Jurassica would see a semi-subterranean cavern built in Portland within a 40m (132ft) deep limestone quarry.
Science journalist Mike Hanlon, behind the idea, said the road and rail network was "not fit for purpose".
It is reached by a single carriageway causeway road from Weymouth. The nearest train station is in Weymouth.
If it goes ahead, it is expected to be completed by 2019 or 2020.
Jurassica said an estimated 500,000 to 600,000 visitors a year were expected.
The attraction will house fossils, interactive displays and robot swimming plesiosaurs in an aquarium.
Mr Hanlon said it would enable visitors to feel they were "in a different world".
At a meeting on Friday night held to discuss the plans with residents, Mr Hanlon said the "main logistical issue" with the project was traffic.
A Heritage Lottery Fund (HLF) funding bid for £16m is due to be submitted by the charity on 29 November.
The outcome of the bid is expected in April.
Mr Hanlon said further funding would also be sought from the Wellcome Trust - an independent charity funding research to improve human and animal health.
The project was awarded £300,000 in July from the Local Enterprise Partnership for a feasibility study.
A charitable trust has been formed for the museum with all profits from Jurassica going back into the charity.
Sir David Attenborough is patron of the project and the Eden Project's Sir Tim Smit is its trustee.
This article was amended on 29 September 2015 after a clerical error by the Jurassic team led to incorrect projected visitor numbers being stated in a report by Weymouth and Portland Borough Council.
A charity behind a project to build an £80m underground dinosaur museum on the Jurassic Coast in Dorset has commissioned a £30,000 traffic study.