BOSTON -- For years, Boston drivers have enjoyed a certain notoriety for their approach to getting about here. Impatient, fast and ruthless, they give many visitors the impression that driving in Boston is a souped-up, real-life game of bumper cars.

But this native can testify that Boston drivers get a bum rap, that their reputation as kamikaze is unwarranted. The primary offenders seem to be mostly young men who come here from New York and New Jersey to attend one of the many fine colleges. They think that they can perform like stunt drivers because they are young and far from mom and dad.

The genuine Boston driver is swift but sure, in a hurry, of course, but aware that it is bad form to hit anything. I like to think that we Boston drivers are organisms who have evolved along with our environment, developing the lane-hopping, heel-toeing, traffic-dodging skills vital to survival in a constantly shifting terrain of missing street signs, high-speed rotaries (traffic circles) and short, narrow, one-way streets.

Now comes "The Big Dig."

That is what everyone calls a $5 billion highway and tunnel project that is to remake the face of downtown and force us to figure out new shortcuts to Logan International Airport, the North End and elsewhere.

The Massachusetts Department of Public Works (DPW) says the plan will put 15,000 people to work, clean the air, unsnarl daily gridlock and leave the city with more than 20 acres of new park land when the existing artery is demolished.

DPW deals in superlatives, saying the dig is the biggest highway project on the books, the biggest public works project in New England history, will create the nation's largest interchange, will replace the nation's most congested and dangerous section of interstate highway. Unsaid is that this is expected to cost more than $600 million a mile.

Most of the local business and political establishment is gung-ho. Only a few people are opposed, calling it a monstrous throwback to the 1950s that will bury the problem, not solve it. A lot of people simply quibble about different elements.

The Big Dig has three major parts:

A new Central Artery. The John F. Fitzgerald Expressway, alias Interstate 93, is a six-lane elevated highway that was built in the 1950s to move 75,000 vehicles a day and now gags on 190,000. Because it is due to start falling down and does not meet interstate standards, it will be replaced by an eight-lane tunnel from South Station through Chinatown and the financial district to Quincy Market and North Station.

A new Harbor Tunnel. Interstate 90, having crossed the country from Seattle, dead-ends at the Central Artery in Chinatown. From there, drivers often can see Logan across Boston Harbor and also watch their flights leave before they can drive to the airport. The new four-lane tunnel is supposed to have high-occupancy vehicle lanes to whisk cars, buses and car-pool vans to Logan and points north.

Scheme Z. At the northern end of the Artery project, I-93 heads north across High Bridge over the Charles River, bound for Canada. At the river, however, it must connect with Route 1, currently accomplished by dumping all traffic into a high-speed "weave" many stories above ground. DPW wants to build an option known as "Scheme Z" -- a vast, 10-story spaghetti bowl of ramps, loops and bridges connecting I-93, Route 1 and many local roads, all while crossing the river.

The Big Dig is the brainchild of Frederick Salvucci, who does not even drive and was state transportation secretary until the Dukakis administration expired last week.

Salvucci made his reputation as an opponent of highways and advocate of mass transit. So a lot of people wonder why he would make the capstone of his career a giant highway project.

Salvucci said the point is to deal with a rotting roadway and save the regional economy by making sure people can get to Logan. Critics speculate that Salvucci actually hopes to foul auto traffic so thoroughly that people will be forced onto mass transit.

Whatever the plan's merits, it has become a test of political faith to support snagging federal funds to pay for it. Former House speaker Thomas P. "Tip" O'Neill Jr. labored mightily through the late 1970s and early 1980s to keep the project on the books, and the Massachusetts delegation continues the tradition.

At ground level, though, tough questions persist. Most of the criticism is being leveled at Scheme Z. The city of Cambridge, home to the state's new governor and House speaker, is opposed, along with the Sierra Club and others, who say it will entomb the river's banks in shadow.

Some people also ask why the state is going through the ordeal of tunneling under the downtown without bothering to include a direct railroad link of North Station with South Station, the northern terminus of Amtrak.

Engineers say that is impossible: The underground right-of-way is too narrow to add rail lines and the grades too steep for trains anyway. Instead, planners promise to study building yet another harbor tunnel to carry rail traffic from South Station to Logan and northward.

All that remains before the big diggers can commence are final approvals expected from the Environmental Protection Agency and Federal Highway Administration in the next few months. Planners say the whole thing should be finished by 1998 and last well into the next century.

By then, Boston drivers yet unborn will be figuring out how to get around it.