There certainly doesn't seem to be any explanation for it within the documentation the RPA have produced to date nor is there any opportunity to object to it on their heavily loaded Questionnaire. I would also be pleased to see an explanation of the traffic displacement figures they have produced. Looks like they are making it up as they go along, and twisting the statistics to suit their preferred option. No surprises there. We need to look at reducing traffic levels overall, not just in the park.
Demand always grows to the supply of roads.
The more roads we provide, the more cars there are. The fewer roads there are, the fewer cars there are. Examples that demonstrate this are the M25 and Hammersmith Bridge closure. Cars also kill around ten people each and every day in the UK through accidents. We must reverse global warming and pollution else the UK will be gripped by further floods.