A vital scheme to improve safety and congestion at a notorious accident blackspot is back on track.

Improvements to the A23 between Handcross and Warninglid, near Haywards Heath, were thrown into doubt when the cost of the scheme rocketed from £40 million to £69 million.

But the South East England Regional Assembly's transport board has now decided to keep the project in its programme for 2011.

Extra funding will now need to be secured from the Department for Transport if other schemes across the South East are not to be sacrificed.

The board ruled that the A23 work was too important to drop and has asked the Highways Agency be proceed.

It is hoped that upgrading the road from two to three lanes will slash accidents by a third and cut traffic jams.

The report to the transport committee said: ìThere are significant proposals for both housing and economic growth in the immediate area, which will prove difficult to unlock without upgrading the route.î It also emerged that any delay to the decision would add another £900,000 to costs.

In a letter to the DfT, Councillor Nick Skellett, chairman regional transport board, wrote: ìThe board looks to the Department for Transport to make an appropriate contribution towards the cost increase from either its own national programmes or the programmes of other Government departments.

ìI must emphasise to you the board's concern that failure to provide additional funding, over and above the region's existing Regional Funding Allocation, will have an adverse impact on the region's ability to deliver the agreed regional programme.

ìThe A23 Handcross to Warninglid, in particular, is a scheme whose delivery has substantial national benefits.

ìThe scale of these benefits serve to highlight the importance of the Department for Transport making a contribution towards the cost increase from sources other than the existing regional allocation.î The rising costs of the Chichester bypass are also to be discussed by the regional transport board.

It has emerged the scheme is projected to come in at £192 million, £55 million up on the original estimate.

The future of the crucial road improvements will be discussed on May 16.