The main road between London and Hastings is "amazingly disjointed", according to an MP calling for more of the road to be dual carriageway.
A bypass is being built to take traffic away from Lamberhurst
Archie Norman, the MP for Tunbridge Wells, is to meet with the Highways Agency and local residents to discuss the next stage of changes to the A21.
Much of the road is single carriageway and it passes through a number of small towns and villages in Kent and Sussex.
Mr Norman said he wants the A21 to be safer to drive on.
The Conservative MP - who was the party's transport spokesman during William Hague's leadership - will chair a meeting to discuss future development of the road on Thursday evening.
The Highways Agency will meet local residents and councillors at a school in the Kent village of Lamberhurst.
Building of a bypass around Lamberhurst begun in 2003.
One section of dual carriageway is to be reduced to single lanes
Mr Norman has said he wants the entire A21 to eventually be dual carriageway and the section between Lamberhurst and Kipping's Cross is to be discussed at Thursday's meeting.
The MP said: "We've got a bypass at Lamberhurst and we're going to get a stretch done at Castle Hill.
"But amazingly it's all disjointed and in between there is lots of little single carriageway highway.
"It's very dangerous and with this stretch I'm determined to get it improved, to get it dualled, as soon as possible."
Although Mr Norman and other MPs, including Hastings MP Michael Foster, have called for more of the A21 to be dualled, one section of dual carriageway is due to be reduced to one lane later this year.
The dual carriageway section at Flimwell, on the Kent-Sussex border, has seen more than 35 serious crashes since 1999, with 11 people killed.
The Highways Agency announced in March the stretch of road would be reduced to one lane each way by the end of the year and the speed limit cut from 70mph to 60mph.