The North York Moors National Park looks set to block council plans for a 400-space park and ride facility on the outskirts of Whitby.
The authority fears a park and ride site would harm the environment
Scarborough Borough Council says the site is the best available and would ease gridlock in the town centre.
At peak holiday times almost 1,000 cars an hour descend on Whitby in search of one of the town's 3,000 parking spaces.
The park and ride plan is on land controlled by the park authority, which has recommended refusal.
The chief planning officer has told the authority, which meets later this month to discuss the issue, that the development would have a negative impact on the existing exposed and undeveloped landscape.
However, the scheme has the backing of the borough council, Whitby Town Council and many businesses who say traffic congestion is harming the local economy.