The 2019 Australian Infrastructure Audit found that the performance of urban roads and urban public transport in Adelaide is a key challenge for South Australia.

The Audit estimated that the cost of delay on Adelaide’s urban transport network was $1.4 billion in 2016 and would grow to $2.6 billion in 2031 in the absence of investments or other changes beyond those already funded.

The major public transport destination in Adelaide is the CBD, with most public transport use being on buses. Public transport use in Adelaide is significantly lower than in Sydney, Melbourne and Brisbane. In Adelaide, the proportion of passengers using public transport for journeys to work is just under 9%, compared to 11.6% in Brisbane, 15.6% in Melbourne and 22.8% in Sydney.

Adelaide’s recent employment growth has been centred on the inner and middle suburbs, whereas population growth has been strongest in the middle and outer suburbs. Existing public transport services do not support urban density. A continuation of existing land use patterns will result 
in greater reliance on and use of private passenger vehicles, in turn leading to further road congestion and delays at the expense of economic efficiency.