Three years in the making, Wednesday's U2 concert at M&T Bank Stadium could attract a record crowd — along with gridlock in the streets — at a time when uncertainty over the NFL season leaves Baltimore looking for more ways to fill the stadium.

With an oversized stage in the round and fans on the turf, M&T's capacity will swell to 80,000 for the transcendent 360 Degree Tour concert. The crowd should threaten, if not eclipse, the stadium record of 75,000 who attended a 1999 HFStival in what was then called PSINet Stadium.

The first of two major events at the stadium this summer, the concert is designed to inspire cultural diversity and whet the city's economy. After you rock with U2, you can roll with Advance Auto Parts Monster Jam on July 9. An all-star lineup of 10,000-pound monster trucks, all with 1,500 horsepower and 66 inch tires, will treat Baltimore fans to an outdoor version of its long-running show in 1st Mariner Arena.

If the Ravens remain sidelined in the NFL's three-months-and-counting lockout, these special events will prove to be a reprieve, both for entertainment-seekers and for the city.

It is the Ravens' purview to bring events to the stadium, getting input from the stadium authority and city officials. Sometimes the Ravens serve as promoter of an event. Other times, they simply rent out the stadium.

"They are bringing events that once upon a time would have bypassed Baltimore," said Anirban Basu, chairman of Sage Policy Group. "Now they are stopping in Baltimore. …The U2 concert is more likely to attract more fans from long distance. And the more distance they're traveling, the more likely they will spend more money."

When the Ravens brought the Kenny Chesney country-music festival to M&T on a Saturday night in May 2008, it generated more than $1 million in tax revenue for state and local government. And that was with an attendance of 38,000, according to the study by Basu, whose company has produced several economic impact studies for the stadium authority.

The U2 concert can reasonably be expected to double those figures.

Mike Frenz, the executive director of the Maryland Stadium Authority, didn't hesitate when asked how many events he would like booked into the stadium in a given year, aside from Ravens' games.

"Ideally," Frenz said in perfect deadpan, "we would like to have 52 U2 concerts a year."

Since it's being held on a mid-week night, the only real concern is having 75,000 to 80,000 people converge on downtown for a 7 p.m. concert with ongoing road construction projects near the stadiums.

Bono and U2, mega-stars of music, already have played before a record 5 million fans in a tour of 30 countries across five continents. By late July, more than 7 million people will have witnessed the revolutionary show and paid in excess of $700 million in ticket sales, creating the top grossing tour of all time.

Roy Sommerhof, the Ravens' vice president for stadium operations, said he had preliminary discussions in 2008 to bring U2 to Baltimore. He just missed getting the Irish band a year ago. When schedules aligned this time, he had a big-time concert.

"It's been a lot of work," Sommerhof said. "But it's been good. A lot of times when you talk to promoters and want to put on events, they don't seem to happen. I'm happy to get this done."

Ravens president Dick Cass said his goal is to hold three or four significant events at the stadium, other than Ravens games. This year they should have three events besides football. It started with the NCAA lacrosse Final Four, an event that drew 116,000 fans to the stadium for three games in May.

Those three events take on added significance for the city. While negotiations to end the NFL lockout are ongoing, there is no guarantee a deal will be reached in time to save the 2011 NFL season. No one wants to see the venue, which was completed in 1998 at a cost of $220 million, sit idle for any length of time.

"The impact of each game is quite consequential," Basu said. "Typically, Ravens weekends are very good weekends at the Inner Harbor. Therefore, if there is a cancellation of eight regular season games or some fraction thereof, the economic impact is in millions of dollars, probably in tens of millions. And much of the impact is felt very locally in and around downtown Baltimore."

Basu conducted a 2007 study for the stadium authority on the economic impact of the Ravens and of M&T Bank Stadium, which seats just over 71,000. The study showed the Ravens pay $15.5 million to the state in sales and income taxes, support almost 400 jobs which generate nearly $300 million in wages, and account for $69 million in local business sales.

Other events are planned to make use of areas around the Camden Yards and M&T Bank complexes this summer. Upcoming are the African-American Heritage Festival (parking lots B and C at the stadium) on July 2-3, and the first Baltimore Grand Prix from Sept. 2-4, before the scheduled start of the NFL's regular season.