TORONTO - Ontario commuters will have to "do their part" to avoid gridlock during this summer's Pan Am and Parapan Games, which will bring hundreds of thousands of people to a region already struggling with congestion, the province's transportation minister said Tuesday.

Officials are banking on a 20 per cent reduction in traffic — through carpooling, transit use and other means — to keep delays at a minimum during the international competitions, they said, noting Vancouver reached a reduction of more than 30 per cent during the 2010 Olympic Games.

The province released traffic projections for the Toronto area based on what it expects to be the worst time: the afternoon rush hour on July 21.

Average traffic delays on Toronto-area highways at that time range from minimal if the 20 per cent reduction is achieved, to up to 20 minutes if it isn't.

Most affected, according to the province, will be the westbound Gardiner Expressway through the city's downtown, which could face five minutes extra delay at best and 20 minutes at worst.

No projections were available for city streets, on which many commuters rely.

Transportation Minister Steven Del Duca said he's "confident" commuters, visitors and those involved in the Games will adjust their travel plans.

But Michael Harris, the Progressive Conservative transportation critic, called the government's goal of reducing traffic by a fifth amounts to "wishful thinking."

"Businesses still need to operate, people still need to live and manage when these Games happen, and to just expect that for every five people, one needs to stay at home to alleviate traffic, is going to create problems," he said.

The province's transportation plan for the Games includes a 1,500-kilometre route linking venues, airports and the athletes' village as well as roughly 185 kilometres of new, temporary high-occupancy lanes on major highways and thoroughfares in the GTA.

The lanes will be open from June 29 to July 27 to all vehicles carrying three people or more, and from July 28 to Aug. 18 to all those with two or more people on board.

Provincial police said they will have an increased presence on the roads but aren't planning any specific checks to enforce HOV rules.

Transit services will also be increased, with service hours extended for some events, officials said. The cost of transit is included in ticket prices.

A route-planning app is in the works to help people find the most efficient way to travel during the Games and keep them informed of real-time traffic conditions, the province said.

Parking restrictions and road closures will be put in place near the venues and officials have said they were working to limit the amount of construction underway during the Games.

Efforts are also being made to ensure accessible transportation to events.

Officials also provided an update Tuesday on spending for the Games, saying the capital budget had decreased by $7 million due to savings on venue requirements, while the operating budget increased by $3.4 million to reflect an increase in the value of Games services supported by sponsorships.

Organizers say they expect to sell about 1.5 million tickets — worth about $40 million — but have so far sold some 350,000.

Most of the Games' $2.5-billion budget will come from the federal, provincial and Toronto governments.

The Pan Am Games will take place from July 10 to 26, with the Parapan Am Games to follow from Aug. 7 to 15.