Economic, Environmental and Social Impacts of Changes in Maintenance Spend on the Scottish Trunk Road Network

14 Conclusions and recommendations

This study has shown there are no established earlier studies that have attempted to assess the overall economic, environmental and social impacts of maintenance budget reductions. Many studies have looked at the effects on future asset condition but not the related external effects.

The overall conclusion from the results of this study is that if Transport Scotland can allow a reduction in its current standards and adopt the lower levels of pavement maintenance funding, then there will be an economic disbenefit to the travelling public, primarily from increased vehicle operating costs.

For the modelling approach and the funding scenarios considered in this study, users experience reduced network performance, with increased costs to Scotland, primarily through vehicle fuel costs.

The effects seen in this analysis depended significantly on the assumptions in the Pavement Network Model on the application of maintenance treatments and continuing the treatment allocation used in year 1 for all future years.

In addition to an economic disbenefit to road users, there is likely to be increased public dissatisfaction with the condition of road network. Customer complaints due to worse surface conditions are likely to increase given recent experience from recent customer satisfaction surveys.

A number of potential impacts have not been assessed in terms of network resilience and risk. Particularly for non pavement aspects, the risks of closures due to unforeseen events will increase as the level of expenditure is reduced and inspection and monitoring budgets are reduced. The risk of large diversions due to higher risk sections of the network becoming more frequently inoperable due to inclement weather could become unacceptable. No estimate has been made of such impacts.

The particular conclusions from this study with costs expressed in 2002 prices are:

From a subjective assessment of the likely distribution of the overall budget reductions across the Transport Scotland maintenance activities it was clear that in the period (2010-2030) considered in this study it is likely that pavement maintenance will suffer a bigger share of the budget reduction than other maintenance areas. The study suggests the pavement maintenance budget would be reduced by 44% and 76% for reductions in the overall maintenance budgets of 20 percent and 40 percent respectively.
The results from the Transport Scotland Pavement Network Model show the condition of Motorways will continue to improve during the first 10 years of the analysis period when budgets are reduced and before the budgets have started to increase, for all the budget levels considered but overall there is a worsening in network pavement condition with the percentage of the network with zero remaining life (i.e. in need of maintenance) predicted to be 25 percent of the network by 2020, compared with 11 percent in 2010 for Scenario 3. The effect of restoring and increasing the budgets between 2020 and 2030 was to forecast the network continues to deteriorate and there to be 29 percent of the network with zero remaining life in 2030.
A brief analysis using HDM-4 has shown that by 2020 there will be an increase in undiscounted vehicle operating costs of more than £600m per year compared with the current level, assuming the current level of maintenance spend is retained. The results also showed there will be further increases if the cuts in the maintenance budget are applied. For the 40 percent budget reduction Scenario, the undiscounted vehicle operating costs were predicted to rise by £673m per year by 2020 compared with the costs in 2010 and by £1.24 billion by 2030.
Using the results from a study carried out some years ago into the effects of pavement condition on traffic speed, the annual undiscounted costs of increased travel time, by 2020, resulting from the worsening in pavement condition, were estimated to be £8m and £12m for the 20 percent and 40 percent budget reduction scenarios respectively.
A QUADRO analysis of a sample of typical maintenance works to assess the impacts on road users from changes in the number of maintenance schemes with the reduced maintenance funding showed in 2030 a reduction in the undiscounted costs of traffic delays to road users at roadworks of 44 percent for the Scenario with a 20 percent cut in overall maintenance budget and a 56 percent reduction for the Scenario with a 40 percent cut in the overall budget. There was still a 20 percent reduction in the annual cost, compared with 2010/11, at the end of the analysis period, after restoration and increase of the maintenance budget.
Although safety would continue to have a high priority if maintenance budgets are cut, the poorer pavement condition resulting from the reduced maintenance funding was predicted to lead to lower levels of skid resistance. The increase in accidents that may accompany the lower levels of skid resistance for the Scenario with a 40 percent cut in the overall maintenance budget was predicted to be increased undiscounted costs of approximately £40m per year by 2020 but no increase in 2030 following restoration of the maintenance budget.
With the importance to Transport Scotland of road safety, it was recognised that funding of winter maintenance would remain a high priority even at the lowest funding level considered (i.e. only a small budget reduction would be applied to winter maintenance if the overall maintenance budget is reduced by 40 percent). This study did not therefore predict any change in accident rates that may arise from a change in the level of funding of winter maintenance.
For structures, a Transport Scotland study in 2010 examined the effects of changes in the level of maintenance funding. The budget reductions (maximum reduction considered was 15 percent) were less than the overall cuts examined in this study but represented the likely effect on the structures maintenance budget following the subjective review of the current overall maintenance budget. This level of funding cut was not expected to lead to bridge closures but would increase the amount of routine maintenance required with the reduction in renewals maintenance. This may introduce difficulties for the 4 Operating Companies in future years. The effect on road users of the change in structures maintenance funding was not assessed as it was expected the reductions would have a small impact.
Transport Scotland uses condition data from the asset database with an asset valuation model to estimate the depreciation in the value of the trunk road network. The analysis for this study showed that even with retaining the 2010/11 levels of overall maintenance budget, the reduction in the undiscounted trunk road pavement asset value at the end of the 20 years analysis period was expected to be more than £480m. With the Scenario 2 funding (20 percent reduction in the overall maintenance budget) the effect was to increase the reduction to more than £540m and with the Scenario 3 funding the reduction in asset value by 2030 was expected to be more than £600m.
Maintenance operations contribute to the carbon footprint of the road network in a number of ways. The analysis in this study showed a predicted increase in the undiscounted costs of carbon emissions of £66m per year in 2020 if the current level of maintenance funding is retained. For the scenarios with 20 percent and 40 percent cuts in overall maintenance funding, the increase was predicted to reduce to £63m and £61m per year respectively. For Scenarios 1, 2 and 3 the increases in the undiscounted costs of carbon by 2030 were predicted to be £139m, £136m and £135m respectively.
Studies by Transport Scotland since 2008 into the road user perception of the trunk roads in Scotland highlighted a general concern for road users about the condition of the road surface. It is therefore expected that, with the predicted worsening in the overall condition of the network, users will continue to have the same level or more concern about pavement condition.
For the different funding scenarios, the increases in road user costs relative to the Base Case are most significant for the changes in vehicle operating costs due to changes in surface condition. For Scenario 3, in year 2020/21 there was a predicted annual increase of £62m from the undiscounted costs in 2010/11 but in 2030/31 this was reduced to £49m after improvements in network condition. Changes in all other road user costs were far less significant.
Overall there would be savings in electricity charges as lighting is reduced but these will be off-set by an increase in the number of accidents and the costs of those accidents. For Scenario 3, (40% reduction in the overall maintenance budget) the savings were not predicted to exceed £1.0m per year.

The overall outcome from the study is that with the predicted deterioration in network condition from the reductions in maintenance funding considered, the total road user costs were predicted to increase and exceed the discounted value of the total saving in the direct Transport Scotland costs, so the net effect was a reduction in the overall economic welfare for both maintenance funding Scenarios that include overall budget reductions, compared to the funding Scenario that retains the 2010/11 level of funding.