Fifty years ago this week, a speech to U.S. governors dramatically changed the future of America. It envisioned a vast network of high-speed expressways, criss-crossing the nation. Two years later, in 1956, Congress approved the nationwide grid of superhighways called the Interstate Highway System, and the first spade of dirt was turned in rural Missouri. These interconnecting ribbons of concrete are now seen as a blessing by some and a curse by others.

Vice President Richard Nixon delivered the speech to the governors, working from President Dwight Eisenhower's notes. Ike, as he was called, missed the occasion because of a death in his family. An audio recording of Nixon's remarks could not be found, but here's part of what he said in 1954.

"Let us look at the highway net of the United States as it is," he said. "It is obsolete because in large part it just happened. It was governed in the beginning by terrain, existing Indian trails, cattle trails, and arbitrary section lines. It was designed largely for local movement in an age of transcontinental travel. Every year there's a wastage of billions of hours in detours, traffic jams, and so on, amounting to billions of dollars in productive time."

As a solution, President Eisenhower proposed a $50 billion highway program to be completed in just 10 years. As it turned out, the final piece of the system as planned and funded, an astounding tunnel and bridge project called The Big Dig in Boston - opened just this year - 50 years, not 10, after the Nixon speech.

Richard Weingroff, an informal historian at the Federal Highway Administation, says two experiences ignited Dwight Eisenhower's interest in superhighways. One, while he commanded the Allied push into Germany during World War II, was a close-up look at Adolf Hitler's super-fast Autobahn freeways. The other, 25 years earlier, was a frustrating drive across the United States in an Army convoy.

"During this convoy tour, the participants experienced everything that was wrong with the nation's highways: dirt roads, mud roads," Mr. Weingroff said. "Some roads were so bad, they were called 'gumbo' because the tires would sink so far into the ground. Some vehicles blew off of cliffs. The bridges were too narrow, too weak. He saw how bad the roads were, and how vital they were to the nation's economy, to its defense."

President Eisenhower and supporters in Congress envisioned that the new insterstate highway system could be funded largely by tax revenues from the sale of gasoline - a kind of user-fee. But to Mr. Eisenhower's dismay, Congress in 1955 buckled under pressure from truckers, oil companies, and other highway interests. It defeated every bill to get the new interstate system up and running.

Over the winter, they began to realize that they had killed the goose that lays the golden egg, that was going to benefit them greatly, even if gasoline taxes went up a little bit.

And so what many credit as history's most ambitious engineering project got underway. The final tab for 64,000 kilometers of divided, high-speed highways 50 years later: more than $130 billion.

Writer Dan McNichol, who has written several books about Boston's Big Dig, took a broader look the interstate highway system in a book entitled The Roads That Built America. He notes that wide interstates are safer, straighter and more level than most conventional roads and have become a powerful economic engine.

"For all practical purposes, the warehouse of America today is an 80,000 pound [36,000 kilo], 18-wheeler truck hauling materials along the interstate system," he said. "After [the terrorist attacks of] 9-11 [2001], Federal Express, UPS [United Parcel System], the United States Postal Service unloaded their planes - all of them grounded - rushed their fleets of trucks to the airport, took the precious cargoes out of the bellies of the planes - like blood and medicines - and moved them along the interstate system. So for those two or three days after the attacks, we kept moving."

Susan Tolbert, the curator of an exhibit called "America on the Move" at the Smithsonian National Museum of American History in Washington, notes that interstate highways have many critics, especially in urban areas, where it was thought a superhighway would bring prosperity into town. Instead ...

"It has cut through communities," she said. "You ride above the communities, or you have big sound barriers that cut you off. So you don't get a sense of what it's like, visually or dynamically."

Cities like New Orleans and San Francisco successfully fought plans to bulldoze historic neighborhoods for freeways. So did local activist Sammie Abbott in the Washington, D.C., area. He passed out signs reading, 'White man's road through black man's home.' The campaign halted Interstate 95 in its tracks in the heart of Washington.

Other observers say interstate highways spoiled the special regional flavor of places like rocky New England and saucy Louisiana and the dusty Old West. Writer John Steinbeck wrote a scathing critique of his first drive on an interstate.

"Instructions screamed at me from the road: 'Do not stop! Maintain speed.' Trucks as long as freighters went roaring by, delivering a wind like the blow of a fist," he wrote. "These great roads are wonderful for moving goods but not for inspection of a countryside. When we get these thruways across the whole country, it will be possible to drive from New York to California without seeing a single thing!"

Loved or despised, ever-widening interstate highways have become a fixture across the American landscape. Reports say Congress is close to giving states the authority to levy tolls on selected lanes of previously free interstates as a way to hurry impatient drivers past traffic bottlenecks and raise money for even more high-speed roads.