Ottawa could save money in the short term by following the international trend of rapid bus transit systems, according to one transit expert.

One hundred twenty cities worldwide, including Los Angeles, Guangzhou, China, and soon Gatineau will have adopted rapid bus service (BRT).

Ottawa's light rail is estimated to cost $2.1 billion, while a rapid bus system would cost around $233 million.

David Jeanes with Transport Action Canada said he expects the price tag for light rail to be more than it is now.

"Either the cost is too high, or they're holding to cost level and cutting too much from the project," he said.

Ottawa mayor Jim Watson has said repeatedly that the $2.1 billion for light rail is not the final number.

Construction tenders will be sent out in the fall, and a decision will be made on once they come back.

Ottawa city councilor Rick Chiarelli said that rapid bus service is still an option if the cost of light rail goes up.

"If we can't build a decent system for the money we have, we have to make a decision," he said. "If we have to make a decision will look at all the options and it will include that option."

However, Jeanes said that while the dollar value for bus service may be much lower, it might not address traffic woes downtown.

"The problem with BRT is when it concentrates everyone into a dense downtown area, it's the buses that create the congestion," he said.

Gatineau is currently building a 15 kilometre "Rapibus" system from northeast Gatineau to the downtown core.

With a report from CTV Ottawa's John Hua