The Scottish Government admitted yesterday that work to dual the A9 between Inverness and Perth will not be completed by 2025.
Transport Minister Jenny Gilruth said the target was "unachievable".
She said the government remained committed to upgrading the remaining single carriageway sections of the road to dual carriageway.
But she said the project had been hit by delays, highlighting the impact of the Covid pandemic, Brexit and the war in Ukraine.
The Scottish Government had committed to the project in 2011, when it was predicted to cost £3billion.
Over the last 10 years, work has been completed on two sections, totalling 11 miles of road - but about 77 miles of road remains to be dualled.
'Absolute' commitment
Ms Gilruth said the government's commitment to finishing the job remained "absolute" and that a new timetable for the project would be brought before the Scottish Parliament in the autumn.
Scottish Conservative MSP Murdo Fraser said communities had been waiting more than a decade for the government to fulfil its commitment.
And he warned that people would continue to die on the A9 until the road was made safer.
Scottish Labour MSP Rhoda Grant said missing the 2025 target was a "total betrayal to the Highlands".
SNP MSP Fergus Ewing said Ms Gilruth's statement would be met with "shock, incredulity and anger".
The BBC says the number of people killed in crashes between Perth and Inverness has risen to its highest level in 20 years, with 13 people losing their lives in 2022.
Extra road-safety measures
Ms Gilruth said £5million was being invested in extra road-safety measures, including enhanced signage and road markings, and electronic signs with safety messages.
She said the 2025 target for the project had always been an ambitious challenge which had relied on a range of factors.
Ms Gilruth said these had been "significantly impacted" by events, making the date "simply unachievable".
She highlighted that only one contractor had tendered for the work to upgrade the Tomatin to Moy section of the road.
This contract will now have to be retendered after it was decided that this bid did not represent good value to taxpayers.
- The government continues to come under pressure over its failure to dual the A96 between Aberdeen and Inverness.
The vast majority of people who took part in a recent poll said the road should be fully dualled from Aberdeen to Inverness.
The north-east public are getting impatient for a final decision on whether the vital link will ever be fully dualled.
The SNP promised over a decade ago it would dual the A96 between Inverness and Aberdeen by 2030.
However, this was thrown into doubt when the Scottish Greens were brought into government in 2021.
Following latest news of a delay in the decision, the Press and Journal asked its readers if the A96 should be dualled - and their response was clear.
Just over 1,300 votes were cast - and 1,221 said "yes" while just 87 said "no".