The DfT devised a scheme to cut administration expenses by placing its payroll, finance and personnel services all in one site in Swansea.
The strategy was designed to save the organisation £57 million but the committee estimates it will cost £82 million, because it was rushed through and the IT system was unstable when it was switched on - issuing messages to some staff in German.
Edward Leigh, chairman of the Committee of Public Accounts, said: "This is one of the worst cases of project management seen by the committee.
"The department knew it was pushing things with such a tight timetable but, without robust challenges to such a risky strategy, ploughed on confidently. The result was lamentable."
But the DfT has promised to rectify the situation. A spokeswoman said: "The department recognises the problems this project has encountered and will be responding to its recommendations in due course, with an update on our progress.
"It is important to remember that all of the costs in the report are estimated projections to 2015. We are committed to finding additional savings over this period, to improve value for money.
"We are also pursuing additional uses of the system, which are expected to generate further savings, so reducing the estimated net cost reported by the committee. Progress is being made in stabilising the current system in the meantime."
DfT lambasted for shared services disaster
The Department for Transport (DfT) planned and implemented its shared corporate services project with stupendous incompetence, according to the House of Commons Public Accounts Committee.
