Throw away your T pass! Buy a second car! The Big Dig is at least half open and - $14.6 billion boondoggle though it is - it's a boondoggle that works. Indeed, it's a boondoggle that inspires.

Saturday night saw the inauguration of yet another (ho hum) miracle of roadway engineering. Following on the heels of January's unveiling of the connector between the Mass Pike and the Williams Tunnel, Turnpike boss Matt Amorello and Big Dig officials over the weekend shuttered the northbound lanes of the Central Artery (the southbound Big Dig doesn't open for another year). In their place they gave us the Liberty Tunnel and Zakim Bridge.

So here I am, traveling north into Boston at 7:40 a.m. yesterday - a time that places me deep in the horrors of rush hour. Traffic? What traffic? In less than two minutes, I'm on the other side of downtown.

And while I'm zooming along, I offer up a silent thank-you on behalf of the people of the towns north and south of Boston.

Thank you, residents of Framingham, Worcester and all points west. And thank you, too, citizens of East Boston, Revere and everywhere else along Route 1. It's your tolls, deposited at the Sumner and Williams tunnels, the Tobin Bridge and along the Turnpike, that make sure drivers from live-free-or-die New Hampshire all the way to sandy Cape Cod enjoy a smooth, uninterrupted and, most importantly, free, commute.

Let me repeat that: Free.

Your generosity, so gladly given, is much appreciated.

In any event, back to the Big Dig.

Like every boy who grew up playing with trucks, I had followed its progress with much anticipation. So on Sunday, hearing that the new road had opened a day early, I shouted: ``Come on, kids. We're going for a ride.''

``Where are we going?'' asked the youngest.

``Nowhere,'' I said. ``We're just going to drive on a road.''

My oldest daughter fixed me with a baleful look and in the kind of cutting voice that only teens can muster, repeated my words back to me: ``We're going to drive on a road.''

``Arrgh,'' she said, slumping back in her seat.

``This is the road we've all been waiting for,'' I said. ``The one that will eliminate traffic jams.''

We then turned on to the new highway at Morrissey Boulevard and for the next hour sat in traffic. By the time we made it to the mouth of the tunnel, my kids were no longer speaking to me. We crawled through at 10 miles per hour.

At least with the old elevated highway, we had a view.

``Don't worry,'' I assured the children. ``It's just opening-day jitters.''

There is a proposition that every driver but me is an idiot. Sunday was its proof. Tunnel gawkers were slowing down to take photos. Motorists were heedlessly cutting across four lanes of traffic to make their exits. The first day saw seven accidents.

But despair not. For I have driven the new road many times since, including both rush hours, and Sunday's problems have not been repeated. Indeed, the genius of the design, hard to understand when looking at maps and graphics, becomes apparent as one drives its length.

Where once traffic to the airport had to travel into Boston, now it exits well south of town to the Williams Tunnel. And while it is disconcerting to have new lanes pop up to one's right and left while in the Liberty Tunnel, these are entrances carrying traffic from other places that are not forced into an instant merge, a la the old Fitzgerald Expressway. In fact, traffic from the Sumner Tunnel never merges into the tunnel at all, traveling on its own lanes up to and (eventually) over the Zakim Bridge.

Ah, the Zakim Bridge. Even if the tunnel were a failure, even if traffic were a nightmare, the new bridge would make everything all right.

By now, we know it well from a distance: A gossamer spider's web soaring over the Charles River. But for the motorist, the experience is different. As one emerges from the subterranean depths, it's like entering a cathedral. Churches for ages have tried to combine structure and light to somehow move the spirit. The Zakim bests them all. And at night, surrounded by blue light shimmering along feathery white cables, it's hard not to gasp.

I know, it's only a highway. My kids already have pronounced it ``boring'' and I suppose that the rest of us too will eventually become inured to the whole thing, no longer seeing the marvel in our midst. But marvel, nevertheless, it is.

Tom Keane can be reached at tomkeane@tomkeane.com.