Anglesey councillors have backed the building of a new bridge to help ease traffic problems over the Menai Strait.
The Britannia Bridge has seen traffic increase 21% in five years
They agreed to support option seven out of eight choices put forward, amid concerns about growing congestion.
The development, infrastructure, and resources committee was told the cost would be an estimated £120m.
However, any decision on which scheme would finally be adopted would lie with the Welsh Assembly Government, and not the council.
Engineers were asked to examine ways of easing problems across the Britannia Bridge carrying the A55 over the water.
Councillors threw their weight behind the option of a parallel bridge to carry eastbound traffic off the island with two lanes, and a footpath/cycleway.
It would be built on the eastern side of the current bridge. Abutments, or supports, would have to be constructed within a conservation area in the Menai Strait.
The bridge would have a speed limit of 60mph.
All the options in the engineer's feasibility study will be put out to public consultation.