Byers announced he was resigning as Secretary of State to the Department of Transport, Local Government and the Regions (DTLR) following months of controversy over his policies and internal wrangles.
Prime Minister Tony Blair immediately announced a major shake-up, which included splitting up the DTLR, creating a new Department of Transport, under Darling. Local Government and the Regions has been handed to Deputy Prime Minister John Prescott.
As Darling settled into his new role, the Association of Car Fleet Operators (ACFO) fired off a letter calling for him to concentrate on five key areas and calling for a face-to-face meeting to hammer out policy.
The letter said: 'We look to you to be the instrument of much-needed change. We would welcome an early meeting with you and senior officials to discuss how we might work better together across a whole range of policy initiatives.'
ACFO said cornerstones of policy should be honesty, realism about the importance of the car in the modern economy, determination to act instead of talking, action to clear congestion and real investment to spend some of the £180 billion promised for transport in the Government's 10-year transport plan.
It added: 'We never managed to make much headway with either of your predecessors, but I would hope that we would have the opportunity to meet with you, given that you 'only' have to deal with the transport portfolio now.
'Fleet operations and, indeed, all aspects of business travel obviously form a vital part of that portfolio.'
The British Vehicle Rental and Leasing Association added to the pressure, with John Lewis, director general, saying: 'What we need, and the country needs, is a strong individual with the moral courage to take difficult decisions, such as rescinding the legislation that is allowing Ken Livingstone to introduce an appallingly complicated and bureaucratic congestion charging scheme in London.
'The new minister must also have a clear vision of the transport needs of the UK and find the ways to meet them. No spin, no fudge, no politics, just a clear, well-communicated vision and a sense of urgency, for we can wait no longer.'
Lewis also attacked the role Byers had taken in transport, adding: 'Frankly, he was a disaster that actually happened. His inability to even begin to deliver on the Government's 10-year transport plan all add up to one of the most inept, pointless and misjudged ministerial appointments ever.'