Recommendation 27

National Highways retains responsibility for addressing air quality issues on the parts of the Strategic Road Network that pass through urban areas. It told us that, in setting its measures, it needs to ensure it does not do anything that displaces traffic onto other roads, which would shift where exceedances occur and risk displacing heavy traffic onto roads managed by local authorities.44 It told us that it manages these risks both at the national level, through working with the seven sub-national transport bodies, and at a local level, through considering signage options and working with local authorities where sections of the strategic road network are in a clean air zone.45 However, UK100, a network of local government leaders, told us that many of their members have found that “effective engagement with National Highways is difficult, and they struggle to find out information from them or gain tangible support from National Highways for air quality action.”46 The potential impact on local roads is considered as part of the assessment of the viability of air quality measures on the strategic road network, but as National Highways does not currently publish the criteria by which it judges viability, it is not possible to confirm the extent to which these considerations have affected decision making.47