'The commission is not necessarily about getting people out of their cars, but getting people to think about other forms of transport,' said LCA director Luke Blair, who leads the account.
Planned topics for debate include congestion charging, climate change and comparing the UK's transport system with that of European neighbours.
'We will be looking at events where transport will be debated, such as the party conferences, to make sure the commission has a voice, ' added Blair.
As well as media relations, the brief includes liaison with other bodies in the transport sector, such as passenger groups. LCA will also bid to capitalise on the findings of the commission's research body.
Blair reports to chairman Peter Hendy, who has been tipped to replace Bob Kiley as the next Transport for London commissioner.
LCA replaces incumbent Martin Helm Communications.