A road development has been branded a waste of money by protesters.
Members of the A27 Action Group claim Highway Agency proposals for work between Southerham and Beddingham, near Lewes, including a proposed flyover, will not solve congestion problems.
The plans, which could cost up to £16 million, have been put on display at Lewes Town Hall.
Alan Chapman, chairman of the A27 Action Group, said: "They have misunderstood the problem and therefore have misunderstood the solution. The problem occurs only at peak times.
"All we need to do is cream off 15 per cent of that peak-hour traffic using a combination of buses, car sharing, flexible working, school buses, the railway that runs alongside and home-based working.
Until these measures have been tried and tested, why waste money on a "solution" that will only make the problem worse."
Mr Chapman said the congestion problem could be further increased by the creation of a new town between Ringmer and Uckfield, as revealed by The Argus on Saturday.
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