When did driving a car turn into such an indignity, such an ordeal?

When did you first notice that half the traffic jams you crawled through had no apparent cause whatsoever?

When did you start asking, over and over: "Where the hell are all these people going?"

What was the first Saturday you decided to drive down to Potomac Mills and buy a bookcase at Ikea, and I-395 was jammed, the wise guys weaving in and out, trucks moaning and slobbering 11 feet behind you, a feeling that you were not so much driving as being driven, trapped and out of control at the same time, like having a heart attack in the middle of a prison riot?

When did you start getting out of the car with an adrenalin hangover, a kind of smoggy tingle in your body that lingers for hours?

When did you start looking at your suburban dream of a house and wondering if it was worth the driving you have to do?

Something has changed.

People hear about a rash of shootings on Southern California freeways and they say: "Sure."

The president of the United States gets stuck in a half-mile backup on the Beltway on Oct. 8 -- Columbus Day, a holiday -- and nobody pays much attention.

We are all prisoners of the Q/K curve now. It is changing us. There is no changing back.

The Q/K curve, or one of its bullet-shaped cousins, is what traffic engineers draw on scratch paper when you ask them about the terrible thing that is happening to our fundamental American right to Get in the Car and Go, to our Ozzie-and-Harriet lives as we think we should live them.

The Q/K curve has nothing to do with traffic jams caused by collisions, flat tires or even the couple who made love in the parked car in the Rosslyn tunnel on I-66 last year, further slowing the traffic that was already too slow for them. These jams we can do something about. The Q/K curve explains traffic jams that happen for no visible reason.

There are more and more of them.

"Just before exit to Md. 193 traffic is very heavy, stop-and-go with speeds around 5-10 mph. There are no visible problems," say the Beltway notes of a researcher at the Metropolitan Washington Council of Governments.

And: "One mile before Md. 414 ... traffic comes to almost a complete stop... . There is no visible reason for slow down."


"This is speed," says Thomas Deen, who is executive director of the Transportation Research Board at the National Academy of Sciences. He leans over the coffee table in his office and draws a line on a piece of graph paper. "And this is volume." Another line, crossing the first and signifying the number of cars.

The makings of a graph, a member of the Q/K family (Q standing for vehicles per hour, K for vehicles per mile).

Deen draws a line that signifies a pleasant procession of 200 cars an hour down each lane of a graph-paper freeway at 60 miles an hour. This is service level A, as the engineers say. When the line gets out to a volume of between 500 and 1,000 cars an hour, heading for service levels B and C, his pen curves downward. Speed declines as traffic gets thicker. Deen keeps drawing. It looks as if he's drawing a bullet lying on its side, a U/Q curve, technically, with U standing for speed. The pen moves toward the tip.

"Now we've got 1,800 vehicles per hour," Deen says. "There are two seconds between each car."

They are going, say, 30 to 35 miles an hour, about 100 feet apart, service levels D and E. "Traffic moving well on Route 50," you can imagine the radio saying. Indeed, the system is working at maximum efficiency -- throughput has been optimized, as the engineers would say.

But traffic is much like life itself. Just when it gets optimized ...

Deen's pen hits the tip of the bullet. We're past 2,000 cars per hour, per lane. Here the graph gets peculiar. The pen goes around the tip and draws the other half of the bullet.

"Before, we were losing speed but gaining volume," Deen says. "Now we're losing speed and losing volume." Service level F, stop-and-go becoming bumper-to-bumper.

How can this happen on a freeway where everything is perfect?

The problem is the physics of the Q/K curve. At service level E the slightest perturbation -- a slow truck, somebody parked on the shoulder -- can turn flow into sludge the way the supersaturated solution in a chem lab dumps solids on the bottom of the beaker when you tap it with a little glass rod.

But why? Here the engineers start talking about shock waves, and asking if you can read the formulas for fluid-dynamics equations.

Assume a perturbation: You see a lost dog on the median and you think it's going to run in front of you. You hit the brakes. The guy 75 feet behind you hits his brakes. The guy behind him doesn't get his foot on the brakes until he's 50 feet away from a crash, so he brakes more sharply, which means the guy behind him not only brakes but swerves into the next lane, igniting another firestorm of brake lights. We now have a "backward forming wave" that will result in cars coming to a dead stop, causing a "frontal stationary wave" for the people driving up to it, to use the language of Adolf D. May, author of "Traffic Flow Fundamentals."

We also get the forward recovery wave that happens when the dog trots away and you accelerate. Just as people brake faster and faster as the space closes in front of them, they have to accelerate slower and slower to open it back up again. This causes more waves, such as a forward-forming wave, a rear stationary wave and a backward recovery wave, all of them increasing or decreasing in amplitude according to the laws of fluid dynamics.

You, meanwhile, have long since forgotten about the dog, and as you pull into your parking space you hear about the jam on the radio.

You say: "Good thing I left early." And as everybody you messed up behind you crawls out of the jam, they say: "What the hell was that all about?"

It was about mathematics. And that, as hipsters used to say in the '50s, is a rumble nobody can cool.

The Q/K curve describes the absolute limits we are reaching in a country where we will soon have one car for every adult; where there are more households with three cars than there are with none; where people spend more money on personal transportation of all kinds than they spend on food or on housing. We are no longer up against bad driving or bad engineering. In 1987, two-thirds of interstate highways in American metropolitan areas were congested during peak hours. By 2010, even if we make all planned improvements, Northern Virginia freeways will be teetering on the wrong side of the Q/K curve during 84 percent of their peak hours, according to the Council of Governments. And peak hours are expanding. Non-work-trip driving is growing much faster than work-trip driving. Weekends are getting almost as dense as weekdays as two-earner families hit the road to do errands and have fun. On a Saturday last June, 159,996 vehicles traveled I-95 past Rte. 214 in Maryland, only 7,000 less than on a Monday.

Something has changed.

Freeways once meant freedom. They were begun with the $25 billion National Interstate Highway and Defense Act in 1956, in fact. They were another weapon in the Cold War, a way not only to move troops and supplies, but to build the good suburban life that would prove to the world that the American way was Number One.

Expressways! Superhighways! Parkways! If you're old enough, try to remember the first time you drove on one, the great creamy futuristic flow of them. Auto writer Brock Yates wrote that freeways were "an existential limbo where man sets out each day in search of Western-style individualism." We act as if this were still possible, as if cars still meant freedom, even as they destroy it.

The Cold War is over. There aren't going to be any new highways for a while. In the past 20 years, highway travel has risen 69 percent and capital spending on bridges and highways has fallen 38 percent. We're out of money and rights-of-way. And we have a huge supply of lawyers, city planners, politicians, lobbyists and not-in-my-backyard suburbanites to make it legally and politically impossible to build new roads. We built them to cause development, they say, so we can stop development by not building them. Except that the development goes on anyway, and what we get is more traffic jams. We once built highways the way the pharaohs built pyramids. Now we've stopped.

Screaming at Honda Blonde

Morning. The Beltway. By the time you get to the Silver Spring exit you feel the traffic congealing, phlebitis of the freeway, infarct of the interstate, arterialsclerosis heading toward the tip of the Q/K curve.

"... traffic moving well on the Outer Loop," the radio says.

Indeed, you're going 30 miles an hour. In the mirror you see part of a trailer truck -- it's that close. Ahead of you is a Cherokee with a bumper sticker reading "I'd Rather Be Sailing." You're a lot closer than you'd like -- no point in keeping any distance or one of the new breed of highway slalom racers will angle right through it, that streaked blond in the Honda Accord, for instance, with a look of frantic entitlement on her face as she does that floaty shuttling thing back and forth across the lanes, pure Type A, fueled by match-grade control-freakery. And, you notice, she is putting on lipstick while she drives -- a gesture that used to seem the ultimate in something or other until you saw a guy reading while he drove.

People haven't always driven like this, have they?

You are frightened, you can feel your heartbeat and a cold burn of anxiety around your lower ribs. America may have the lowest highway fatality rate in the world, but recent research in California shows that even as fatalities decline, bad traffic pumps up adrenalin output, blood pressure, chest pain incidence, reports of depression, anger and people hating their jobs. The death rate gets better but our lives get worse.

The Honda blonde makes her move, a bit of tactics that involves her looking to see if the Cherokee sailor sees her, but acting at the same time as if she doesn't see him as she slashes in front of him. The sailor hits the brakes. Your gut tightens. You remember the truck behind you, and imagine him hitting an air horn so loud that it lifts the paint right off your trunk. You decide not to hit your brakes. You look ahead and see the Cherokee sailor lifting both hands and stretching his neck past the steering wheel to scream at Honda blonde, rugged individualism degenerating to bugged individualism ...

" ... moving well ... "

Indeed. But you know it probably won't last. You'd be happy to stay at 30 miles an hour, but you're at the cusp of the Q/K curve, and things are about to get worse. Strangely enough, surveys show that commuter satisfaction gets radically worse too below 30 miles an hour, as if the laws of traffic psychology and traffic physics were synchronized.

You come around the bend by the Mormon Temple. You swear. Brake lights ripple in front of you. Behind you, the truck hits his brakes, that terrible dry sigh that reminds you of the air the dentist blows on your freshly drilled tooth.

You are down to 15 miles an hour. If you could escape, you would. But it's too late. Researchers at Systems Technology Inc. in California have noticed that people won't get off a highway until traffic slows to 10 or 15 miles an hour, well around the tip of the Q/K curve.

Honda strokes her hair, the sailor lays a forefinger on his upper lip, as if they're awaking from the grimy trance of freeway driving and touching themselves to make sure this is real, this crawling past the golden spires of the Mormon Temple in the mucilage-colored haze.

Your coffee cup is empty but you roll one last cool drop into your mouth just for something to do. One cup used to get you all the way to work.

The sailor picks up his car phone. Maybe he's one of those suburban lawyers who bills hours of time every day from traffic jams. Or he's calling a radio station to request a record. You hear about car faxes too, and out in California they're supposed to have car microwaves and car refrigerators.

Weird, you think: People buy their cars as if they're houses now -- for the sound system, the security, the air conditioning. And people buy houses as if they're cars, transportation devices. "Found one 20 minutes from the Beltway," they say. "It puts my husband 15 minutes closer to his new office and the kids don't have to take the bus to school."

Weird, but only because you're used to an idea of suburbs as places where the home is a sanctuary, safe from the greedy city, getting and spending. Now, as Robert Fishman writes in "Bourgeois Utopias," that idea is dying. Goodbye, Ozzie and Harriet. "The single family detached house on the periphery is preferred as a convenient base from which both spouses can rapidly reach their jobs."

Or slowly reach them.

Stuck. Crawling along the Beltway. E pluribus unum. Out of many Americans, one big American traffic jam.

You'd like to think that at least it's democracy, you're all the same when the Q/K curve takes over, but the Cherokee sailor looks like a boss of some kind, which means he doesn't have to be at his office on time the way you do, the way his secretary does. Bosses can ignore the unpredictability of the curve. Munchkins can't. They have to leave earlier every morning, even if they live the same distance from work. Except that they don't live the same distance. More and more, they live farther.

Back before all these highways got built, a lot of poor people lived next to the factories, and a lot of rich ones lived out in Daisyland. Now, the pattern is reversing, especially with the jobs moving out to the pricey suburbs -- Mobil Corp. to Fairfax, Marriott Corp. to I-270 in Montgomery County. A rule of thumb among commercial real estate agents states that when a company relocates to the suburbs, it relocates as close it can to the house of the chief executive officer without lowering his real estate values.

Back before the highways, your father and his friends were apt to ride the same railroad to work. Now, there's twice as much commuting between suburbs as there is from suburbs to central cities, which is one reason that a smaller and smaller share of Americans rides mass transit. It's hard to plan transit to serve a family in which the wife commutes from Springfield, Va., to Germantown, Md., the husband goes to Tysons Corner, and one of the kids works construction, although the city-planning types who smirk at suburbs still invoke "the need for mass transit" as if they're invoking a truth beyond questioning. Planners love mass transit the way plannees love the automobile. It gives them power.

On the other hand, when you look down the length of this traffic jam, it's as tidy as strings of railroad cars crawling into Union Station. Maybe we've created a new kind of train, except that you have to buy your part of it, and fuel it and maintain it. And you have nobody to blame when it doesn't run on time. If a dictator took over America, could he ask for more? We can organize to demand better education or health care, but we've yet to figure out a way to petition for redress of traffic jams -- they are beyond democracy, so far.

You stare out at all these drivers grinding past the Mormon Temple, no escape. They look about as free as North Koreans trudging out to the Pyongyang potash works in their padded suits every morning.

Up ahead, cars start to pull away. You're rolling. You glance at the shoulder to see if there was an accident, but you've learned better. It's the Q/K curve again, the laws of physics playing a dirty trick on you. No reason for it at all. Like lower back pain. Like being vandalized.

When, you wonder, did people start looking a little ridiculous behind the wheels of cars, like men in barber chairs or women waiting in front of restaurants, trapped and exposed, "a strange and exhilarating mixture of long-range confidence and close-range wariness," as an Englishman named Reyner Banham wrote of the Los Angeles freeways, and this was back in the early '70s, when they were still working well. "Yet what seems to be hardly noticed ... is the almost total surrender of personal freedom for most of the journey." The laws, cops, fences, concrete Jersey barriers, the cars themselves, helicopter surveillance, TV cameras, limited access, the Q/K curve ...

'Like That Thing in Vietnam'

Ah, freedom. George Bernard Shaw once asked: "What Englishman would give his mind to politics as long as he can afford to keep a motorcar?"

We have 4,000 books about what happens to the psyche of America when Americans spend X hours a day watching television -- we become a nation of illiterate, ultra-violent, brain-dead couch potatoes etc. etc. -- but where is the book that tells us what happens to the psyche of America when Americans spend X hours a day stuck in traffic, combining the worst of totalitarian control and frontier anarchy, mass transit and the automobile, public and private life?

It's probably not fair to expect traffic engineers to care any more about the personal reactions of individual Americans than architects, city planners, politicians, sociologists, journalists, economists or any of the other builders of modern America do.

At the Council of Governments, Ron Kirby, director of transportation planning, says: "Planners deal in aggregates -- they're not much interested in individuals. We don't take it the next step and ask what effect this is having on choices or family life."

At the Program on Advanced Technology for the Highway in California, technical director Steven Shladover says: "In general in this country, there's not much interest in human factors. I don't really know why."

At the Federal Highway Administration's research department, Lawrence Powers says: "There's an additional cost being paid above fuel and time. There's health -- frustration, aggravation, a high arousal state."

Alan Pisarski, author of "Commuting in America," says: "These guys get so hooked on making their freeways work, they don't deal with getting people where they want to go. What about the people who are stopped from traveling, what are the social and economic questions? If people stay home, the engineers don't care, and some people see it as a solution, but you're shutting down the system."

But then, the Q/K curve is already doing that.

Pisarski says: "It's like that thing in Vietnam where the guy said, 'We had to destroy the village in order to save it.' "

Some things the planners and economists understand very well.

Along with the Q/K curve they understand the concept of excess capacity.

At the Institute of Transportation Engineers, Tom Brahms says: "In the 1950s, we found the solution in capacity increase. Now we find it in excess capacity."

Back then, we built more highways, in other words. Now we're trying to find new ways to get more out of them.

We turn shoulders into lanes, we shrink lanes from 12 feet to 11 feet, we make streets one way at rush hour so we can drive on the whole road instead of just half of it. Then we notice excess capacity inside cars as well -- the average car carries only 1.2 people, and a few minutes on the calculator demonstrate that if we could only get that up to 1.7 people, there would be no more Q/K-curve traffic jam problem in America. Hence car pools, van pools and the High Occupancy Vehicle lanes on I-395 or the diamond lanes on the Los Angeles freeways. (The limits to HOV lanes are mathematical as well: It's hard to find people going to the same place, and next to impossible when the road runs from one suburb to another.)

Then we notice all the empty houses during the workday, and in California, at least, we encourage people to "telecommute" -- work at home on computer terminals.

Another project in California proposes equipping cars with radar and automating the highways so that cars would move along at 60 miles an hour, three feet apart, thus using up excess capacity between cars.

But wouldn't people panic at not being in control?

That's not the problem, says Shladover. "The weakest point is the litigiousness of American society, the lawsuits you'd have when things went wrong. We've got people looking at how to change the law."

How to use up the excess capacity in our legal system, in other words.

We also look for excess capacity in peoples' minds. We lower frustration with signs warning of delays, construction and detours. When that's not enough, one Beltway sign now advises drivers to be prepared for "sudden aggravation."

With the system called "ramp metering," engineers know just how much excess capacity of patience people have with stoplights placed at the foot of entrance ramps: 12 seconds. The stoplights are there to keep traffic from hitting the tip of the Q/K curve, but if you hold drivers longer than 12 seconds, they go through the lights, so lemming-desperate are they to get into the jam. Here, the limits are political. Drivers backed up behind a ramp-meter stoplight see long-distance drivers sailing along while they have to wait to get onto the highway to make a three-mile drive. They get angry. They complain.

Drivers find excess capacity in other drivers' goodwill and manners. They exploit it by weaving in and out, cutting into ramp lines, tailgating, driving on shoulders, cheating on the HOV lanes and making illegal U-turns.

With car phones they use up excess capacity in their own cars. With books on tape, they find it in their own minds. With the car ads on TV, they can fantasize about what driving was like when it used to be fun -- the ads are art for the age of the traffic jam, perhaps, like those races on television where the Big Wheel high-rise pickups mount other cars and crush them.

And when there's no place left to go and nothing left to do, we hit Q/K curves of the psyche. As we've learned in the century since the closing of the frontier in America, this is a country that gets depressed and frustrated when there's no more excess capacity.

At the University of California at Irvine, psychologist Raymond Novaco has concluded that "traffic congestion increases blood pressure, affects mood and lowers frustration tolerance." He says people who commute in bad traffic are more apt to take sick days off, and to change jobs. They become "tense, irritable, tired, sad, burdened and intolerant." They get chest pains. He warns of "reduced levels of employee productivity and morale."

And it's not the quantity of time spent on the road as much as it may be the quality that counts. In a paper written with Daniel Stokols he says that "the duration of the journey may be a less crucial determinant of commuter stress than certain other conditions of travel, including the crowdedness and complexity of commuting situations."

A long, smooth commute provokes less stress than a short, nasty one, in other words. (Despite newspaper stories about wildly long commutes, less than 4 percent of all work trips are more than 30 miles, according to the Transportation Research Board.)

The key, Novaco says, is freedom of choice.

If drivers believe they have been free to choose the jobs and homes that bring on traffic misery, they don't suffer as much as the ones who feel forced into it.

This idea leads to Novaco's most startling finding, that Type A personalities, the aggressive and competitive types, suffer less in bad traffic than Type B personalities. "Type A personalities had lower stress responses under high impedance than did the more relaxed and easygoing Type B's." Novaco thinks the reason is that Type A's work harder to control the choices over their lives, and get more satisfaction out of their homes and jobs.

Will terrible traffic drive out the Type B's, leaving the roads to ever more competitive and stress-loving Type A's gobbling up the excess capacity all the way around the Q/K curve? With their books on tape and car phones will they be willing to sit in traffic jams with no limit but the size of the human bladder, and their own propensity for panic?

An Atlanta psychologist now treats traffic phobia in a course aimed at making you able to drive through "Spaghetti Junction" northeast of town, where an eight-lane highway meets a 12-lane highway.

Ask engineers what hope there is, and they'll point out that we may not have a car available to every licensed driver, yet. Things may get worse, but then they may stop getting worse, unless our road system collapses or we get another social revolution akin to the tens of millions of women commuters entering the work force in the '70s. Maybe the Type A people will drive everyone else off the highways and then proceed to kill each other when they aren't dying of heart attacks.

There is little sign that things are getting better. What you can do is try to control the ways in which they get worse. Or leave. Head for Alaska, say. Except you may be disheartened to see posters reading "Buddy Up, Alaska," with a phone number -- 907-562-POOL -- for people trying to beat the traffic jams in Anchorage.

The Q/K curve is everywhere.

" ... no visible reason ... "