The speed limit on three stretches of the A47 could be cut to 50mph, with cameras installed to enforce the new restrictions.
National Highways is starting consultation over the changes, which it says are needed to improve safety.
The organisation had previously announced it wanted to cut the speed limit from 60mph to 50mph on the notorious Acle Straight near Great Yarmouth and on the section between Little Fransham and the Dereham bypass.
But National Highways has now announced it also wants to reduce the limit to 50mph between King's Lynn and Wisbech.
That would see the speed limit cut on the eastbound and westbound carriageways, between the junctions on the western side of Shoreboat Roundabout and the southern side of Pullover Roundabout on the edge of King's Lynn.
At Wisbech, the limit would be reduced on the eastbound and westbound carriageways, between their junctions with the eastern side of Wisbech Roundabout and the northern side of Lynn Road Roundabout.
Speed cameras would be installed to enforce the new 50mph limits on all the stretches of the road.
National Highways says the 6.8 mile Acle Straight had 54 crashes in which people were injured over five years, with 138 casualties.
On the 5.2 mile section between Little Fransham and the Dereham bypass, there have been 27 crashes causing injury over five years, with 41 casualties.
A National Highways spokesman said: "Safety is and always will be our number one priority, and that is why our ambition remains that no-one should be harmed while travelling or working on our roads.
"The proposals aim to improve road safety for all road users by introducing reduced speed limits, which we anticipate will reduce the frequency and severity of collisions."
People have 21 days to provide comments on the proposals, with details of how to do so at https://nationalhighways.co.uk/our-roads/east/safety-schemes-in-the-east-region/
Long-awaited work to dual two single carriageway sections of the A47, between Blofield and North Burlingham and from Easton to North Tuddenham, began this summer.
It is still not clear if or when work on a mooted revamp of Thickthorn junction - where the A47 meets the A11 on the edge of Norwich - will happen, with the scheme subject to a government spending review.
Chancellor Rachel Reeves announced in last month's Budget that plans to upgrade the A47 Vauxhall Roundabout in Great Yarmouth had been axed.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereLast Updated:
Report this comment Cancel