Date lodged: 21 December 2017
To ask the Scottish Government, further to the answer to question S5W-13220 by Humza Yousaf on 18 December 2017, whether it will provide details of the calculations and analysis that it used for the expenditure models.
Answered by: Humza Yousaf 10 January 2018
Transport Scotland’s asset investment planning models use information from inspections and surveys undertaken to identify the number of trunk road assets, and assess their current condition. In line with recognised good practice, the condition of the network for future years is predicted based on a series of deterioration curves, and the quantity of network requiring treatment in any given year can be determined. Predictions of expenditure are made for each year under various categories, such as Operating Company Area, road class, and for broad treatment types.
A technical report explaining how the asset investment planning model is used to calculate a backlog figure for trunk road carriageways is available from the Scottish Parliament Information Centre (Bib No. 59463). Further information on asset investment planning is provided in Chapter 5 of the Road Asset Management Plan (RAMP), published January 2016. This can be accessed at https://www.transport.gov.scot/media/32978/j408891.pdf