The bridge, scheduled to open around 2015, would be the fifth span between St. Louis and its Illinois suburbs, and siphon Interstate 70 traffic from the 45-year-old Poplar Street Bridge that carries three interstates over the river and is prone to backups.
The bridge would be toll free -- a concession by Missouri, which in recent years had insisted that motorists pay for using the span. Illinois had rejected the idea of tolls, saying they would be a burden on the tens of thousands of Illinoisans who commute to work in St. Louis and its Missouri suburbs.
The plan also allows for the bridge, designed to be two lanes in each direction, to be expanded by a lane each way.
Missouri would pay about $88 million for construction and cover any cost overruns. Illinois would contribute $313 million because most of the work on interstate connectors would be done near East St. Louis, Ill. The federal government is to pay $239 million.
Before signing the deal Thursday, Illinois Gov. Rod Blagojevich said the bridge is "the right thing to do" to ease the burden on commuters. Missouri Gov. Matt Blunt said the new span will "help tie these two states together."
"I think this was a fair deal," said Jay Hoffman, a Democratic Illinois state representative who chairs that state's House Transportation and Motor Vehicles Committee. "I didn't know that this day would ever happen, but we all came together. The proof is in the pudding, not the process."
The announcement was a major breakthrough for both states, which for more than a decade had agreed that a new bridge was needed but could not resolve differences about the scope of the project and how to pay for it.
The project consistently was downsized even as traffic across the river continued to mushroom. A few years ago, the bridge was designed to be eight lanes and cost $1.6 billion. Officials said that span -- which would have been called the Ronald Wilson Reagan Memorial Bridge -- would become a "signature bridge" and possible tourist draw near St. Louis' towering Gateway Arch.
The price of an eight-lane span eventually was scaled back to $910 million but still went nowhere as both states haggled about how to pay for it. The project later was downsized to a range of $410 million to $450 million, which would have paid to add a "coupler" bridge of four westbound lanes parallel to the existing Martin Luther King Bridge. That bridge would have been renovated to carry three eastbound lanes.
Both of those projects would have rerouted I-70 from the congested Poplar Street span -- used by more than 120,000 vehicles daily -- and carry the traffic north of downtown St. Louis.
While car traffic has grown, capacity across the river has dwindled from 22 lanes in the 1960s to about 16 now. By 2020, the St. Louis Chamber and Growth Association has predicted that rush-hour travel time in the area could double to three hours from the current 90 minutes.
Officials said the design work on the new bridge would begin immediately, with construction beginning as early as 2010 and lasting four to six years.
On the Net:
Illinois Department of Transportation, http://www.dot.state.il.us
Missouri Department of Transportation, http://www.modot.org
Mississippi River Bridge Project, http://www.newriverbridge.org