Demand forecasting for South Dock Bridge

Steer was appointed by the London Borough of Tower Hamlets to explore the feasibility of a new or replacement bridge for pedestrians and cyclists over South Dock on the Isle of Dogs.

The feasibility study included technical feasibility and initial design work to decide on the appropriate design of the bridge, as well as forecasting demand for pedestrian and cyclist movements.

We developed a bespoke distribution model to forecast demand. The purpose of the model was to identify the optimum alignment for the potential new bridge and to scope the required width of the bridge to accommodate forecast demand on each alignment.

The model base year was 2014, and the forecast years were 2020, 2031 and 2031+. The model was built using Census travel to work data to build an origin-destination matrix either side of South Dock for pedestrians and a wider catchment for cyclists. The model was then validated using local survey data to confirm that the base year outputs were realistic.

There were several components to forecast increases in demand in future years. These were committed new developments, induced demand from the provision of an improved link, switching local public transport trips to walking or cycling, and general growth in population and trips.

Successes and outcomes

The model outputs identified a combination of two bridges across South Dock would best cater for the predicted demand by distributing demand evenly across South Dock. It also provided a recommended width for the bridge based on Transport for London design guidance for pedestrians and cyclists. The model also provided an estimate of cumulative time savings for bridge users in order to calculate a benefit:cost ratio to make the case for the new bridges.