Like many big cities in America, Atlanta is surrounded by a circular highway that connects with various freeway arteries that go through the downtown area. Weekday mornings and early evenings, no matter which highway you're on, or what direction you're going, you'll likely end up stuck in some hot traffic hell.
Dana Jones, 26, used to drive from the south end of the city by the airport to a northern suburb at peak commuting times, right through the daily mess.
"There were so many people out," Jones says. "You get road rage because nobody will let you in; nobody will merge right. It's just aggravating."
Despite the perils of a long commute, most people in the United States drive to work, according to the American Community Survey. In fact, more than 75 percent of Americans make the trek to work alone.
The stress of waiting in gridlock can get intense if you're in a hurry, leaving you feeling frustrated and anxious about the traffic. That stress can translate into deeper health hazards. Try to distract yourself with your smartphone, and you can put yourself and other drivers in even more danger.
Road rage: An 'emotional spin cycle'
LeeAnne Minnick was sitting in gridlocked traffic, waiting to get on an on-ramp, in a line of cars that had pulled over to let an ambulance pass. Suddenly, another driver darted out behind Minnick to tail the ambulance, taking advantage of the cars that had been moved, to enter the freeway.
"That incensed me," says Minnick, who makes a lengthy commute from Athens, Ga., to Atlanta -- about a 70-mile trip -- three days a week. "I immediately flew into a rage over it."
That happened a couple months ago, and Minnick still sounds irritated when she describes it. She doesn't act aggressively toward other drivers, but she does get bothered by disrespectful behavior on the road.
It's easy to get lost in a cycle of emotions where you're talking to yourself and ruminating about traffic situations, says Leon James, professor of psychology at the University of Hawaii and co-author of "Road Rage and Aggressive Driving."
"Impatience, if you don't handle it at the beginning, tends to turn into resentment and anger," James says.
The back seat of the car is what James calls the "road rage nursery." It's where kids hear their parents cursing out other drivers and expressing their disbelief about everyone else's poor skills on the road. Children learn the culture of aggressive driving in this way, he says.
"We use it as an opportunity to disrespect everything and say bad words that we would be shocked to say in any other place."
Another problem is that after a bad commute, people tend not to let it go, James says. They walk into the office and complain about their experiences, which leads to entire conversations about bad traffic and bad drivers. This venting may feel good in the moment, but it reinforces the emotions for the next driving trip, he says.
James' solution: Monitor your traffic emotions. You might try keeping a diary of how you feel every day after your commute, or just keep a mental note about your state of mind. What are your negative thoughts while on the road? Are they justified?
Confronting your internal dialogue about commuting frustrations may help. You may realize that your negative thoughts may not be proportional to the offenses you perceive from other drivers.
James recommends asking yourself: "Am I the kind of person who thinks these things about people?" and "Is this the kind of person I want to be?"
Stress: When driving kills slowly
Traffic situations may trigger in us primal instincts that evolved in humans to promote survival, so that we can protect ourselves against threats, experts say.
The "aggressive, combative, competitive frame for driving" may be linked to our evolutionary past, but it could have implications for cardiovascular disease, says David Strayer, a psychology professor at the University of Utah.
In one experiment, Strayer and colleagues ran a simulation where people drove under the assumption that they were late to a meeting, and there was a financial incentive to get there before other people. One group drove in high-density traffic, another had an easier traffic environment. Some people were told there was a time limit.
Men more then women got into aggressive driving mode, showing an elevated blood pressure when under pressure to weave their way through heavy traffic. In general, both men and women who adopt an aggressive driving persona seem to show this, Strayer says.
"In the simulator studies we've done, they'll actually start driving by cars and flipping them off and honking at them," Strayer says. "That's just a computer, a computer rendition!"
Long-term stress increases the risk of cardiovascular disease, he says. Research on the precise level of cardiovascular risk is limited, but recent data doesn't paint a flattering picture for the vehicular commuter.
A 2012 study in the American Journal of Preventive Medicine found that the farther people commute by vehicle, the higher their blood pressure and body mass index is likely to be. Also, the farther the commute, the less physical activity the person was likely to get.