A person's reaction to a terrible accident is usually to stop. But fear of consequences can lead some to drive away.
A Catholic bishop from Arizona runs over a jaywalking pedestrian and drives off.
A drunk Texas woman hits a homeless man, then leaves him embedded in her windshield for two days before dumping him in a park to die.
And in Tampa, an elementary school teacher involved in a crash that killed two brothers waits five days to come forward.
Since that March 31 accident, Tampa Bay area residents have struggled to understand how any driver could leave the scene of a crash in which four children were hit. Experts say most people who flee have something to hide or protect. Others haven't developed a strong conscience, or they've killed it.
"All of us have the capacity to do the wrong thing, and at times we do," said Katie Sutliff, a character development consultant for the nonprofit Ethics Resource Center in Washington.
"I think doing the right thing vs. making the wrong choice is a composite of who we are. . . . I think we tend to think of who are good people and who are bad people by extraordinary moments. But extraordinary moments are the result of hundreds of thousands of ordinary moments of who we are."
To be sure, accidents can bring out the best in people - the passer-by who rescues someone from a burning car - or showcase the worst.
Many people have the urge to leave when they come upon a horrible accident, whether they've caused it or are bystanders, experts say, but the vast majority stop when they are in an accident.
Hit-and-run accidents have been on the decline nationally and in Florida even as the population has boomed and fatal accidents have increased. In 2002, 3.4 percent of all accidents in Florida were hit-and-runs compared with 4.4 percent in 1982.
But when driver Jennifer Porter, 28, a dance teacher from a middle-class family, left the fatal accident she was involved in, the questions mounted.
"What was she thinking?"
"Why didn't she come forward immediately?"
The accident in north Tampa, in which one or more cars plowed into four children crossing 22nd Street near 142nd Avenue, killed Bryant Wilkins, 13, and his 3-year-old brother, Durontae Caldwell, and injured their 8-year-old sister and 2-year-old brother.
Sutliff said hit-and-run accidents make her think of a famous quote by English historian and statesman Baron Thomas Babington Macauley, who lived in the 19th century and once said:
"The measure of a man's character is what he would do if he knew he never would be found out."
The media dubbed him the hit-and-run bishop. Arizona Bishop Thomas O'Brien, who hit a jaywalking pedestrian last June and drove off, said he thought he hit a dog.
Jurors in his February trial didn't believe him. They convicted him of hit-and-run, and he was sentenced to 1,000 hours of community service and banned from driving for five years.
The accident ended his career as head of the diocese and occurred as his diocese was in the midst of a sex abuse investigation. His case may illustrate the hallmarks of a classic hit-and-run.
Traffic psychologist Leon James, a professor at the University of Hawaii, notes that people who have something to hide or protect are most likely to flee an accident.
They may be trying to preserve a job promotion. A public image. A political campaign. Maybe they're trying to hide who was in the car with them or that they had been drinking.
"That's the strongest factor: "I have something to hide and I don't want to face police,' " James said. "We're scared that everything in our life is going to fall down around us if this gets to be known. It's the wrong thinking, and it's also illegal."
A Texas woman under the influence of alcohol and drugs hit a homeless man who became embedded in her windshield. She said she didn't know what to do.
Chante Mallard, 27, did nothing for two days. Then she dumped the man in a nearby park. He died of blood loss, and she received 50 years in prison.
James said many people panic because they aren't prepared for the sudden shock of an accident. Their faces become flushed. Their muscles tighten. They breathe heavily. They tremble and, finally, their vision becomes blurry.
"It's uncontrolled, mounting fear," James said. "And why some people stop and say, "How do I make this right, how do I make up for what I did?' and other people try to get away, it's about conscience."
James says everyone has a conscience in the beginning, but not everyone retains it.
Factors contributing to the development of a strong conscience include education and the way parents discipline their children. Both strengthen a person's rational thinking, key to making good decisions.
For example, James said, parents who always use the "because I said so" line are not giving their children an opportunity to develop their rational thinking. Similarly, parents who are inconsistent in their rules or who make too many exceptions bring up children who have weaker consciences, he said.
The traffic psychologist recommends people think about what they would do in a high-stress accident so they are prepared. Those who have thought about it or formulated a plan typically handle the situation best.
Barry Cohen, Jennifer Porter's attorney, said his client was "frightened beyond imagination."
But police say it is rare for someone to flee an accident simply because they are afraid. Typically, they are drunk, wanted for another crime or lack insurance. (There has been no indication in the Tampa case that any of those factors are involved.)
"People may be fearful, but it's for one of the underlying reasons, but just scared within itself? No," said Tampa police Sgt. David Puig, who is in charge of the auto theft and hit-and-run squad. "A lot of people are involved in traffic accidents and more people stop than don't."
Typically, 18 percent of all pedestrian fatalities involve a driver who flees the accident, according to the National Highway Traffic Safety Administration.
About a half-dozen drivers charged with hit-and-run fatalities over the years in the Tampa Bay area declined to talk to the Times for this story.
Several said they didn't realize they had hit a person. Police say that is a common response from hit-and-run drivers who are later caught.
There are degrees of altruism in humans, said Peter Rothe, a traffic sociologist from the University of Alberta in Canada. Some people are always on the lookout for opportunities to help their fellow human beings, while others are always in self-protection mode.
Robert Franke was traveling with his 9-year-old daughter in St. Petersburg in 1997 when he hit a drunk man lying in the road and sped away. Franke, then 36, was drunk. He enlisted his daughter to help clean blood off the car and lie about it. He went to jail for six months because of his actions.
On the other end of the spectrum is Horace Martin, who was driving with his 12-year-old daughter in Clearwater last year when he saw a plane crash, leaped onto the burning wing with a garbage can of water and doused a screaming man before pulling him to safety.
Martin said he felt no fear when he ran for the burning plane last August. "I think it's more adrenaline than anything," said Martin, 44. "I grabbed those garbage cans and filled them with water from a retention pond. I don't know how I lifted them. It still p----- me off, these guys bigger than me standing there."
Martin said it was not his first rescue. A decade ago, he was on the east coast of Florida when he came across a burning car that had flipped. He kicked out the glass in the back window and rescued a 2-year-old with broken arms and legs.
Martin said he was raised to treat others as he would want to be treated. It is his overriding philosophy.
- Times researcher Caryn Baird contributed to this report, which used information from Times wires.