Business leaders want to charge drivers for using roads to pay for an overhaul of transport and stop a "stranglehold" on the south east Wales economy.
Cardiff Chamber of Commerce says the road systems in the area are too congested and that has a detrimental impact on business.
It fears the Welsh economy will fall behind other parts of the UK unless something is done to improve roads.
It estimates £500m is needed to improve the infrastructure.
Traffic gridlock after two fatal crashes on the M4 in two months has highlighted the issue of the transport infrastructure in and around Cardiff and the south east of Wales.
Cardiff Chamber of Commerce said charging drivers is the only way a major road expansion programme, which would include a new dual lane ring road around Cardiff and increasing the capacity of the M4 could be paid for.
It said its 1,400 member businesses in and around Cardiff and the south Wales valleys see congestion as the number one issue affecting their trade.
Increase capacity of M4 at Newport and jcts 29-32, Heads of the Valleys, Cardiff airport link, Cardiff East
Invest in rail and bus infrastructure
Road pricing to spread traffic load more evenly across day
Bus lanes inc A470 Cardiff-Pontypridd, A48 Culverhouse Cross-Cardiff; A469 Caerphilly-Cardiff; A48 Cardiff-Newport
Park and rides east, north and west of Cardiff
Longer, more modern and frequent trains; more trains to airport
Source: Cardiff Chamber of Commerce's Transport Forum report
Chief executive Russell Goodway said: "It's (the traffic congestion) a stranglehold on the economy at the moment - the closure of the M4 on two occasions in recent months cost local businesses millions in lost productivity and just failing to get their people into work.
"Transport infrastructure improvements are never going to be paid for without some form of road charging - we have to accept it's not a case of "if" but "when".
"Leadership is needed from government and local government to start the debate.
"Unless we change things, we will have grid lock in Cardiff at peak hours within two or three years."
The chamber's report also looks at opening up bus "corridors" on main routes, improving rail services and the links to Cardiff International Airport and ports.
Mr Goodway said millions of pounds were needed to pay for the infrastructure to be improved.
"The estimates carried out by Cardiff Council three years ago put a price tag of around £500m on what needs to be done," he said.
"There's complete acceptance that the money needed to put those solutions in place will not come from traditional sources that is tax payers funds.
Mr Davies said congestion was a problem in Cardiff and Newport
"Therefore we are going to have to turn to the private sector to generate the money.
"As much as we would like it to replace road fund licenses and fuel duty we need to make sure south Wales stays ahead of the game.
"Other cities and other regions of the UK are already looking at road pricing schemes and if Wales falls behind then the economy of Wales falls behind," he added.
But Friends of the Earth Cymru has warned about the effects on the environment of improving and expanding the road network and said more roads were "not the answer".
It said transport was one of the significant contributors to climate change.
Director Gordon James said: "Building roads will inevitably generate more traffic and more carbon dioxide.
"Building roads is yesterday's solution - it does not make much sense in the age of climate change."
He added that the M4 could be "upgraded sufficiently to ease congestion" rather than building the M4 relief road.
But Sewta, the transport alliance of local councils in south east Wales, said "major and urgent steps" were needed.
Chairman Tom Williams said: "The chamber says we need to move the debate on road user charging from 'if' to 'when and how'. Sewta endorses that view.
"The majority of drivers support the principle of road user charging, but only if the money raised is used to benefit public transport and things really do get better."