Maybe we humans come hard-wired for aggression. Recently, scientists have isolated a single gene in mice that directs the circuitry for serotonin, a brain chemical controlling aggression and other basic survival behavior. Genetically altered mice—those without the serotonin gene—hunker down in a corner of the cage and immediately attack all intruders. “It’s like road rage,” described one researcher.

Humans, say scientists, have serotonin systems very similar to mice. Look around on your daily commute, and you’ll always spot a few drivers behaving as though they’re missing a gene. They weave in and out of traffic, climb the other guy’s back bumper and cut off other cars. It’s not exactly “road rage,” which traffic safety experts define as violence that would land the perpetrator behind bars. It is, however, “aggressive driving”—hostile behavior that involves speeding, running red lights, tailgating and other ticket-worthy infractions.

Of course, only other people act like animals on the road. You would never drive aggressively. Or would you? Answer the questions below and see what brings out the beast in you.

1. Running late for work, you come upon a work zone. Signs announce,  “Left Lane Closed Ahead, Merge Right.” Traffic has already begun to back up. You fume. You’ll never get to the office in time! You zip along in the left lane until the last possible instant and try to merge at the head of the line:

a. Always.

b. Sometimes.

c. Never.

If you answered a or b—honestly, now—then you show signs of a typical Type A personality. “Type A’s are schedule-driven personalities,” explains Barbara Ward of the Club’s Traffic Safety Services department. “They don’t want to be late. They direct their anger at anything that holds them back or wastes their time.” They often speed or take other risks to save precious minutes. How can you suppress your Type A tendencies? Obviously, build more travel time into your schedule. Call ahead on a (hands-free) cell phone to say you’re stuck in traffic.

2. Driving in the far-left lane of a three-lane expressway, you’ve set your cruise control at 55. Faster traffic passes you on the right. Maybe some cars behind flash their lights, encouraging you to move over. But you won’t budge. “The speed limit is 55,” you think. “I obey it. Others should, too. I’m doing everyone else on the road a favor!”  You do this:

a. Always.

b. Sometimes.

c. Never.

“We call these drivers polite enforcers,” says Ward. “They think they’re the best drivers on the road, and they’re out to teach other drivers a lesson.” In extreme cases, she says, enforcers become outraged at a perceived injustice committed by another driver (going out of turn at a four-way stop, for instance) and pursue the violator.

Self-righteousness can lead to violence.  If you’re concerned that other drivers are breaking the law or posing a hazard to others, report them to law enforcement. Don’t play police officer yourself.

3. This afternoon, your boss gave you a poor performance appraisal. You won’t be getting the raise you expected. Still seething, you stop at the supermarket on your way home. But before you can park, another car zips into the spot you had your eye on. You give him the horn:

a. Always.

b. Sometimes.

c. Never.

If you would sometimes or always vent your rage at another driver, you have a tendency to “kick the cat.” Cat-kickers carry unresolved anger from other parts of lives and take it out on others. Instead of venting at anonymous drivers who have nothing to do with what’s really bothering you, try to empathize. Listen to music or practice other techniques to calm yourself.

4. A big Ford Expedition pulls in front of you on a two-lane road. You can’t see around it. “Damn SUVs!” you say to yourself. “They’re everywhere! They hog the road, waste gas, and stink up the air.” You mash down on the gas and pass the Ford fast:

a. Always.

b. Sometimes.

c. Never.

“We call this personality type the Jekyll-and-Hyde,” says Ward. “Outside the car, they may be shy, soft spoken and not at all aggressive. Then, they get in their cars and become monsters.” Often, a particular type of vehicle will awaken the monster within—perhaps trucks, SUVs, BMWs or even bicycles. For some reason, they bear a grudge against the vehicle type, even when it poses no risk.

If you answered even “sometimes,” you may have a latent Mr. Hyde inside. Rather than looking for enemies, try test-driving the very vehicle you hate just to see its appeal to others. Or get over it—you didn’t ask permission when you chose your car.

5. Crawling along in rush-hour traffic on a multi-lane expressway, you notice that the next lane seems to be moving slightly faster than yours. The very idea that those people are getting ahead irks you, so you move over. But, after a while in the “faster” lane, you realize that your former lane seems to have sped up. Angrier than ever, you try to squeeze back in:

a. Always.

b. Sometimes.

c. Never.

You answered a or b? You might be a competitor—“someone who sees driving as a sport,” says Ward. “Competitors direct their anger to anyone or anything perceived as a challenge to their ego.” You see faster-moving lanes or another driver inching into the intersection ahead of you at a stoplight as a personal affront. You want to be the leader of the pack.

To quell your competitive instinct, depersonalize your driving. Where Jekyll-and-Hydes and cat-kickers need to empathize with other drivers, you shouldn’t even look at them. Rather than focusing on the outcome beyond the car, make the environment inside the car more enjoyable by listening to a book on tape or a good CD.

Driving Under the Influence

Of course, these aren’t the only situations in which stress or anger might manifest itself as aggressive driving. In fact, all of these questions boil down to a few basics: Are you in control of your emotions and your car? Or do your emotions control your vehicle through you? If the latter, then you’re doing what some experts call “driving under the influence”—not of alcohol, but of anger and stress.

Have family members or other passengers commented about the way you drive? Perhaps you find yourself using your horn nearly every time you get on the road. Or you often drive over the speed limit, weave in and out of lanes impatiently or tailgate. You might find yourself regularly cursing, yelling or making obscene gestures at other drivers. Then it’s time to seek help from a counselor, pastor, rabbi or other professional.

“Any one of these symptoms isn’t more or less important than any other,” says AAA’s Ward. “And you don’t have to have them all. Just one symptom showing up consistently indicates that you probably need assistance in controlling your anger and reducing stress.”

Ignoring the symptoms may make matters worse. Aggressive driving can escalate into road rage and outright violence. One day, while tailgating, you become enraged when the driver ahead taps his brakes. Instead of tailgating, you actually bump into him to nudge him along. “Then you’ve crossed the line,” says Ward. The time has come to get your emotions under control.

Unwinding the Right Way

A professional will suggest breathing techniques, yoga, meditation, cognitive exercises or other practical, everyday stress-reduction tactics. In addition, traffic safety experts suggest the following tips that specifically affect your driving:

• Get plenty of rest.
• Leave early, allowing enough time to account for possible delays en route.
• Keep your car well maintained. “Worrying about a breakdown because of a problem that you intended to fix but never got around to only adds to the stress behind the wheel,” says Ward.
• When possible, plan an alternate route. When construction or collisions force delays, resort to plan B.

Above all, a reminder: Unless you are a professional driver, driving is not an end in itself. Ease up—you’ll get there.

Editor’s note: The Club offers workshops on anger management and stress reduction to schools, businesses and community groups. Call 516/873-2378 for more information.

How to Keep the Peace

Even if you honestly answered “Never” to every question on the accompanying quiz, you still need to worry about aggressive driving—not as a perpetrator, but as a potential victim. How can you protect yourself from others’ aggression on the road? Experts offer the following advice:

Avoid eye contact. Animal lovers will tell you that snarling dogs interpret direct eye contact as a challenge and become more antagonistic. The same holds true with vicious humans. Don’t engage an aggressive driver in any way—even with a look.

Refrain from all gestures. The one-fingered salute and other rude gestures may provoke an incident. In fact, some safety experts caution against gestures of any kind—even polite, well-intentioned ones. For example, when you inadvertently cut someone off, you naturally want to apologize by casually waving, shrugging your shoulders or hitting your forehead with the heel of your hand in a “what-was-I-thinking?” way. “You might mean ‘I’m sorry,’ but you don’t know how another person will interpret it,” notes AAA’s Barbara Ward. “Just let it go.”

Stay in your car. When you step out of your car, an enraged driver may think you are stepping into the ring—and join you.

Seek help when you feel threatened. If you think you’re being followed by someone who intends to harm or confront you, drive immediately to a police station, hospital or anywhere where you’ll find safety in numbers. “That’s usually enough to make the aggressive driver go away,” says Ward. “If not, call the police on your cell phone or blow your horn to attract attention. Except as a last resort, don’t go home.” Driving home may represent safety, but it also leaves you vulnerable to continued harassment.

Follow the rules of the road. Little things mean a lot. Forgetting to use your blinker, stopping in the middle of the road for a chitchat or double parking even for a minute just might trigger a driver already on the edge. It’s more than a matter of courtesy or legality. It’s really a matter of self-defense.