Derailing Illusions That Kill
In the United States, trains collide with vehicles 3,000 times a year, killing more than 300 people.
On Sept. 16, Benjamin Martinez of Orange became the sixth Southern California resident killed in such a crash this year when his Acura Legend was struck by a Metrolink train traveling at 90 mph through Santa Ana. According to some witnesses, Martinez, 29, speeded up just as the arm of the train’s warning gate came down.
No one will ever know what Martinez was thinking in the seconds before the train slammed into him. But in almost every case, grade-crossing accidents such as Martinez’s are blamed on driver carelessness.
In fact, it is a lot more complicated than that.
Scientists say that many of these accidents are caused by deadly misperceptions, the visual and behavioral quirks known to science but not to ordinary drivers. And making rail-crossing encounters even more treacherous are train and crossing designs that fail to take into account how people perceive and behave.
It’s not enough to stop, look and listen at railroad crossings, these experts warn, because what you think you see can kill you.
“The attitude of the Federal Railroad Administration is that almost every accident that ever happened at a railroad crossing is the driver’s fault,” said cognitive psychologist Marc Green, a partner in the Toronto consulting firm Visual Expert.
One peculiarity of human perception is that large objects in motion appear to be moving more slowly than they really are. We can observe this phenomenon at any airport, said Herschel Liebowitz, emeritus professor of psychology at Pennsylvania State University. Jumbo jets appear to drift down to the tarmac during landings, while smaller jets seem to race toward the runway, even when the larger plane is going faster.
Liebowitz, who first described the size/speed effect and other grade-crossing perils in 1985, field-tested his theories by riding in the cab of a locomotive and questioning railroad personnel: “It was almost immediately obvious what the problem was.... People misestimated the speed of trains.”
The problem is compounded by perspective.
When we look down a railroad track, we don’t see the rails, or the telephone poles running along the tracks, as parallel. We see them converging in the distance at what artists and scientists call the vanishing point. As Liebowitz explains, we have learned to associate that apparent convergence with distance, and so we are likely to assume that the train is farther away than it really is.
Collisions also have what Liebowitz calls a “deceptive geometry” that can prove fatal.
Green explains the problem: Typically, you glimpse the train with your peripheral vision. Never as clear as central vision, peripheral vision is especially poor at gauging velocity. Even as the train moves toward you, and you move toward it, the train’s image maintains a relatively constant position on your retina, at the edge of your visual field. The result: “You don’t see it moving,” Green said, and you assume it is still a safe distance away.
Then, when you are about to collide, the train’s image on your retina suddenly expands in all directions -- a condition called looming. But at that point, you probably can’t stop in time, and neither can the train.
By Green’s estimate, perception -- or misperception -- is a factor in more than 80% of highway accidents, including those involving trains.
Many public officials charged with train-related safety are aware of the science of rail accidents but continue to take a Darwinian view of them.
“We know that the problem is there are just too many impatient drivers who fail to obey traffic regulations at either active or passive crossings,” said Warren Flatau, a spokesman for the Federal Railroad Administration.
The tendency to blame the victim in grade-crossing accidents exasperates cognitive psychologist Green: “That lets the authorities off the hook. Then they don’t have to redesign the system.”
The United States has made progress in train safety, experts say.
“Railroad crossing deaths in the U.S. have come down from 786 in 1975 to 315 in 2001. That’s a pretty good achievement, " said Eric Wigglesworth, an Australian accident researcher who won the Order of Australia -- comparable to British knighthood -- for his contributions to Australian public health and safety.
“I think this was largely due to the U.S. government’s rail-highway crossings program which since 1978 has injected $4 billion into crossings improvements,” Wigglesworth said.
The elimination of thousands of grade crossings and the increase in so-called active crossings, especially in heavily populated areas, have been important advances.
Twenty years ago, only about 50,000 of the country’s 225,000 public grade crossings were protected by flashing lights, bells and/or gates that drop down when a train is about to pass. Today, there are about 62,000 of these active crossings out of 154,000.
Such active warning systems are expensive -- even simple ones can cost $150,000 to install. And active crossings have human-factors problems of their own, which may help explain why they account for half of all grade-crossing collisions.
Liebowitz described one major problem 20 years ago. The low-tech gates then in use at active crossings dropped at a fixed time, whether the passing train was traveling quickly or slowly. As a result, drivers often had to wait long after the gates had dropped for a train to arrive.
But drivers are impatient, and those who have had to wait time after time for the train may decide that they can safely ignore the warnings.
“It’s called ‘the cry wolf phenomenon,’ ” Green said.
Research published in the early 1990s convinced the Federal Railroad Administration that some motorists who had to wait more than 40 to 50 seconds at an active crossing would try to drive around the gates. Now, most active crossings are equipped with electronic “predictors” that gauge an approaching train’s speed and lower the gates as little as 20 seconds before the train arrives.
Still, unless rail safety experts determine what makes some grade crossings so dangerous, the Southland’s rail lines could become “killing fields,” said Najmedin Meshkati, a professor of industrial and systems engineering at USC.
Meshkati is especially fearful about what will happen on the Metropolitan Transportation Authority’s new 13.7-mile Gold Line between Los Angeles and Pasadena, and the planned Exposition light rail in downtown Los Angeles. Both lines are designed to serve busy, multicultural and multigenerational neighborhoods.
Meshkati’s fears are understandable. Until the Gold Line opened July 26, MTA’s Blue Line was the only one of its three routes to have grade crossings. The tracks of the others are elevated, underground or run along the median of freeways, a safe, but costly-to-achieve condition called grade separation. Since opening in 1990, the 22-mile Blue Line has accounted for 62 of the MTA’s 65 fatalities.
Educating the public is one way to prevent accidents.
Operation Lifesaver, which coordinates rail safety messages throughout the United States, includes the larger-looks-slower phenomenon and the perspective illusion in its literature and also reminds drivers and those tempted to take their chances on railroad tracks that trains need a long time to stop.
Local transportation agencies also work hard at public education. So far this year, Metrolink, which has 443 at-grade crossings, made safety presentations to some 35,000 people. And the MTA spoke to 50,000 schoolchildren to prepare them for the Gold Line, which had no serious accidents before the MTA mechanics strike shut it down. (The strike was resolved Monday and service has resumed.)
But grade crossings claimed another victim Nov. 6 when Dana Santos, 46, of Oxnard was struck by a Metrolink train as she waited in her SUV between Oxnard and Camarillo. Santos apparently did not try to beat the train, but was caught on the tracks when the crossing arms came down. She died two days later.
Critics point out that most safety programs fail, in part, because most drivers who try to beat a train across the tracks believe they are safe. It is only recently, according to Meshkati and others, that the rail industry has begun looking at driver behavior as it is, rather than as it should be. Meshkati’s own work focuses on how decision-making styles and crossing complexity may contribute to collisions.
Among the rarely recognized dangers: the difficulty of hearing warning bells when sitting in a modern soundproofed car and the likelihood that new immigrants won’t recognize the traditional American crossbuck, the simple X-shaped railroad sign that warns drivers to yield to an oncoming train. And decision-making at grade crossings is even tougher at night.
“The demands that are placed on the driver at a railroad crossing are extraordinary,” said c Wigglesworth, the Australian researcher who successfully campaigned for improved warning systems there. “It’s not surprising there are so many accidents.”
Ten years ago, Wigglesworth persuaded Australian lawmakers to address the danger of putting the same warning signs at both passive and active crossings. “The mix of active and passive systems kills people,” he said, and explained why: Say you are a driver approaching an active crossing, marked with a crossbuck, warning bells, lights and gates. If the lights don’t flash and the gates are up, you know it is safe to cross the tracks.
Then you come to a passive crossing. It too is marked with a crossbuck. But, this time, the lack of red lights and lowered gates doesn’t mean “Go ahead.” It means just the opposite. The crossbuck tells you to stop and look because a train may indeed be racing your way.
Using the same traffic signs when different actions are desired breaks one of the Ten Commandments of human-factors engineering, Wigglesworth explains: “If you use the same stimulus, you must expect the same response.”
Australia’s 3,400 active crossings continue to be marked by a crossbuck and other warning devices. But its 6,000 passive crossings now have two unique signs of their own, thanks to Wigglesworth. The first sign shows the silhouette of a train puffing smoke. The second sign is a diagram that shows the angle at which the tracks cross the road. This directional sign tells the driver exactly where to look for the train, an enormous help in making a complex, life-or-death decision quickly.
Like many other experts, Wigglesworth believes systems are easier to change than people’s behavior. He would like to see greater use of such potential lifesavers as signals inside cars that warn of an imminent collision with a train (now under study by the Federal Railroad Administration).
The agency is examining why drivers behave dangerously at grade crossings, an important first step. And it is studying so-called “intelligent transportation systems” that would warn train personnel, even stop the train, when a vehicle or person is on the tracks.
For now, gates that effectively keep cars from driving across the tracks are a good interim solution. But until grade crossings are eliminated or futuristic systems are in place, human-factors experts say crossings could be made safer with:
* Better signs and warning devices. Drivers should be warned early and often that they’re approaching tracks. Also, people understand active, affirmative statements (“Stop for train”) more readily than negative ones (“Don’t block tracks”).
Signs also should address specific dangers. Many Blue Line collisions resulted from drivers making illegal left turns, apparently unaware that a train was approaching from behind. An overhead fiber-optic sign that shows a picture of a train labeled “train” (better than the innocuous “trolley”) has cut left-turn incidents in half.
* More education. Department of Motor Vehicles materials, billboards, public-service spots and other avenues could be used more effectively to warn of optical illusions and other crossing dangers.
* Increased law enforcement. Drivers who think they can race around crossing gates may not do so if threatened with a ticket. Signs warning of $321 fines for those who cross illegally seem to encourage compliance, as does a highly visible police presence.
People tend to behave in predictable ways, and grade crossings will continue to claim lives until their designers recognize that.
Green puts it this way, repeating the mantra he learned as a graduate student, doing experiments with lab animals: “The rat is always right.”
Green explained: “If you set up an experiment and the rat doesn’t do what you want it to do, it’s not because the rat is stupid, but because you set up the experiment wrong. It’s the same with humans.... I think if we took that into consideration, we might design grade crossings differently.”