix K Asset Valuation

K.1 Methodology

Depreciation of the road network for each road type, for each of the sample Authorities has been calculated based on the projected carriageway conditions in each of the modelled years (2010, 2013, 2017, 2020, 2025 and 2030) and for each budget scenario. This data was provided by WDM in 2011 prices so these figures were deflated to 2002 prices.

The accumulated depreciation costs for each of the modelled years under the 20% and 40% budget cut scenarios were then linearly interpolated and extrapolated to represent a 35% and 69% budget cut to account for the fact that the WDM model runs were carried out using a 20% and 40% budget cut, but the subjective budget analysis identified that these would be equivalent to a 35% and 69% budget cut in carriageway maintenance respectively.

The accumulated depreciation values were not discounted to a 2010 base. The consideration of the accumulated depreciation in the analysis results has been included as a separate analysis to the main economic analyses. Therefore discounting of the depreciation values was not required for this study.

K.2 Results

The accumulated depreciation results for the 8 sample Authorities are shown in Figure K.1 to Figure K.8.

Figure K.1 Aberdeenshire accumulated depreciation

Figure K.2 Dumfries and Galloway accumulated depreciation

Figure K.3 City of Edinburgh accumulated depreciation

Figure K.4 Fife accumulated depreciation

Figure K.5 Glasgow City accumulated depreciation

Figure K.6 Highland accumulated depreciation

Figure K.7 North Lanarkshire accumulated depreciation

Figure K.8 South Ayrshire accumulated depreciation