The dualling of two single-lane bottlenecks on the main road between London and Hastings has been recommended for government funding.
Improvements to the A21 were discussed at a meeting in London on Friday.
Conservative MP for Tunbridge Wells, Greg Clark, said he was pleased that a commitment was made on securing funding for two parts of the road.
They are the stretches at Castle Hill and between Kipping's Cross and Lamberhurst in Kent.
Much of the A21, which passes through Kent and Sussex, is single carriageway.
The call for dualling was discussed by the South East England Regional Assembly's Regional Transport Board.
"Having the A21 as a dual carriageway from the M25 to Scotney Castle is great news for road users in the area," said Mr Clark.
He said it would create good access for a new hospital at Pembury, as well as environmental benefits with congestion being relieved in Tunbridge Wells and Southborough.
"I have written to the transport secretary today [Friday] urging him to fund these vital improvements," added Mr Clark.
The schemes have been recommended for funding from 2010-11.