Basic Washington Truth: The Beltway is terrible, and trucks, not cars, make it that way.

But like all Basic Truths, this one can use a test. So on a recent rainy Tuesday, I hopped aboard an 18-wheeler to see how the truck-vs.-car Beltway war looks from the highest seat on the road.

The driver I hooked up with was John Chamberlain. He has driven a rig for Giant Food for 12 years, and he is one of the best in the business. In 26 years of professional truck driving, covering three companies and more than 2 million miles, John has never had an accident.

We decided to drive once around the Beltway, counterclockwise, into the teeth of morning rush hour. John picked me up with a sigh of air brakes at the Cheverly Metro station. We pulled onto the Beltway at the U.S. 50 interchange in Lanham.

8:06 a.m., coming down the entrance ramp: "Most of the trouble with rush hour is that people are impatient," John declared. "They're gonna get there. They don't care how."

I ask John to define a bad driver. "Put it this way," he replies. "Everybody speeds once in a while. A bad driver speeds all the time."

8:13 a.m., Baltimore-Washington Parkway exit: A car is being tailgated by a second, which is being tailgated by a third. All this is taking place in the second lane from the left. But John Chamberlain is camped in the second lane from the right. "This is the lane I always use," he says. "You avoid the people getting on and off, and you avoid that," pointing at the tailgaters.

Then he adds: "Really all it takes is a good attitude, and like my father always taught me, good horse sense." John's horse sense has him going 52 miles an hour, and keeping six truck lengths between his 42-foot-long rig and the car in front of him.

8:20 a.m., New Hampshire Avenue exit: Backup forming. All four lanes start slowing to a crawl. Just as John is about to catch up with the pack, a black Pontiac changes lanes and whips in front of him. The Pontiac gains about three feet in the process.

"We've got bad truck drivers; don't think we don't," says John, as we inch along. "But truckers never change lanes unless they have to. It's dangerous. It isn't worth it."

8:41 a.m., Rock Creek Park: "Here's my philosophy," says John Chamberlain. "The main thing is, don't get upset. When somebody does something crazy, and you say, 'You S.O.B., the next time you ain't gonna do that,' then you're right down to their level."

Without signaling, a blue Plymouth swoops right across John's bow and into his lane. John doesn't say a thing.

8:45 a.m., Old Georgetown Road exit: A green Volkswagen that has seen better days is immediately in front of John. He drops back slightly so that he is eight truck lengths behind the VW, not six. "That car is much more likely to blow a tire than most of them," John explains. "And if he blew a tire, and I was six lengths behind him, I'd be involved. I wouldn't be able to avoid him."

More Chamberlain philosophy: "I care if I cause an accident. I care if I cost the company money. I care if the boss gets a letter that says I'm the worst driver he ever saw. A lot of guys don't care. I care a lot."

8:53 a.m., George Washington Memorial Parkway: John Chamberlain does not own a car. When he isn't driving a Giant truck, he drives his own pickup. Once in a while he drives his wife's car, "but I don't like the visibility." In the minute it has taken John to tell me about his pickup and his anticar views, his eyes have not strayed from the road.

9:18 a.m., approaching the Woodrow Wilson Bridge: It's obvious from a mile away that traffic is at a standstill because the drawbridge is up. However, John starts braking as soon as he sees trouble, not once he's on top of it. "When you carry 70,000 pounds, you learn to do that," he says.

9:36 a.m., Branch Avenue: More philosophy: "You've got a great responsibility out here. You take one of these tractors, you might have a $200,000 responsibility. That's a big responsibility."

Then why are so many trucks at the center of so many accidents? "Those are just the ones you hear about," says John Chamberlain. "I know I sound defensive, but you can have 100 car crashes, and one involving a truck, and which one do you read about in the paper the next morning?"

9:46 a.m., Cheverly Metro station: There have been no close calls, no stomping on the brakes, nothing that even jostled the 5,000 pounds of plastic milk cartons in the back.

"I hope you've learned something," says John Chamberlain.

I have. I've learned that all it takes to be a safe driver -- regardless of what you're driving -- is to anticipate trouble, obey the law and pay attention. Or as John Chamberlain put it, in a final burst of philosophy: "Trucks can't solve the Beltway problem. Cars can't do it. We've all got to work together."