questionText: To ask the Secretary of State for Transport, what estimation she has made of the percentage of traffic on the M25 that is related to Heathrow Airport.
answerText: The Department does not have robust observed estimates for the proportion of traffic on the M25 that is related to Heathrow Airport, as it is difficult to disaggregate this from available data. For example, passenger data does not translate to an estimate...
heading: M25: Road Traffic