The Department for Transport has not completed any estimates specifically on the effect of construction and use of bicycle lanes on air pollution. But we recognise that encouraging car users to switch to alternative, more sustainable, forms of transport like cycling can generally have both health and carbon reduction benefits as well as improving local air quality.
When we appraise cycle schemes for funding, we apply WebTAG unit A5-1. This appraisal looks at outcomes only and does not consider impacts during the construction phase of a scheme. Where a scheme includes shifts away from mechanised modes and changes in congestion levels, we use marginal external costs, including air pollution. This is done at an individual scheme level and reported in the appraisal of each case; therefore no holistic study has been undertaken. This appraisal does not take account of potentially complex changes to motorists behaviour (such as speed and route choice) resulting from the introduction of cycle lanes.
Transport for London state that during the construction phase some localised short-term slight impacts on local air quality can be expected from the use of plant and vehicles. However, contractors are required to minimise dust and emissions to air and comply with the Greater London Authority and London Councils’ Control of Dust and Emissions from Construction and Demolition Best Practice Guidance.
Transport for London undertake air quality modelling to ascertain the impacts during operation. Schemes such as the East-West Cycle Superhighway show that the likely impact of the introduction of cycle lanes and changes to the road layout on air quality ranges from adverse to beneficial. The study shows that changes in traffic will redistribute emissions across the study area but will not increase overall emission levels.