The Government's announced €150 million to upgrade 15 kilometres of road in Co Sligo.
The Collooney to Castlebaldwin N4 route has been described as "notoriously dangerous" by the Transport Minister.
The stretch of road has no safe overtaking opportunity for 90% its length.
Nine people died on the route between 1996 and 2018, while there were 10 serious and 81 minor accidents in the same period.
Cabinet approved the funds for upgrades to the road this morning.
Announcing the funding, Minister Shane Ross said it's not acceptable that the section of road has been described by a county coroner as "possibly the worst road" in the country.
He said: "Over the decades there have been many serious collisions and fatalities in this area.
"There are families and communities in the North West region who are still suffering the loss of loved ones who have died on this road."
He added: "Good roads can save lives. On behalf of this Government and local representatives, I’m pleased that this road will now be rebuilt to a modern standard."
He also suggested the improvements will lead to a better quality of life for those living in the North West regions of the country.