The dualling of the last remaining stretch of single carriageway on the A11 in Norfolk and Suffolk has been further delayed.
Most of the A11 has been made into dual carriageway
A scheme in Cambridgeshire has taken priority over the A11 stretch between Thetford and the Fiveways roundabout.
West Suffolk MP Richard Spring said the announcement on Thursday over one of the country's most dangerous roads was "truly bitterly, disappointing".
The Highways Agency said it was still giving the road its full priority.
'Dice with death'
The East of England Regional Assembly (EERA) had to prioritise transport schemes in the region.
They opted for a guided transport scheme in Cambridge which was given the final go ahead on Thursday and awarded £116m.
EERA said it remained committed to dualling the A11 but gave priority to the other scheme because it could get up and running straight away.
Mr Spring said: "Having identified it as one of the most dangerous roads in the whole of England and the most dangerous road in the east of England, it has now been kicked into the long grass.
"This is a truly bitterly, disappointing decision for me who has campaigned for this... and for those who, every day, dice with death travelling on this congested road."
Suffolk County councillor Guy McGregor added: "We share Richard Spring's concerns about the timescales in which the scheme can be implemented.