One hundred million euro has been set aside to improve accident blackspots on roads around the country this year.
However Transport Minister Leo Varadkar said only half of the 60 upgrades will be carried out during 2012 - with work starting on the remaining 30 only "if and when" the money is there.
The National Roads Authority (NRA) will select which projects get the go-ahead.
Mr Varadkar said the schemes would support work levels equivalent to around 1,200 jobs.
"This funding will be used to improve safety at major blackspots, such as removing bad bends or hazardous conditions," he said.
"In a number of cases the funding will be used to remove bottlenecks and tackle congestion.
"Given that Exchequer funding is currently so limited, my main priority this year is to maintain roads and prioritise safety projects, followed by road improvements, and finally by new projects."
Hundreds of other small-scale projects are also to start this year involving new road surfaces, minor safety works and improved signage.
Work is also to begin on the N5 Ballaghaderreen Bypass, Co Roscommon, the N7 Newlands Cross upgrade, south Dublin and the N11 Arklow to Rathnew route, Co Wicklow.
Fred Barry, chief executive of the NRA, said: "We are delighted that even during these constrained times we will be able to carry out essential local improvements and tackle some of the worst safety challenges on the legacy road network."