59.The Department’s approach to analysing the environmental impact of transport schemes was praised by the NAO. It said that DfT “actively considers the impact of each infrastructure project on the environment through a robust and well documented appraisal system […] recognises the opportunities available to improve the environment, and allocates some funding to take advantage of these.” We noted in an earlier section, however, some specific concerns about the Department’s WebTAG project analysis programme. The NAO highlighted a further potential gap, stating:
Concerns have been raised, both by external stakeholders and some within the Department, regarding the assessment of impacts and opportunities on a cross-project basis.
60.The NAO explained that the Department’s approach was to assess each project’s likely impact upon the environment, with decisionmakers provided with information to help them decide whether that was acceptable. It added, however, that
the number of transport projects carried [out] in the UK creates a risk that the cumulative impact of several projects reaches a level that would be unacceptable if applied to a single project. It is unclear how this risk is managed by the Department […] responsibility for the national cumulative impact of all 127 projects lies with the Department.
In response the Department said:
When we consider large programmes of infrastructure investment, like the Road Investment Strategy, we conduct programme level economic assessments. As part of this we assess the total impacts of those schemes, including their environmental impacts, such as carbon dioxide emissions, air quality pollutants and noise. The Road Investment Strategy Economic Assessment is available online.
But the NAO told us that, although this analysis included the monetisation of carbon and air quality impacts,
this is high level and notes that it “does not include all the ‘non-monetised’ impacts which are important for the VfM [Value for Money] process”. Therefore there is an opportunity to ensure the full range of environmental impacts have been fully assessed on a cumulative basis. This is particularly important where impacts cannot be fully mitigated, such as through destruction of ancient woodlands.
61.The structure of the Department may provide one explanation as to why cumulative impacts are not considered by default. The NAO said: “It is unclear how fully environmental impacts are considered in strategic decisions across the transport network as a whole, both between transport modes and across the boundaries of local and national interests. For example, we found that board level discussions take place regarding key environmental issues, but it is unclear how effectively these are linked to the strategic discussions and decisions elsewhere.” The division of the Department by transport mode also meant, the NAO said, that
[the] assessment of solutions to a problem are typically a choice between options within one sector, rather than between modes of transport or problem focused solutions combining a number of smaller schemes.”
62.The Department’s positive approach to sustainability is demonstrated through its robust project appraisal system. If such decisions on the environmental impact of individual projects are made in isolation across multiple projects, however, they may lead to an aggregate impact that cannot be fully mitigated. The Department could do more to assess in detail the full cumulative impact across its transport projects, so that it can state definitively whether natural capital is being at least maintained. This has particular implications for assets such as ancient woodland, which cannot be easily or instantly offset through new planting. It might consider taking a similarly broader view of matters by looking for solutions to project issues outside individual transport sectors. We recommend that the Department put in place a detailed cumulative impact assessment, including non-monetised impacts on biodiversity and landscape, of all its projects. We recommend also that the Department consider whether key environmental issues are considered sufficiently below board level, particularly when decisions about the environmental impact of a particular project are being considered.
90 National Audit Office, , May 2016, Areas, p12
91 National Audit Office, , May 2016, Areas, p12
92 , para 3
93 National Audit Office, , May 2016, Areas, p12
94 National Audit Office, , May 2016, Key messages, p3
95 National Audit Office, , May 2016, Areas, p18
1 August 2016