New homes can be built in Fontwell before road improvements are completed.
Councillors have agreed to overturn a restriction on the 400 dwelling development on land east of Fontwell Avenue.
A government inspector, who approved the scheme in 2017, ruled improvements to the A27/A29 roundabout (Fontwell Avenue/Arundel Road) had to be carried out before any house-building work began.
But Arun District Council’s development control committee has agreed with the developer, Dandara, that 150 of the homes can be occupied before the roadworks are finished.
David Easton, a council planning officer, said the delay would add 31-34 vehicle movements an hour through the junction.
“Given the existing traffic flow through the junction this equates to an extra one per cent increase in traffic flows,” he said.
It would lead to a 26 second delay in northbound journeys but no delays in other directions.
Walberton, Eastergate and Slindon parish councils opposed the change.