A new report has revealed that car travel times in the most gridlocked parts of Brisbane are about to get a lot worse if drastic measures are not taken.

Car travel times in the most gridlocked parts of Brisbane will more than double by 2031 without transport investment, while congestion could cost the economy more than $53 billion, a new report from The Infrastructure Australia audit has revealed.

The report, titled Our Infrastructure Challenges, will was launched by Prime Minister Tony Abbott and Assistant Infrastructure Minister Jamie Briggs in Sydney.

The report says car travel times in the most gridlocked parts of our country are expected to jump by at least 20 per cent if there no measures to boost capacity or curb demand.

“In some cases, travel times could more than double between 2011 and 2031,” the report says.

The report proposes introducing dedicated lanes for carpooling, buses and trucks.

The audit estimates Australia’s population will grow to 30.5 million in 2031, with the biggest four cities growing by around 45 per cent.

The report predicts public transport demand will more than double in Melbourne, and jump by 55 per cent in Sydney, and nearly 90 per cent across other capital cities.

“Unless peak period passenger loads are managed and capacity is increased, commuters in all capital cities will see more services experiencing ‘crush loadings’, where peak demand exceeds capacity,” the report says.

The Federal Government’s top infrastructure advisory body also predicts demand for flights will double and additional airport capacity will be needed in Sydney, Brisbane, Perth and Melbourne.

It also says increased private and public funding will be needed to maintain and grow infrastructure networks.

The Government will invite submissions on the audit, with a 15-year infrastructure plan expected to be released later this year.