Congestion charges, also known as road tolls, could help make the Toronto-area economy more productive, says a new report on the city's competitiveness.

About 71 per cent of the region's population is dependent on the automobile. Not only is that costly for commuters, traffic tie-ups hurt the economy, says the Paris-based Organisation for Economic Co-operation and Development.

Traffic delays represent "a direct hit on productivity, especially in certain economic sectors dependent on rapid delivery (e.g. retail, logistics and food)," says the 213-page review of the region's economy released Monday during a global cities forum at the Toronto convention centre.

Economists in the past have estimated that traffic costs the GTA more than $2 billion in lost productivity.

"A congestion charge has proven to be an effective tool for reducing traffic congestion in a variety of metropolitan regions," the report says, suggesting tolls could be applied on the 400-series highways and other major arterial roads.

Mayor David Miller said he supports tolls being levied region-wide to raise money for expanding transit. But Metrolinx, the regional transit planning authority, has been wary about climbing on board.

"Metrolinx decided to look at its financing strategy in a couple more years, once it's started building ... and then look at financing the next wave," Miller said.

Tolling "will be something that has to be considered, as long as it's done on a regional basis. I think that's the way you have to look at that kind of issue, particularly because the congestion is often worse immediately outside Toronto than it is inside Toronto."

Between 1995 and 2005, the Toronto region posted lower growth in economic output and lagging labour productivity compared with other cities studied by the OECD.

While the city has renowned educational and research institutions, that has not translated into positive economic indicators such as patents awarded and growth in high-tech employment, the report said.

It calls on government to expand innovation initiatives such as the MaRS medical research centre.

Miller said investment in cities is vital to encourage innovation.

"There's tremendous research happening there, but the innovation doesn't often enough lead to job creation."