Mayor Larry O'Brien unveiled his plans for managing Ottawa's traffic congestion Monday, a day after rival candidates in the election questioned his commitment to coming up with green solutions to the city's transportation issues.

O'Brien's platform calls for establishing an independent transit commission, entering into a private-public partnership to run ParaTranspo services and allowing motorcycles to use car-pool lanes.

He also called for improving routes to Toronto and Montreal and beginning plans to build a ring road to connect Highway 417 with the 416 through the southern corridor of Ottawa.

O'Brien said during a Sunday night debate that a ring road around the city would aid in reducing commute times for people living in Ottawa's outlying areas and relieving congestion in the downtown.

"One thing we can't do is ignore the fact there are a large number of people in this city who need their personal vehicles," said O'Brien. "Quite frankly, it's important that we keep our personal vehicles, so I'm going into the planning stage for a ring road."

O'Brien also said former Ottawa mayor Bob Chiarelli, now Ontario's minister of transportation, had in the past supported his idea for a ring road.

But Chiarelli told CBC News on Monday he had no recollection of doing so. "I didn't encourage or support a ring road in any way, shape, or form," he said.

Meanwhile, O'Brien's political opponents in the coming municipal election questioned the ring road plan at the debate, which was sponsored by Ecology Ottawa and a number of environmental groups.

Ring road will lead to sprawl: Watson

"Mr. O'Brien, who is all about roads, wants to build a ring road, a billion-dollar ring road into the Greenbelt with off-ramps, and push the urban boundary out farther and farther," said former mayor Jim Watson. "That is not acceptable to the vast majority of the people in this city."

Capital Ward councillor and mayoral candidate Clive Doucet also took on O'Brien's plans to build a 3.2-kilometre downtown tunnel as part of the city's proposed $2.1-billion light-rail transit plan.

Doucet said the plan was a "nightmare" that would be a financial loser for the city.

"We need to provide new revenue, new services," said Doucet. "East-west first, Carling and Innes Road and in the south, I will do it in four years, I will change the city by the end of four years, trust me."

Five other candidates — Cesar Bello, Andy Haydon, Robin Lawrance, Mike Maguire and Charlie Taylor — also took part in Sunday's debate. The municipal election is on Oct. 25.