Whether she has made a comparative assessment of the relationship between switching off lighting on stretches of (a) motorways and (b) major trunk roads and trends in the level of accidents on these roads.
National Highways assesses the benefits and costs of any potential changes in lighting provision. This is in line with the design and appraisal standards set out in the Design Manual for Roads and Bridges, which ensures that road lighting is provided at a sufficient level to support road safety, whilst also being cost effective, energy efficient and not causing unnecessary light pollution. Where National Highways determines lighting should be removed, the implementation plan includes a full switch-off for an initial period of one year. This enables the collision and casualty rates to be monitored to determine if there is an impact on safety and if mitigating action is required.