Richmond Hill has fallen 18 places down the Department of Infrastructure's list of accident blackspots since work on it was finished.
In response to a question for written answer in the House of Keys, Minister David Cretney revealed the improvements were already having an effect on road safety.
He was quizzed over the cost of the works by South Douglas MHK Kate Beecroft, who also wanted to know the figures for the Ballakillowey Roundabout in the south of the Island.
Mr Cretney said Richmond Hill cost £2.8 million, while the Ballakillowey Roundabout cost £275,000.
In his answer, Mr Cretney defends the Richmond Hill scheme, saying it cost almost £169,000 less than originally estimated.
He says the new road layout means the hill has already dropped from being the worst accident location on the Island down to 18th position.
Mr Cretney says in the three years before the work Richmond Hill had a number of serious accidents, including one death.
He warns the true position in terms of safety can only be established after three years of accident data, but is confident it will fall outside the top 30 accident sites.