Psychological and Physiological Issues for Drivers
The car isn't the only thing that can have "breakdowns." The driver must also be in top condition to safely operate on today's highways.
In order to drive safely, you must be in good physical condition. In particular, you need to be able to see and hear well enough to detect potential hazards and handle emergency situations.
Vision plays a key role in the steps by which you detect and avoid a hazardous situation, which include:
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Good vision is key to being able to stop your vehicle in time to avoid an accident.
Under good conditions you need 200 - 300 feet to stop at 55 mph and 100 - 150 feet to stop at 35 mph.
This implies that you can't drive safely at 55 mph unless you can see at least 300 ft, or 35 mph if you can't see at least 150 feet.
Central vision is used to discern detail and identify or recognize what is being seen.
Visual acuity is the finest detail that may be perceived, and is based on your "central" vision.
Visual acuity is important for reading road signs and identifying hazards. When you include your Field of Vision (central plus peripheral, as shown in the image above), you have a much larger "picture" of the road ahead, for identifying hazards and other information.
Peripheral or side vision is the field of view that surrounds the central portion of the visual field. You can see things most clearly directly ahead while things to each side (your peripheral vision), are less distinct. If your peripheral vision is severely limited, it can seriously affect safe driving ability unless it is compensated for by increased scanning and visual search.
Peripheral vision is used in part to detect information that may be important for safe driving. This kind of information includes road signs, appearances of hazards, and changes in the flow of traffic. When a driver notices something important, the driver moves his or her head and eyes to look at the object or event of interest.
Peripheral vision is also used in controlling the vehicle. When a driver looks in the rear-view mirror, peripheral vision is used to monitor traffic in front of the vehicle. In keeping the vehicle centered in the lane, peripheral vision is used to monitor the lane boundaries and keep the vehicle oriented in traffic.
Poor peripheral vision can result in:
A person who can read 3/8-inch high letters clearly from a distance of 20 feet is considered to have normal vision and is said to have 20/20 vision.
A person with, say, 20/40 vision must be 20 feet from the eye chart to read what a person with normal vision would be able to read at 40 feet.
The DMV uses Snellen wall charts (letter charts) and an optical device, the Optec 1000 vision tester, to screen driver license applicants for a best-corrected distance visual acuity of no worse than 20/40.
No matter how good your peripheral vision is, there will still be areas to the sides and behind your vehicle that cannot be seen. These areas are referred to as blind spots.
Other vehicles, especially small ones such as motorcycles, are easily hidden in your blind spots.
Using your rear view mirror will not eliminate all blind spots, so when changing lanes you need to check for vehicles in your blind spot by turning your head and looking into the lane you want to enter.
Large vehicles such as trucks have more extensive blind spots than small vehicles.
Trucks have even larger blind spots, often called NO ZONES. You should never linger in these no-zones when passing a truck. Wait until the lane is clear enough to pass the truck, and/or accelerate to pass.
Depth perception is your ability to correctly perceive the distances of objects in relation to your own position. Depth perception is important when passing, approaching a vehicle or obstruction, and in turning.
Poor depth perception can result in:
Traffic circles are an excellent example of the need for depth perception. Upon approaching the circle, a driver must use depth clues to determine his or her entrance speed, and whether a complete stop will be required, or a yield.
Upon entering the circle, especially one with multiple lanes, the driver must get depth clues about the speed and distance of other cars already in the circle, as well as those preparing to enter.
Night vision refers to your ability to see well in low light levels and is necessary for being able to drive safely at night. The visual ability of two drivers may be about the same during daylight hours, but be markedly different at night.
Driving safely at night requires seeing well not only under low illumination, but also requires being able to see low contrast objects. A person wearing dark clothing and crossing the street in front of a driver is much harder to detect at night because there is much less contrast at night between the darkly-clothed pedestrian and the dark background.
Poor night vision while driving at night can result in:
Glare is intense and blinding light. For example, glare caused by the brightness of oncoming headlights can prevent a driver from seeing an approaching vehicle or pedestrian crossing the roadway.
Glare resistance is the extent to which a driver can still see objects and events while facing a steady source of glare such as the setting sun or the light from oncoming headlights.
Glare recovery is the speed with which a driver's vision returns to normal after being exposed to glare. Glare resistance and recovery are important for being able to drive safely during sunset or at night.
Glare resistance and recovery deteriorate with age; older drivers must drive more cautiously at night.
Poor glare resistance and recovery can result in a driver being blinded by a glare source and:
Color blindness is the inability to accurately and consistently distinguish between certain colors such as those at traffic lights and on signs. If severe, color blindness may affect a driver's ability to drive safely.
The image on the right is what a traffic light can look like to a person with color blindness.
A person can compensate for poor visual acuity by wearing glasses or contact lenses prescribed by a ophthalmologist or optometrist.
A person can compensate for poor depth perception by using extra caution in judging the speed and distance of oncoming vehicles and approaching objects.
A person can compensate for poor peripheral vision by frequently turning the head to increase his or her field of vision.
A person can compensate for poor glare resistance and recovery while driving by using the sun visor, wearing sun glasses or other dark lenses during the sunset, and by avoiding looking into the headlights of oncoming cars.
A person can compensate for color blindness while driving by learning the general shapes and patterns of signs, and relying on the position of signal lights, rather than on their color.
If you wear glasses...
Whenever you drive, you must wear the glasses or contact lenses that have been prescribed for you or are required by a restriction on your license.
You should never wear dark glasses at night and you should consult a physician regarding the safety of wearing tinted contacts at night.
You should not wear glasses whose frames or lenses obstruct your peripheral vision.
Aging and vision
Certain aspects of vision deteriorate slowly with age, sometimes so slowly that people do not notice the change. It is important to have your eyes checked every year or two by an optometrist or ophthalmologist to ensure that you are not putting yourself or others at risk while driving.
Putting stickers, signs, and other objects on your windows can adversely affect your vision. You may only place these things:
Exceptions are allowed for persons with sensitivity to light to use sun-blocking devices, if they have a note from a doctor or optometrist.
In addition, vehicles with both left and right outside mirrors, which allow the driver to see 200 feet to the rear of the vehicle, are exempt from the restrictions on the rear window. These mirrors are also required when towing a trailer, camper, or other vehicle that reduces your ability to see behind you.
The five abilities required for being a safe driver are sometimes referred to as SIPDE:
Safe driving cannot be accomplished if one or more of these abilities are missing. These abilities relate to a driver's perception, judgment, and motor function.
A driver must be able to search and identify:
These abilities relate to the driver’s perception.
A driver must be able to predict the action that a potential hazard might take. This ability also relates to the driver's perception.
For example, if you see an oncoming vehicle with its left turn signal on, can you predict that it might turn in front of you?
A driver must be able to decide what action to take if the potential hazard becomes an actual hazard. This ability relates to the driver's judgment.
For example, if the vehicle with its left turn signal on does turn in front of you, can you make a safe driving decision? Should you brake or swerve to avoid the hazard?
A driver must be able to execute the driving maneuver that is required to handle the potentially hazardous traffic situation. This ability relates to the driver's motor function.
After you've decided what action to take, do you have the strength, reactions, reflexes, and the physical ability to maneuver the vehicle safely out of danger?
If any one of these abilities is missing or deficient, you cannot be a safe driver. You will be deemed too dangerous to the motoring public and not given a license if:
Hearing is more important for safe driving than many people realize. Your hearing can warn you of dangers, such as the presence of vehicles in your blind spots, it allows you to respond to someone honking their horn, emergency vehicle sirens, and bells at railroad crossings, and can alert you to impending engine or other mechanical failure.
A hearing impairment (partial deafness) is the inability to hear low to medium (softer) decibel sounds, or sounds of certain frequencies.
Deafness is the inability to hear even the loudest of sounds.
A person can compensate for a hearing impairment and improve his or her ability to drive safely by seeing a doctor and having a hearing aid prescribed to amplify sounds. A person with a hearing impairment or total deafness can also compensate by learning to rely more on vision, such as increasing the degree to which they visually scan their environment.
Auditory acuity deteriorates with age. It is important to have your hearing checked periodically by a doctor because often changes in hearing occur so slowly that people do not notice them.
To hear properly while driving a vehicle you should:
Except for drivers of certain types of special equipment and law enforcement, a person must not wear a headset or earplugs that cover both ears while driving.
When you are tired, you are less alert. The body naturally wants to sleep at night and most drivers are less alert at night, especially after midnight. You may not see hazards early enough, or react as quickly.
Therefore, you increase your chances of being in a collision if you are tired or fatigued.
If you are tired, the only safe cure is to get off the road and get some sleep. If you don't, you risk your life and the lives of others. To keep from getting tired on a long trip:
Illness can impair your ability to transmit visual and auditory information to the brain, impair the ability of the brain to act on it, impair your ability to rapidly take corrective action, such as changing the direction and speed of your vehicle, and can cause you to fall asleep at the wheel.
Certain prescription and over-the-counter medications taken for illness, even common cold medications, can cause you to become drowsy while driving.
Deformities, Steadiness, Muscular Conditions
Deformities and loss of limbs can prevent you from driving safely. There are prosthetic appliances and special controls for vehicles that allow persons with a disability to drive as safely as any other person.
Being unable to keep your muscles steady, which can be caused by Parkinson's Disease, a stroke, or as a part of the normal aging process, can prevent you from safely stopping and maneuvering a vehicle, particularly in emergency situations.
Having inadequate muscular strength, such as is caused by Cystic Fibrosis or the normal aging process, can prevent you from being able to adequately maneuver road curves and turns, affecting your ability to drive safely.
Disqualifying Conditions for Obtaining a License
Depending on severity, certain physical and mental conditions may prevent you from obtaining a driver license. These conditions include:
However, if you can compensate for a physical condition, usually by demonstrating safe driving ability during a driving test, a driver license can be issued.
Carbon monoxide is an odorless gas produced by gasoline-powered engines. Therefore, you will not be able to know if you are breathing it. If you breathe too much carbon monoxide, you will become carbon monoxide poisoned.
If you have carbon monoxide poisoning, your ability to see, hear, and think will be severely diminished, which can cause you to have an accident. If you become severely poisoned from continued ingestion of carbon monoxide, you will die.
Carbon monoxide can be brought into the car by leaks in the exhaust system or through an open window or ventilating system.
Do not run your vehicle's engine in an enclosed space, such as a garage, without properly ventilating the area. Have your exhaust system periodically checked for leaks to prevent yourself from becoming carbon monoxide poisoned.
Drivers ages 15 to 19 have very high traffic accident, injury, and conviction rates.
Drivers under age 18 are 2.5 times more likely to have a fatal accident than the average driver.
Nearly half of drivers who start driving before they are age 20 are convicted of a traffic violation within their first year of driving.
Teenage drivers have total accident rates which are twice that of adults.
Traffic accidents are the leading cause of death for teenagers.
Having the physical ability to operate a motor vehicle is really only half the picture. Being in the right psychological state - that is, having the right attitudes, traits, and motivation - is also essential to driving safely, being courteous, and avoiding accidents and traffic citations.
Young drivers' over-involvement in traffic accidents stems from lack of driving experience, exposure to accident risk, alcohol/drug consumption, perceptual abilities, inexperience identifying and handling hazardous situations, personality structure, internal and external influences, poor judgment, excessive speed, and attitudinal factors such as risk-taking propensity.
Being ready to drive involves more than just checking your vehicle equipment and having a license. You have to be mentally prepared for different traffic conditions and have gained all the necessary knowledge, skills, and abilities through practice and training courses. To drive safely you have to have readiness, which is to be completely focused on the task at hand.
You have to be motivated to learn and apply safe driving attitudes. You need to first be motivated to learn how to be a safe driver in driver education and training, and then be motivated to apply what you have learned to actual driving situations. Not all drivers will drive as safely as you do; you have to be motivated to have a safe driving attitude, regardless of other drivers' behavior towards you.
Young drivers are more willing to take risks compared to other drivers; they are more likely to perceive hazardous situations as being less dangerous than they actually are.
Although drivers under age 25 have the fastest simple reaction times, they respond to traffic hazards more slowly than do mid-age drivers, suggesting that they frequently fail to recognize situations as being potentially hazardous.
Young drivers overestimate their capabilities; drivers ages 18 to 24 perceive themselves as being less likely than other drivers their age to be involved in an accident.
Young drivers rate certain traffic situations as less risky than do mid-age and older drivers, especially situations involving darkness, graded or curved roadways, intersections, and rural environments.
Teens tend to underestimate the danger in high-risk situations and to overestimate the danger in low- to medium -risk driving situations.
Establish Good Habits Through Practice
The facts on the previous pages demonstrate that teens do not do a good job of judging their skill level or the dangerousness of driving situations. It is important that you and the people who teach you how to drive analyze and identify the problem attitudes and behaviors you exhibit while driving. For example, do you tend to visually-search less often after you have been driving for a while than when you begin driving? You should constantly monitor yourself while you are driving to identify poor driving habits and attitudes.
Once you identify a poor driving habit or attitude, you should substitute the appropriate behavior or point of view. You must continuously practice that appropriate behavior or point of view until it becomes automatic. For example, if you recognize that you start to slack in your visual-scanning over time, you should remind yourself to do so continually during your driving, until it becomes something you automatically do all the time.
You need to repeatedly practice correct responses to hazards while learning how to drive. Remember that only training and practice can overcome poor driving habits and attitudes.
Maintain Good Habits Through Performance
Established good driving habits and attitudes can slowly deteriorate over time (drift). In other words, just because you have good driving habits and attitudes now does not mean you will have them in the future. You need to continue to check yourself while driving, even after you have your license, to identify and correct areas where your habits and attitudes have slipped.
Remember to practice doing the correct behavior and having the correct attitude. Only through continued analysis and application of appropriate habits and attitudes can you effectively maintain your good driving habits in the future.
There are a number of characteristics that can affect your psychological ability to focus on the driving task, and react safely and courteously. These characteristics include:
Your emotional state influences your ability to concentrate, stay alert, be courteous, think clearly and rapidly, contain anger and aggressiveness, and control tendencies to "show off."
Safe driving requires all your concentration If you are preoccupied with your emotions, you will not be able to focus on the task of driving safely. Therefore, you should not drive if you are under severe tension, emotionally distressed (e.g., depressed, angry or upset), or otherwise preoccupied with your emotions, thoughts or personal problems.
Being late to work or to an appointment can also cause you to become stressed, and hence drive unsafely. Being late for an event is not an excuse to drive poorly. The few minutes you may make up by weaving in and out of traffic or by speeding are unlikely to make a difference anyway. The best thing to do is just accept the fact that you are going to be late, and plan better next time to avoid finding yourself in the same situation.
Conditions of the environment both inside and outside your vehicle can also affect your ability to concentrate, be courteous, and drive safely.
Conditions outside of your vehicle, such as heavy traffic, bad weather, and road work can cause you to become stressed, especially if you are in a hurry. There is usually very little that you can do to alleviate the situation. If you find yourself in this situation and notice that you are becoming stressed, get off the road and make a phone call to inform someone that you are going to be late.
Become familiar with routes you are going to drive and the traffic conditions on the route at different times of the day. In the future, allow extra time when driving that route, or try another one instead.
Chronic traffic congestion is the California commuter's biggest headache, but even small changes in driving habits could provide relief of traffic congestion. Avoid doing the following:
If another driver does something to make you angry, take a few deep breaths and do not react aggressively. Remember that people just sometimes make mistakes (including you) and forget about it.
Conditions inside of your vehicle, such as distracting passengers, loud music, and doing other things while driving can also cause you to drive unsafely. Driving is a complex task that requires your full attention.
If you have a parent who tends to drive aggressively or be inattentive while driving, you should take steps to make sure that you do not pick up or express his or her poor driving habits. Some characteristics are passed genetically or through modeling others' behavior, and only proper training and practice can overcome poor traits that are passed-on from your parents.
Family (and friends) may not necessarily be good drivers; avoid using them as role models if they do not practice safe driving habits.
Illnesses or injuries can negatively affect your ability to concentrate on safe driving. Be aware of the effects of the medications you take for illness or injuries before you get behind the wheel; you will be held responsible for their effects on your driving.
Proper training through driver education and training and through practice on the road will make you more comfortable with driving. When you first begin, you will likely be nervous about your ability level.
As good driving behaviors and attitudes become automatic through practice, you will be better able to enjoy driving. When you see others who are just learning how to drive, be courteous and remember how nervous you were the first time you got behind the wheel.
There are a number of traits which are dangerous while driving, and they include:
Aggressiveness (Road Rage)
Aggressive driving is often referred to as "road rage." Road rage happens when one driver reacts negatively to another driver. Angry drivers may lash out at other drivers, including you.
Road rage is characterized by a driver using their vehicle in an angry and aggressive manner such as:
Anger and driving don't mix. Behind the wheel is no place for aggression. But more and more people are letting their emotions get the best of them. One recent report states that during the first six years of the 1990's, over 10,000 incidents of road rage were reported. People zigzagging in and out of traffic, someone cutting someone else off, and tailgating for long distances can lead to collisions, disputes, and even death. Impatience is one of the prime causes leading to risk-taking, discourteous driving and disputes. Being more patient behind the wheel will go a long way to keeping you out of the reach of road rage.
You can avoid situations leading to road rage by:
If you find yourself in a situation with an aggressive driver, avoid making eye contact. To some people, eye contact is the same as a challenge. If someone is determined to act out his or her frustrations, even a friendly smile can be misinterpreted. Give the angry driver plenty of space. If you make a driving error (even accidentally), it is possible the other driver may try to pick a fight with you. Put as much distance between your vehicle and the other car as you can, even by changing routes, if necessary.
Do not be aggressive towards other drivers when you are on the road. Be patient when other drivers make mistakes and avoid getting frustrated by giving yourself extra time to get to your destination and being aware of road conditions so that you can take an alternate route.
If you think you are being followed, don't drive home. You would only be telling your follower where you live. You should:
Egotism is the same thing as being self-centered. People who are egotistical feel like they own the road and do not consider the rights of other drivers. The heart of egotism is disrespect for other drivers on the road.
Drivers who are egotistic tend to engage in speeding, risk taking, unsafe rapid starts, and aggressive behavior. Egotistical drivers do not make room for merging vehicles, do not yield the right-of-way, do not let other drivers pass, follow emergency vehicles too closely or fail to yield to them, and cut off other drivers by merging at too slow or too fast of a speed.
Remember that all drivers share the road. Be aware of and courteous to other drivers, and they will be more likely to be courteous to you.
Being angry or upset while driving can result in inattentiveness, aggressive behavior, poor judgment, and poor vehicle control.
If you are angry or upset, do not drive your vehicle. You will not be able to give safe driving the full attention that it requires. Make sure to calm down before you get behind the wheel.
For your safety and the safety of others, you should give driving your full attention. If you are distracted by psychological or situational factors, even for just a split second, you will not be able to react to hazards as quickly and it could result in a serious accident.
Distractions that can lead to accidents include:
You should leave an extra cushion of space around your vehicle for persons who are likely to be distracted. Some examples include:
Cellular telephones are everywhere. In an emergency they can be a lifesaver. In non-emergency situations they can be a great tool if you use the cellular phone in a safe and responsible manner.
Research has shown that drivers are at a much higher risk for being in an accident within a few minutes of using a cellular phone. Surprisingly, it appears that it is the emotional impact of the phone conversation, not the act of talking per se, that results in increased accident risk.
Minors and Cell Phones
You may use a cell phone to contact law enforcement, a health care provider, the fire department, or another emergency entity in an emergency situation.
More from the DMV...
Here's a DMV video about California "hands free" cell phone laws. Pay special attention to how the law applies to persons under 18 years of age.
Most evidence suggests that the number one factor in young drivers' over-involvement in accidents is risk-taking. Young drivers often "show off" to impress their friends or others, which can lead to serious injury and death.
Exhibition on the road by speeding, weaving your vehicle back and forth, starting out from a signal too fast, peeling out, street racing other drivers, passing dangerously, playing "chicken," and failing to obey signals and the rules-of-the-road, needlessly causes accidents.
Driving is a serious responsibility that requires mature behavior. If you can't drive like an adult, stay off the road.
As a driver, you must take responsibility for your actions, the actions of your passengers, and for the safe mechanical condition of your vehicle.
Teens who engage in higher-risk activities outside the driving situation tend to have higher traffic accident involvement, whether they are driving or riding as a passenger, suggesting that risky driving may be part of a more general syndrome of risk-taking behavior.
Safe driving requires:
Your life and the lives of your passengers are in your hands while you are driving. If you act irresponsibly, such as by drinking and driving, you are putting more than just your own life at risk. Think before you act or get behind the wheel.
More from the DMV...
For more food for thought, view this DMV video about bad decision making (not required for course completion).
You may continue to the lesson quiz at any time.
You will now answer 5 questions to test what you learned during this lesson. You must answer all questions correctly to receive completion credit for this lesson. You may answer the questions as many times as necessary to get them right.
You should review the lesson material if you don't do well on the quiz.
*Check with your California insurance agent for eligibility details. Every licensed California Driver must have auto insurance to drive a vehicle in California. Proof of insurance must be provided to the California DMV when you obtain your drivers license (not your learners permit).