Do You Get Traffic Jitters? (Dec, 1940)

I love that picture.

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Do You Get Traffic Jitters?

IMAGINE that you are driving your car at a good clip down a boulevard running through the residential section of a city. The road is wide and uncluttered by traffic. Your car purrs along smoothly. Suddenly, with no warning whatever, a woman darts out from the sidewalk and throws herself directly into your path.

What will your reactions be? What will be the effect on your nerves? How will the shock of the experience affect your subsequent driving?

California scientists can answer these questions exactly. For recently they have been hurling bodies—stuffed dummies, of course, but drivers don’t realize that at the time—in front of automobiles, as one phase of an elaborate series of road tests to determine how the hazards of automobile driving affect the nerves, and consequently the driving ability, of the average motorist.

Their conclusions afford valuable hints on how all drivers can combat traffic jitters.

The tests, which utilize specially designed electrical apparatus, were developed by Dr. George Mount, a prominent psychologist, working in cooperation with the Union Oil Company of California. In designing the instruments to check the nervous reactions of drivers, Dr. Mount and his associates followed the principle that a person’s nervous tension will be clearly indicated in three main ways: by his heartbeat, by his blood pressure, and by the electrical sensitivity of his skin—for the electrical resistance of your skin changes in direct proportion to the state of your nerves.

By means of pick-up microphones attached to wrists and chest, instruments for recording heartbeat and blood pressure were easily adapted to the problem of making continuous records while a driver was actually operating a car under traffic conditions. The development of a method of recording changes in skin resistance, however, required months of research before an acceptable solution was found. Electrodes are attached to the driver’s hands. Between the electrodes and the skin, a special saline jelly is used to insure a good contact. From the electrodes wires lead to recording instruments resting on the rear seat of the car. By means of a pointer and dial, the driver’s skin resistance to low-amperage currents can be determined at any instant. Thus, this apparatus, together with the heartbeat and blood-pressure instruments, writes a running” story of the nerve responses of the driver as he meets the numerous problems of traffic in congested areas.

When hundreds of subjects had been tested on the road with this equipment, the California scientists discovered that there are two distinct types of nervous strain brought on by traffic driving: steady strain, and shock strain.

Steady strain is the general nervousness that accumulates during difficult driving, regardless of whether the motorist encounters any emergencies during the trip. In thirty minutes of traffic driving, the nervousness of the average motorist, the psychologists determined, is increased twelve percent by this steady strain.

Naturally, steady strain will be further increased by shock strain, the type that occurs when a driver just misses a jaywalker, can’t stop for a suddenly changed traffic signal, realizes that his brakes have failed, or is confronted with a similar emergency. Shock strain, it was found, will increase a driver’s nervousness by as much as twenty-seven percent in a half hour of traffic driving.

Twenty-seven percent seems a tremendous jump, but the scientists point out that one close call in traffic will speed a driver’s heart action as much as

twenty-five beats a minute. At the same time, the resistance of the skin to electrical currents makes a similar change, blood pressure skyrockets, and muscles become tense. Incidentally, it is interesting to note that women proved to be thirty percent more nervous than men after similar traffic-test drives. In general, Dr. Mount states, women are less affected by steady strain and more by shock strain than men.

FROM these traffic tests the scientists also discovered what they term a short-circuit reaction. This occurs when a driver responds automatically to a traffic problem, without any conscious thought about it. Certain of these short-circuit reactions can become dangerous. If a driver applies his brakes in any and every emergency, he will eventually form a short-circuit reaction by which he will automatically brake without conscious thought of what he is doing. Then one day an emergency will arise when applying the brakes would be the worst possible action to take—during a skid on a wet pavement, for example.

To prevent this, the scientists suggest that all drivers look out for the first indications of any type of short-circuit nerve reaction, and then combat it before it gains headway. This can be done, they state, simply by occasionally forcing yourself to think why you stop or accelerate your car in a given situation, before you actually do it.

Noise is another element that has a bearing on traffic nerves, the investigators found. By spotting sensitive microphones to record the sound volume inside of several cars, and then having subjects drive the cars while their reactions were checked, the scientists discovered that car sounds definitely affect driving ability.

But, strangely enough, the effect of car noise on a driver is to decrease the efficiency, not of his sense of hearing, but of his senses of sight and smell, and his speed of nerve reaction. This agrees with the psychological principle that when one sense is overstimulated, the other senses are dulled.


1 Don’t “fight” traffic, instead of fretting and fuming, save your nerves for more important things.

2 Don’t drive under physical strain. Make yourself as comfortable as you can with seat adjustments and cushions.

3 Don’t argue with other drivers. Bawling out the other fellow does no good and merely frazzles your own nerves.

4 Don’t tolerate “bugs” in your car. A smoothly running machine is good insurance against traffic jitters.

5 Don’t drive a noisy car. Knocks, squeaks, and rattles dull your senses and slow up your reactions in emergencies.

6 Don’t neglect to wear glasses if you need them. Eye strain adds to general nervous strain when you are driving.

7 Don’t drive so fast that you lose the feeling of complete control over your car Confidence is what keeps your nerves cairn.

  1. Caya says: May 25, 20076:19 am

    Wow, several thoughts. First, it would make me very, very “jittery” to have that load of stuff strapped to me as I drive, and those guys recording me!!! haha- Second, I am amazed that they risked everybody’s life by throwing that dummy into the road like that. And terrified the driver! Good grief! What if he had panicked, and drove into a tree?? Lastly, the haircut on the girl in the very last picture is simply hideous.

  2. docca says: May 25, 20076:48 pm

    Watch out for the crazy dummy-hurling scientists! They could be sneaking around every corner on your city!

  3. Stannous says: May 26, 20076:51 pm

    These tests being in S Cal I’d add:

    8 Don’t shoot at other drivers just because they’re rude or incredibly inept. They may be better armed and be better shots.

  4. Ed T. says: March 10, 200810:42 am

    That first picture is awesome!

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