The owners of three detached homes in Hove have agreed to sell up if architects win permission for a four-storey block of flats on the site.
The scheme is attracting opposition from neighbours who fear the 42-flat building on the half-acre site would harm the road's appearance.
The owners of two large two-storey homes and one bungalow in Dyke Road have agreed to sell up if the project by Totem Architecture is successful.
Parents walking with their children to nearby Windlesham School think they will be in danger from increased traffic.
At least 17 of the Dyke Road flats would be low-cost housing.
But protesters feel Totem's proposals would "degenerate" the Hove Park area.
Lyn Thomas, who lives next door to one of the houses planned for demolition, was approached but refused to sell.
Mrs Thomas, 43, moved in two years ago and walks her four-year-old son, Jake, to Windlesham School each day.
She said: "The traffic is already almost intolerable here but having 42 homes replacing three will make it even worse."
Karen Patching, of nearby Barrowfield Drive, also fears for the safety of her daughters, Honor and Lara.
Mrs Patching, 39, said: "This scheme would look completely out of character."
Totem Architecture, based in Western Road, Brighton, was formed three years ago to plan, design and fund property developments.
Director Adrian Black said: "Being flats this will be a more dense development than detached houses but we have made a big effort with the design of the scheme."
When approached by The Argus, people living in the homes earmarked for demolition said they had been advised by Totem not to comment.
Residents have until Friday to contact Brighton and Hove City Council with comments.
A public meeting to discuss the scheme will be held in the hall of the Church Of The Good Shepherd in Dyke Road next Tuesday, February 10, from 7.45pm.
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