America's 600,000 bridges are safe, but one out of every four US bridges needs to be modernized or repaired despite the best efforts of state and local departments of transportation. Making all of the necessary improvements today would cost at least $140 billion dollars. As the nation approaches the August 1 anniversary of the Minneapolis I-35W Bridge tragedy, the American Association of State Highway and Transportation Officials (AASHTO) today released Bridging the Gap: Restoring and Rebuilding the Nation's Bridges, a new report that outlines the critical challenges ahead.

Among the report's key findings:

-- Age - Usually built to last 50 years, the average bridge in this country today is 43; almost 20 percent of these "Baby Boomer" bridges are over 50 years old. As age and traffic increase, so does the need for repair.

-- The Price Tag - According to new data from the Federal Highway Administration, the cost to repair or modernize the country's bridges is at least $140 billion -- assuming all the bridges were fixed immediately.

-- Traffic Congestion - Many of the nation's large-scale bridges have become chokepoints on the country's freeway system and a drain on the nation's economy. The top 10 highway interchange bottlenecks cause an average of 1.5 million truck hours of delay each year.

-- Soaring Construction Costs -The costs of steel, asphalt, concrete and earthwork have risen by at least 50 percent in the past five years, forcing delays of bridge improvements and replacements. Nearly every state faces funding shortages that prevent them from the kind of on-going preventive maintenance, repair and replacement needed to keep their bridges sound indefinitely.

"This generation of baby boomer bridges is in need of significant repair or replacement. New technology can help us build bridges that are stronger and longer-lasting," said Pete K. Rahn, AASHTO president and director of the Missouri Department of Transportation. "Yet we are not seeing the kind of national attention or investment we need to address these issues."

Bridging the Gap also points to several solutions. Among them:

-- Increased investment in transportation at all levels of government - federal, state and local;

-- Support for a wide range of revenue options such as tolls, tax increases, annual road user fees, bonds or private investment;

-- Continued commitment to research and innovation;

-- Systematic maintenance to extend the life of bridges; and

-- Increased public awareness that bridges are vital links to business and communities.

AASHTO Executive Director John Horsley said, "Across the nation, state and local transportation agencies are struggling to keep our country's bridges safe, sound and fit for the future. A new generation of bridges must be built and Bridging the Gap points the way."