"This will improve the safety of this key freight route connecting Hawke's Bay and Manawatū and provide safer passing opportunities," Partridge said.
Setting the new completion date of the fourth quarter of this year, NZTA had worked closely with stakeholders of the project, including the Central Hawke's Bay District Council, to ensure they had "visibility" of the revised timeframes, Partridge said.
The NZTA says a review of the crash history of the area for 10 years, until 2019, revealed 23 crashes had been reported.
No fatalities were recorded but there were three serious injury crashes and nine minor injury crashes.
The majority of crashes were loss of control and or head-on, with more than half being on bends.
Analysis found the "overwhelming" percentage of lost control on a bend suggested drivers were travelling too fast for the road environment.
"This could either be due to driver error or that the bends are out of context with the road segments either side and drivers are being 'caught out' by the twisting terrain," NZTA staff said.