A county council has said it will not be taking disciplinary action against four staff members over the spiralling bill for a public transport scheme.
Costs for the Fastway bus service have spiralled
Costs for the Fastway bus project linking Crawley, West Sussex with Horley, Surrey, via Gatwick Airport soared by over £6m to nearly £30m.
West Sussex County Council (WSCC) said it accepted mistakes were made and management systems were faulty.
But it said officers were not to blame for the project's increased costs.
WSCC carried out an internal investigation into possible disciplinary action against the four members of staff.
It concluded there was no case for taking action against any individual.
The internal probe followed an independent audit carried out by East Sussex County Council (ESCC) into the cost increases.
ESCC concluded West Sussex had shown a pattern of "ineffective accountability, complacency, ineffective risk management and a lack of clear ownership of the financial management responsibilities".
Liberal Democrats accused the Conservative cabinet of putting inexperienced staff in charge of the multi-million pound scheme.
On Thursday, WSCC chief executive Mark Hammond, said: "It must be understood that officers of the county council were not to blame for the external factors which led to increases in the project.
"These were due to issues including delays in work by the public utilities and increased costs within the construction industry."
He said WSCC had accepted the recommendations of the external auditors over the way major contracts should be managed in future.
"The county council has been as open and transparent about the Fastway issue as possible," said Mr Hammond.