Tax dollars have built this nation's transportation infrastructure, from roads and bridges to airports and subway systems. Rent a car or truck for the day and you may think you're paying for your transportation, but that's only the vehicle — most of the thoroughfares you will travel were built and maintained by various taxes and fees.

Yet in the case of high-speed rail, conservative critics seem to think that government has no role in building, operating or promoting it. Never mind that modern, European-style rail systems offer the best chance to provide a safe, reliable, energy-efficient and environmentally friendly alternative to air travel between major cities, particularly here on the East Coast.

Later this month, it will be made clear just how far the U.S. has fallen behind other countries in high-speed rail development when China opens its 819-mile rail line between Beijing and Shanghai, a $34 billion project. The bullet trains will carry up to 80 million passengers a year at speeds of about 186 mph.

That's slower than a plane, of course. But add in the possibility — probability, really — of major delays associated with air travel, and the train is an attractive alternative, carrying passengers from a station just 31/2 miles south of Tiananmen Square to a station next to Shanghai's principal domestic airport. That is roughly the equivalent of Baltimore to St. Louis in about 41/2 hours and for about the same fare as a ticket on China's state-sponsored airline.

The project has not been without controversy. There is concern about corruption within China's rail ministry and whether a $300 billion expansion of the country's rail network has required borrowing too much money. The ministry has been forced to do some cost-cutting, including slowing down train speeds to reduce operating costs.

But that doesn't make the opening of the Shanghai line any less of a "Sputnik moment." The Soviet Union's space program had its problems as well, but that was not cause for the U.S. to ignore the implications of a rival nation's investment.

The U.S. cannot continue to be so dependent on passenger air travel, a weakness exposed on Sept. 11 but largely ignored since then. Travelers are crying out for a safe, convenient alternative, and the technology of high-speed rail has more than proved itself. But the start-up costs, particularly given the sorry state of existing U.S. passenger service, are considerable.

President Barack Obama has promoted high-speed rail, but the country's investment so far has been modest at best. Some states, mired in partisan politics, have rejected high-speed rail as an extravagance, but now leaders in those states face a possible voter backlash. Without Tampa-Orlando rail, for instance, possible relief for Florida's congested Interstate 4 is not even on the drawing board.

But others, including cash-strapped California, are moving forward despite the costs. They understand that high-speed rail is a bargain compared to the rising costs of highways and airport runways, a point reiterated this week by the mayors of San Francisco, Los Angeles, Sacramento and San Jose in a newspaper op-ed comparing the national high-speed rail movement to the building of the Interstate Highway System a half-century ago.

That's not to suggest all high-speed rail projects are prudent investments. Surely the most cost-effective strategy would be to bring the Northeast Corridor from Washington, D.C., to Boston up to China-like speeds first. As studies have noted, the circumstances and economics of the Northeast (large cities, congested airports, Amtrak's successful existing rail service) are optimal.

Perhaps, if there was at least one corridor brought to 21st century standards, high-speed rail's advantages would become all the more apparent to its critics. (Although visiting Paris or Tokyo could easily demonstrate the same thing.) A nation that can put men in space should have little trouble shuttling them across the country.

Lessening this country's dependence on fossil fuels, reducing greenhouse gas emissions, creating jobs and economic opportunities — the benefits of high-speed rail are numerous. The U.S. didn't stop building roads and bridges during the Great Depression, and it should not neglect its transportation system now. China's massive investment in high-speed rail ought to be seen as a challenge that America can't afford to ignore.