The National Institute for Transport and Logistics has called for an independent evaluation of the LUAS project and the proposed plan for a Metro in Dublin.
The Institute, which is part of the Dublin Institute of Technology, has said the original cost of the LUAS was €288m but the system is now expected to finally cost around €800m.
In its audit of Ireland's transport system, the institute also raised concerns about the value for money of subsidising regional air routes. It said the proposed break-up of Aer Rianta - which it described as 'superficially attractive' - raised questions about financial viability of Cork and Shannon airports.
The NITL said the large investment in roads could have implications for the future of some inter-urban rail lines and regional air services.
