Stage 2 Course Content 6 — Human Ability and Driving

1. Recognition, Judgment, and Operation

1. Recognition, Judgment, and Operation

When a driver applies brakes while traveling, first he/she recognizes an obstacle by seeing or hearing, judges that he/she needs to apply brakes, and then operates the brakes. This process of recognition → judgement → operation takes a little time.

Perceiving every relevant information (obstacles, etc.) in a short time is difficult. Also, when you judge the traveling speed of the vehicle, distance to an obstacle, etc., note that your judgment may not match the actual speed or distance. Further, when the surrounding condition or condition of the driver is not good, making a proper judgment becomes much more difficult. Therefore, it is important to drive knowing that there is a limit to human abilities.

Recognition (Looking, Hearing) → Judgment (Deciding) → Operation (Acting)

2. Reaction Time

The time required for a driver to recognize a dangerous situation and apply the brakes as well as for the brakes to start working is said to be about 1 second. This duration is called reaction time. As the speed increases, the distance traveled by a vehicle in 1 second becomes longer and it becomes more difficult to avoid an obstacle. Therefore, try to drive slow enough and apply brakes early enough all the time.

Distances traveled in 1 second (approximately)

Speed Distance
100 km/h 28 m
80 km/h 22 m
60 km/h 17 m
40 km/h 11 m
20 km/h 6 m

Three stages of reaction time

Reaction time = Reflection time + Time required to change pedals + Depression time

3. The Function of Vision

When driving a vehicle, you must use various functions of your body. Because we highly rely on information coming through our eyes, vision is the most critical function.

1. Vision

(1) Vision

Usually, vision is measured using the international visual acuity test chart. In such a way, the vision is measured by staring at one spot. Peripheral vision is weaker than the measured vision. Therefore, you should keep shifting your eyes as necessary instead of staring at one spot while driving, in order to pay equal attention to the surroundings. Especially, while traveling at high speed, you need to properly perceive information on the road far ahead. Always try to get information early.

(2) Dynamic visual acuity

(You move, and the other party also moves / You move, and the other party stops / You stop, and the other party moves — These cases are dynamic vision)

2. Field of Vision

(1) Field of vision

The view covered by the eyes without moving them is called field of vision. Field of vision of each eye when a person is stationary is about 160 degrees, and with both eyes, it is about 200 degrees. The extent to which colors can be judged correctly is up to around 35 degrees for each eye. People often fail to recognize the color of an object correctly when the object goes out of this extent. This means that a driver may fail to recognize a traffic signal or traffic sign correctly if he/she does not look at it carefully.

(2) The relationship between field of vision and speed

The faster the speed of a vehicle, the narrower the driver's field of vision becomes, while objects nearby become difficult to see as the driver tends to look to the distance. Therefore, be careful not to overlook pedestrians or bicycles that may dart out into the road from nearby when you are traveling at high speed.

3. Adaptation

When a person suddenly enters a bright place from a dark place, he/she cannot see things well at first because it is too bright, but after a moment his/her eyes get used to the condition and can see things as usual. This phenomenon is called brightness adaptation. On the other hand, when a person suddenly enters a dark place from a bright place, he/she cannot see things well at first, but he/she will gradually be able to see things. This phenomenon is called darkness adaptation. Darkness adaptation takes a longer time than brightness adaptation. When entering or exiting a tunnel, you must reduce speed and drive carefully.

※ During the twilight hours, it becomes dark quicker than eyes can adapt and therefore vision declines.

4. Judging Distance and Speed

Drivers should judge the distance from other vehicles or obstacles on their own during traveling. Sometimes he/she may judge the traveling speed without looking at the speedometer. However, such judgement is not always correct and may be subject to optical illusions. Therefore, drivers should make it a habit to check the speedometer instead of relying on their own judgment. Be especially careful not to exceed the speed limit when entering a general road from the expressway, as this is a common tendency. Furthermore, as road conditions change, there's a higher possibility of errors in judging the distance and speed.

(The large vehicle, the regular vehicle, and the two-wheeled vehicle appear to be lined up side by side when seen from 100 m away from them; however, actually, the large vehicle is 20 m away from the two-wheeled vehicle.)

Reference — Optical illusion

"Optical illusion" is a phenomenon that the size, length, or direction appears to differ from reality. This phenomenon is universal and can happen to anyone. It is possible that a driver makes a mistake in judging the situation due to an optical illusion and cause an accident.

(Examples)

  1. The optical illusion in which a downward slope appears to be an upward slope, and vice versa
  2. The optical illusion in which a small vehicle appears to be farther than a large vehicle
  3. The optical illusion that causes the loss of the sense of speed after getting off an expressway

2. Factors that Affect Recognition, Judgment, and Operation

There are various factors that can affect recognition, judgment, and operation, and cause undesirable effects such as prolonged reaction time. These include fatigue and the influence of alcohol, which can be prevented in advance.

1. Drinking Alcohol

1. Effects of alcohol

The effect of alcohol varies with individuals. Since alcohol can temporarily relieve tension and elevate your mood, you may feel clear-headed. However, in reality, alcohol definitely decreases brain activity. You will not be able to make a cool decision or think logically. If you drive a vehicle after drinking alcohol, you will lose your power of judgment and self-control, and therefore will not be able to perform driving operations appropriately. Also, alcohol brings various negative effects, such as declined vision, misjudgment of speed or distance, etc.

Effects of alcohol:

2. The Fearful effects of drunk driving

Drunk driving can lead to serious traffic accidents including those resulting in death. It is very dangerous to easily assume that you can drive a vehicle because some time has passed after drinking alcohol. If you have had alcohol even a little, never drive!! Also, you must not provide or offer alcohol to someone who is going to drive.

Reference — Examples of accidents often caused by drunk driving

Reference — Drunk driving and penalties

Even a little bit of alcohol definitely decreases brain activity and brings bad effects on the abilities of recognition, judgment, and operation necessary for driving. Countless serious accidents have been caused by drunk driving. Never drive after drinking alcohol. Also, you must not encourage someone who is going to drive to drink alcohol or ask someone who has drunk alcohol to drive you home. Besides a driver who drives after drinking alcohol, a person who helps a drunk person to drive or asks a drunk person to drive is subject to heavy penalty.

Prohibition against hangover driving Regardless of the situation, driving under the influence of alcohol is presumed to be drunk driving. If you drink late at night or drink too much, alcohol still remains in your body even after sleeping one night. It takes a long time to decompose alcohol in your body, even if you have drunk only one cup of alcoholic drink. Be very careful that alcohol may still remain in your body on the following day.

Penalties

(The driver) (People who are involved)
Drunk driving (Under the influence of alcohol) Imprisonment not exceeding 3 years or a fine not exceeding 500,000 yen Providing a vehicle — driver is under the influence of alcohol: Imprisonment not exceeding 3 years or a fine not exceeding 500,000 yen
Drunk driving (Intoxicated) Imprisonment not exceeding 5 years or a fine not exceeding 1,000,000 yen Providing a vehicle — driver is intoxicated: Imprisonment not exceeding 5 years or a fine not exceeding 1,000,000 yen
Violation of the duty to aid the injured (Hit and run) Imprisonment not exceeding 10 years or a fine not exceeding 1,000,000 yen Providing alcohol — driver is under the influence of alcohol: Imprisonment not exceeding 2 years or a fine not exceeding 300,000 yen
Refusal of alcohol test Imprisonment not exceeding 3 months or a fine not exceeding 500,000 yen Providing alcohol — driver is intoxicated: Imprisonment not exceeding 3 years or a fine not exceeding 500,000 yen
Requesting or asking for a ride
Knowing that the driver is intoxicated On a vehicle driven by an intoxicated driver Imprisonment not exceeding 3 years or a fine not exceeding 500,000 yen
Other than above On a vehicle driven by a driver under the influence of alcohol / On a vehicle driven by an intoxicated driver Imprisonment not exceeding 2 years or a fine not exceeding 300,000 yen

① Driving under the influence of alcohol ············· An alcohol concentration of 0.15 mg per 1 L of breath or 0.3 mg per 1 mL of blood or more remains in the body. ② Intoxicated driving ················· Driving while drunk, regardless of the alcohol amount. ③ Refusal of alcohol test ················· If it is found that a person who is inside of or about to enter a vehicle is likely to drive the vehicle, etc. under the influence of alcohol, a police officer may test that person to determine the level of alcohol. Refusal of alcohol test refers to refusing or interfering with such test.

2. Fatigue

1. Causes of fatigue

Each of the following cases can be a factor that causes a driver to feel tired.

① Irregular lifestyle due to the reasons such as lack of sleep. ② Aged or not having much driving experience. Fatigability varies with individuals. Some people get tired easily. ③ People may get tired easily due to the conditions such as time, temperature, road conditions, travel distance, and the environment inside the vehicle.

2. Effects of fatigue

Fatigue causes the symptoms such as falling asleep and yawning and changes such as reaction delays. Invisible changes may include an increase in the number of heartbeats and blood pressure. When you feel changes in your body such as drowsiness, even if it is only a little change, you have to take a rest as soon as possible.

3. Avoiding driving while exhausted

Pay attention to the following points to avoid driving while being exhausted.

① Take enough sleep and ensure physical and mental well-being before driving. Do not drive when you are sick or mentally unstable. ② Make a driving plan with plenty of time to spend in advance, and take a rest at least once every 2 hours. ③ If you feel tired, do not force yourself to drive. Park in a safe place early and take a nap or do some light exercise.

3. Other Factors

If the driver's physical or mental condition is not good, his/her reaction may delay or his/her reaction time may fluctuate. Be careful of the following conditions.

① Physical and mental conditions

When a driver is sick due to cold or other diseases, when a driver's mental condition is not good, or when a driver is in a festive mood, his/her reaction time becomes longer or fluctuates.

② Illnesses and medicines

When a person has illnesses that can cause impaired awareness at any time, such as high blood pressure, low blood pressure, and diabetes, illnesses that accompany autonomic ataxia or an abnormal sense of balance, such as dizziness, a giddy feeling when standing up, a ringing in the ears, and blurring of the eyesight, his/her reaction time may be longer. Most of the antihistamine medicines such as cold medicines, tranquilizers, etc. can be a cause of prolonged reaction time.

③ Age

In general, a person's reaction time gets longer as he/she ages. The older a person becomes, the more his/her vision, hearing, reflexes, and muscular strength decline.

④ Other

When a person is not focused on driving or when a person does not have much driving experience, his/her reaction may delay.

Let's Try — Course Content 6 — Check your understanding with right/wrong questions.

(See page 275 for answers.)

  1. Among the human senses, vision is the most important sense for safe driving.
  2. While driving, it is better to look blankly at the whole scene rather than staring at one object.
  3. As the speed increases, a driver tends to look to the distance and overlook pedestrians or bicycles that dart out into the road from nearby. This is dangerous.
  4. As a driver drives longer time, his/her eyes are adjusted and overlooking is minimized. Therefore, he/she can drive safely.
  5. When a person suddenly enters a dark place from a bright place, his/her vision drastically declines temporarily. However, a person's vision does not change when he/she enters a bright place from a dark place.
  6. Never drive after drinking alcohol, because drunk driving can cause mistaking, overlooking, misjudgment, wrong operation, etc., which leads to an accident.

(正: right, 誤: wrong)