Tall commercial buildings (roughly buildings 30 storeys or more) have become an increasingly controversial topic in planning and land use development circles. This research allows the economic impacts of tall buildings tobe effectively considered and evidences the importance of locating tall buildings with careful consideration of transport provision and impacts. Tall buildings provide an opportunity for increased density in key districtsin urban areas, particularly around transport nodes where available land is often scarce. In these areas building up may be the only way to achieveincreased densities. A case study was undertaken in London, comparing output and productivity in three scenarios in 2026: (1) A base scenario, depicting expected employment growth, density, and resulting output as specified by London Plan projections of scale and distribution of employment in 2026; (2) A tall buildings at transport nodes scenario, where tall buildings accommodating 20,000 employees are added at four key transport nodes in London, expected to have available capacity with the opening of Crossrail.Total employment in London in 2026 stays the same as in the base scenario; shifted employees moving to the four tall buildings nodes are distributed evenly across the Central London boroughs containing the tall buildings;(3) A tall buildings not at nodes scenario, where tall buildings of the same scale are added in four areas not at key transport nodes. Again, totalemployment in London in 2026 remains the same as the base, with an even reduction of employees across the relevant boroughs in London. These scenarios are modelled at small scale geographies (Railplan zones, there are about 1,100 of these in London), where employment and output per zone is calculated in the base case. Then, the resulting changes in effective density (taking account of employment density and job accessibility) per zone are calculated with the tall building scenarios. Agglomeration elasticities are applied to estimate the change in output per zone based on the change ineffective density. Total output for London can then be summed for each scenario, and, as total employment is the same for all scenarios, productivity can be calculated showing the impact of the change in density allowed by tall buildings. Early results suggest that the tall buildings near transport nodes scenario creates significant external agglomeration benefits, while adding tall buildings at non-transport nodes creates external agglomeration disbenefits. Future research plans are described. For the covering abstract see ITRD E145999
Abstract