For goods vehicles, the Department draws upon the Airports Commission’s assessment of road freight numbers as published in their Appraisal Framework Module 4 - Surface Access Freight Impacts Study.
In October 2017, the Department published within its Updated Appraisal Report: Airport Capacity in the South East, details of the estimated surface access trips for both highway and public transport trips for each of the airport expansion options as inputs to its non-flight carbon assessment.
Details of the estimates for annual highway trips for the Heathrow Airport options are set out in the following table:
Annual highway trips (car and taxi) by passengers and employees at Heathrow, DfT17 central forecasts (millions)
Highway vehicle trips
LHR Extended Northern Runway
LHR Northwest Runway
As specified in the Airports National Policy Statement, it will be for an applicant for development consent for the Heathrow Northwest runway scheme to submit a surface access strategy to the Planning Inspectorate alongside their application.