Three days before the May 2 race, the Pennsylvania Department of Transportation will shut off direct access from the Fort Duquesne Bridge to the Fort Pitt Bridge and close the ramps that lead south from Fort Duquesne Boulevard and the 10th Street Bypass. Just in time for Pittsburgh’s usual event-packed spring and summer.

It is best to hear from an optimist first.

Larry Grollman, the race director of the Pittsburgh Marathon, says he thinks people will pay attention, plan ahead and make accommodations.

Both Grollman and Jeanne Pearlman, executive director of the Three Rivers Arts Festival, are anticipating the new traffic patterns with the fortitude you’d expect from people who plan huge events. They know the meaning of the term "big headache."

The marathon expects to draw as many as 20,000 onlookers to Point State Park. The marathon also expects a 10 percent increase in participants.

That same afternoon, two to three hours after the race winds down, a Sunday crowd will be leaving Three Rivers Stadium after the Pirates’ game against the Colorado Rockies.

For this first phase of road construction, the link between the Fort Duquesne Bridge and the Fort Pitt Bridge will be severed. To get from one to the other, drivers will have to get off the Fort Duquesne Bridge, wind around Downtown and get onto the ramp to the Fort Pitt Bridge at Commonwealth Place. Even if things go as smoothly as possible, it won’t be pretty.

The ramifications of detouring and the closing of lanes starting Thursday have been anticipated for months. PennDOT, the Port Authority, the Stadium Authority, the Pittsburgh Downtown Partnership, the city Parks and Recreation Department, the Three Rivers Arts Festival, the Pirates and Penguins and the sponsors of a spate of local events have all met and made plans to mitigate the expected summer imbroglio.

The importance of getting home quickly is not lost on the Pirates. They have printed brochures to help. They are sending them to season ticket holders and will make them available at the ballpark. They will also direct people to listen to Pirates broadcasters for access and egress directions after the game.

Vic Gregovits, the Pirates’ vice president of marketing, said people could also get suggestions by calling 321-BUCS.

On June 4, when the Three Rivers Arts Festival opens for 16 days, it will not have Commonwealth Place to kick around on as usual. The food booths won’t be set up on the sidewalk this year but in the grass of the park. This will give pedestrians a wide berth of safety from traffic that will be detoured onto Commonwealth off Fort Duquesne Boulevard.

The arts festival’s printed program will be available in boxes throughout the Golden Triangle and include maps and suggestions for getting around. Downtown workers can carry them home the evening they intend to come back Downtown for the festival.

"There will be an impact on the festival," Pearlman said. "But can we say something here about maintaining your sense of humor? These bridges are an enormous source of pride for us. This is an investment in our future."

By Independence Day, when the city is inundated with 100,000 people for the annual fireworks extravaganza, the construction crews will have passed the deadline for snagging a $574,000 incentive from PennDOT to be finished. But Mike Radley, the city’s program director for special events, is planning for a wilder-than-usual Sunday, just in case.

"It will be difficult, but we’re going to make it happen," Radley said. "Our hope is that people will plan ahead. But there is no easy way to do this. The reality is, we have to suffer for a while. It’s the price of progress."

Each year on the night of Independence Day, 60,000 to 70,000 people fill Point State Park. The North Shore is also lined with people, and the Three Rivers Stadium parking lot is usually filled -- the Pirates play an afternoon game that day. The bridges congest with people stopping and getting out of their cars, and people blanket the shorelines.

The potential of the rivers for mass transit shines brightest at a time like this.