Unit 25 - Adverse Driving Conditions
Avoid flooded areas and flowing water, even if they occur along a road. The road bed may be blocked, disfigured, or otherwise unsafe beneath the water. Don't park your vehicle near a stream or other body of water—flash floods can strike quickly and without notice. Increase your alertness at night, when flooding is less noticeable.
A more common problem than flooding, however, is traction loss. This can happen in wet or dry weather, can be caused in a number of ways, and can affect the front wheels, the rear wheels, or all wheels. When your wheels lose traction against the ground, the way they behave is often called skidding. This refers to a common form of traction loss in which the tire loses rolling friction against the ground and begins to slide, or skid, across its surface.
It can be extremely helpful to carry the following items in your car: Jumper cables can bring a dead battery back to life. Being able to drive your car and use its radio, headlights, heater, and air conditioning is very important both day-to-day and in emergency situations. Road flares can help prevent a single collision from turning into a pile-up. Set up road flares to warn approaching drivers of a hazard.
A wireless radio enables you to hear emergency and weather reports when your car's battery is dead. A battery-operated radio is useful only as long as its batteries are kept in good condition. A hand-charging radio is more reliable over long periods of time and in foul weather. A fire extinguisher can help prevent a minor collision from becoming much more devastating. A five-pound fire extinguisher takes up little space, but can save lives. A first aid kit is essential when a person needs help before paramedics can arrive. A pen and notepad will help you record important information in the event of a collision.
In addition, tires with worn tread—less than about 1/16th of an inch—will provide very poor handling and traction. They are unsafe and should be replaced immediately.
All of your vehicle's components are important to safe operation, but some are affected more than others by adverse conditions. External lights are another example of this. Dirty or age-worn lenses on headlights, turn signals, and taillights can make your vehicle's lights nearly impossible to see in darkness or bad weather. Keep them free of dirt, and have them replaced if the lenses obscure your lights even when clean.
Bright light can be completely blinding, and can strike at any moment: A curve in the road brings the sun into view, blinding you. A passing car reflects sunlight directly into your eyes. An oncoming driver has his or her high-beams on in the rain, forcing you to narrow your eyes. You emerge from a dim tunnel into bright daylight, and your eyes take a few painful seconds to adjust.
Be prepared at all times to put on a pair of sunglasses, use your vehicle's sun visors, or squint and look towards the nearest lane line to your right. Keep your windshield clean, both inside and out—dirty windshields illuminate and reflect light into your eyes. A map or other piece of paper placed on the dashboard can also cause a bright reflection when hit by sunlight or another vehicle's high-beams.
A map will help to prevent confusion, wrong turns, and wasted time. Bottled water and nonperishable food are useful to prevent both boredom and starvation. Duct tape can be used to patch up a broken muffler, bumper, window, or side mirror.
Blankets are useful when your vehicle breaks down at night or on a cold day. A change of clothes will be very helpful if you have to exit a disabled vehicle in the rain. A flashlight is indispensable when stranded in a dark area. Towels are useful for drying things off, cleaning up dirt, and keeping people warm.
The cold air that comes with these conditions also affects your vehicle's tires in significant ways. For every 10° F that the temperature drops, pressure in your tires will fall by roughly 1 PSI. If you inflate your tires to have the correct pressure when the temperature is 70° F, they'll be significantly underinflated in 30° F weather. Underinflated tires greatly increase the risk of losing control and skidding. When inflating your tires, be sure to adjust them so that they'll have the correct pressure while they're actually operating on the road.
Cold temperatures also affect your vehicle's fuel, engine and other system hoses, and battery. If your vehicle isn't well maintained, you may suffer an unexpected breakdown when the temperature drops. Remember to keep your windows free of fog by turning on the defroster, turning off air recirculation, turning up fan speeds, and adjusting air temperature.
Before starting your car, scrape any ice or snow off of all windows. Remove chunks and thick layers of snow from all surfaces to prevent them from falling off and striking another vehicle while you're driving. As soon as snow begins to fall, activate your windshield wipers and low-beam headlights.
Drive in the center of your lane, and make sure to signal early so that your actions don't surprise other drivers. When driving near snow plows, give them extra room. The width of their plow may be difficult to determine. If you must pass a snow plow, do so only when you're sure it's safe, and only very carefully.
Make sure your headlights are aligned properly. Misaligned bulbs can shine into other drivers' eyes and fail to illuminate the road ahead of you. Low-beams should illuminate the road surface 100 to 150 ft ahead, and above the road 300 to 500 ft ahead. If you can't see past your low-beams, the highest safe speed is 40 to 45 mph. High-beams should illuminate the road surface 300 to 350 ft ahead, and above the road 500 to 1,800 ft ahead. If you can't see past your high-beams, the highest safe speed is 55 to 60 mph. Above these speeds, you're overdriving your headlights—creating an area ahead of your vehicle that is not illuminated and which you would enter before coming to a complete stop in an emergency braking situation.
Even with activated and properly-aligned headlights, you must remain alert and actively search the driving environment for information. In particular, you should: Pay attention to the contours of the road, making sure to stay in your lane and drive at a safe speed at all times Look for other road users, including pedestrians, animals, slow-moving vehicles, and unlit vehicles Find and obey all relevant traffic control devices, including STOP signs, lane lines, crosswalks, and expressway exit signs
Gusts of wind may strike suddenly as you pass large trucks, leave forests, ridges, or plateaus, or exit from an underpass or tunnel. Pay attention to the connection between your car and the ground, and watch for swaying trees or airborne objects. When driving in strong winds, slow down and increase following distance. Drive in the center of your lane, and grip the steering wheel firmly to keep control over your position.
Extreme heat presents a number of unique problems, and not just to older cars. High temperatures can cause discomfort and sleepiness, hindering your judgment and reflexes. You may also become dehydrated, which can cause a severe inability to concentrate. Your vehicle will also suffer from extreme heat. Components containing rubber or pressurized fluids will behave differently and wear more quickly. Tire pressure rises as air temperature increases, which can deform the shape of your wheels and reduce traction.
If you have difficulty seeing lane lines or other aspects of the road surface, drive in the tracks of the vehicle ahead of you. As long as it doesn't hit anything, you won't, either. Be careful when following this advice—you still need to pay attention to the road surface and to traffic around you. Conditions may change by the time your vehicle reaches the same location.
Finally, keep in mind that conditions can sometimes be so severe that driving at all is unsafe. If you can't see past the assured, clear stopping distance ahead of your vehicle, pull over and wait until conditions clear.
These safe driving practices will help you avoid emergencies, but they can't completely prevent them. Driving in rainy weather increases the probability of a number of different emergencies, including skidding, hydroplaning, and floods.
Floods are a serious issue, and we'll devote more time to this special situation in a later section. For now, consider the National Weather Service's advice: Turn Around, Don't Drown®. This phrase is also the name of a campaign to provide drivers with safety tips and early warning of floods. The National Weather Service recommends that you follow these rules to stay safe against flooding: Monitor a news or radio source, such as the National Oceanographic and Atmospheric Administration's Weather Radio, for weather conditions. Move to higher ground when flooding occurs.
Headlights and windshield wipers are essential in rainy weather. When rain or other debris falls on your windshield, turn on your windshield wipers. You need to be able to see clearly through the glass. When clouds make the road dim or dark, and whenever you turn on your windshield wipers, turn on your headlights. You need to be able to see the road ahead of you clearly. Activating your headlights will also help other drivers see you—and avoid you.
Foggy windows can make it very difficult to see out of your vehicle. Condensation develops on glass when the air on one side is significantly more humid than the air on the other side. You can help prevent condensation from forming by keeping your windows and windshield clean, both inside and out. However, if it does form, you'll need to get rid of it.
When driving in consistently cold weather—with daytime temperatures near 45° F or lower—you should consider equipping your vehicle with snow tires. Regular, "all-weather" tires typically are made of a rubber compound that stiffens and provides less traction as it becomes colder. Snow tires are composed of a different type of rubber that performs best in cold temperatures, providing better handling and braking ability. In addition, snow tires typically use a tread pattern that cuts through snow, ice, and water more efficiently, increasing traction and reducing the risk of skids. You can recognize approved snow tires by a symbol depicting a snowflake on a mountain.
For more extremely snowy or icy situations, driving safely requires the installation of snow chains. Attach one set to each of your vehicle's drive wheels, and to all four wheels when conditions are bad enough. Snow chains must be matched to your tire's diameter and tread width. They won't work if they're loose, and they'll break if you drive too far on dry pavement. Snow chains aren't for driving at full speed on snow and ice. Drive slowly and with extra caution when conditions call for snow chains.
The NHTSA reports that, in 2013, 48% of all fatal traffic collisions occurred during normal daylight conditions, while 88% occurred in clear weather. Driving in ideal weather and lighting conditions is already dangerous. Add rain, ice, darkness, fog, or even an earthquake to the equation, and it's easy to see that you need to take extra precaution to protect yourself in adverse conditions.
Fortunately, there are a lot of things you can do to prepare yourself. The first of these is something you should already be doing: keeping your vehicle properly maintained. Adverse conditions place more strain on your vehicle's engine, tires, and other components. Keeping these components in good condition will help you stay in control of your vehicle when the going gets rough.
Extreme temperatures can negatively affect your vehicle's fluids, rubber components, engine, starter motor, and battery. Make sure these components are kept in good condition. Many types of bad weather conditions also require the use of windshield wipers and wiper fluid. Replace worn wipers and check your wiper fluid reservoir regularly to ensure you can always see clearly through your windshield. Finally, keep your windshield clean, both inside and out. Dirty glass reflects light, obscuring your view when sunlight or other bright light shines through it.
Having certain tools on hand can make the difference between safely handling an emergency and being unable to prevent it from turning into a disaster. Because of this, storage space is a very valuable resource to a safe driver. By making use of the space in your trunk, you can prepare yourself for success in a number of different emergency situations.
Unfortunately, some parts of Texas are also susceptible to hurricanes, tornadoes, and earthquakes—and flooding is possible almost everywhere. Earthquakes strike without warning and typically don't last very long, but they can be catastrophically disruptive to the road surface and to the flow of traffic. If you feel the earth shaking, pull over as soon as possible and wait. Park somewhere with nothing overhead, with no danger of landslides or collapses. You'll usually have warning before hurricanes or tornadoes strike. If you do, stay off the road entirely—and if one strikes suddenly, find appropriate shelter as soon as possible. Never attempt to drive through a hurricane or tornado.
Hurricanes, regular rains, and the severe storms that often accompany tornadoes, can all cause flooding. Flooding is a big problem in Texas: according to the Flood Safety Education Project, Texas regularly leads the nation in deaths caused by flooding, and many of these deaths are vehicle-related. Roads aren't made to be submerged in water, and your vehicle isn't made to drive through it. When faced with flooding, stay out of the water. It's more important to find high ground than to go home—your best bet is to wait until conditions become stable, then find a safe way home.
If your vehicle becomes stuck in deep snow, keep calm. Before attempting to free your vehicle, find your exhaust pipe and clear snow away from the area around it. A blocked or smothered exhaust pipe can cause a deadly buildup of carbon monoxide inside your vehicle. To free your vehicle from the snow, point your front wheels straight ahead, shift into a lower gear—2nd in a manual transmission, or D2 in an automatic—and press the accelerator very gently. Press too hard and your wheels will spin freely against the snow without gaining traction.
If gentle acceleration isn't enough, increase throttle gradually. Sharp acceleration will cause your tires to lose traction against the snow. You may be able to move slightly forward, but fail to break free. If this happens, there are a few things you can do to help: Roll as far forward as possible in low gear, then shift into Reverse gear, and slowly accelerate backwards as far as you can. Shift into forward gear again, repeating this process and 'rocking' your vehicle back and forth until you break free. Place dirt, rocks, tree branches, or boards underneath your drive wheels. This makes it easier for your wheels to gain traction. Turn the steering wheel in different directions—some angles may give your wheels better traction, depending on the contours of the ground beneath them.
There are a number of myths about fatigue and driving, but here are the facts: Coffee won't keep you awake. You won't always know when you're about to fall asleep. Even a small amount of fatigue can be deadly when you're driving. A few hours of sleep isn't enough to keep you going through the following day and night. Music and open windows won't keep you from falling asleep. You can't force yourself to stay awake or alert indefinitely.
If you feel tired on the road, it's best to pull over and take a nap. If this is impossible, or if for any other reason you continue driving, you can help avoid a fatal collision if you: Sit up straight. If you lean forward, you'll have less control over your car and be more likely to fall asleep. Keep your eyes moving and check your mirrors frequently. Avoid overheating your car, even in the winter. Slow down and increase following distance so you'll have more time to react. Hum a song, chew a stick of gum, or have light conversation with passengers. Engaging your mind, but without distracting yourself from the road, can help you maintain awareness. Buckle your seat belt.
Never drive on ice if you can avoid it—you'll have almost no control over your vehicle's movement. Note that the road surface will be colder where buildings, trees, or other objects cast a shadow. Ice is more likely to form in these areas, and to remain icy even when other parts of the road have melted. Bridges and expressway overpasses will also freeze more quickly than other parts of the road. When it's cold out, slow down before driving over raised roadways.
It's important to avoid ice, but you may not always be able to see it. Black ice is a form of ice that develops very quickly, finishing smooth and almost completely clear. Black ice is often invisible from more than a few feet away. Prepare for this extremely treacherous form of ice by driving slowly at all times. Pay attention to the outside air temperature, and to road features like shadows and bridges.
When you see fog, slow down and increase following distance. Drive in the center of your lane and maneuver gently to avoiding losing control. Keep track of lane lines to prevent yourself from straying outside them. If water forms on the outside of your windshield, activate your wipers. Turn on your low-beam headlights as soon as you enter fog—high-beams will only illuminate the fog, making it more difficult to see. In areas with particularly poor visibility, turn off any music and roll down your windows to listen for nearby vehicles.
It's very important that you react to fog and slow down as soon as you see fog, and maintain a low speed even when driving in clear patches between fog banks. Some of the most deadly multiple-car collisions in the history of the United States happened when drivers speed up in a clear section of patchy fog. Above all, remember that if you can't see past the assured, clear stopping distance ahead of your vehicle, it's neither safe nor legal to continue driving. If visibility is poor enough, pull off the road. Park your vehicle outside of all lanes of traffic, activate your hazard lights, and turn the ignition to OFF. If your taillights remain visible, a confused driver might drive off the road thinking you were in a lane of traffic.
Becoming stranded in deep snow can be deadly. You'll have better chances of staying alive and being rescued if you: Stay inside your vehicle. You'll be warmer and have a much better chance of being located. Keep warm. Cover your head to conserve body heat, and perform some physical exercise regularly. Don't consume any alcohol—it lowers your body temperature. Run your car's heater for 15 minutes every hour, and use all available materials to increase insulation.
Make yourself visible. Activate your hazard flashers, tie a bright cloth to your antenna, and periodically turn on headlights and cabin lights at night. Prevent carbon monoxide poisoning. Clear snow from your exhaust pipe regularly, and don't run the engine unless a window is opened slightly.
Changes in traffic and lighting conditions also play an important role in altering levels of danger at night. The presence of fewer drivers, pedestrians, and sometimes police may make you feel like you no longer need to follow all the rules of the road. Despite this apparent increase in safety, more than half of all fatal traffic collisions occur between 6 p.m. and 6 a.m. In addition, the darkness of night, and even the dimness of dusk and dawn, all can greatly reduce your ability to properly see the road and its users.
Most drivers understand that they wouldn't be able to drive safely in darkness with their headlights off, no matter how hard they tried. But many believe that, by force of will, they can drive safely when fatigued. This faulty conception leads to great loss of life on America's roads. Fatigued driving is an even more prominent problem in Texas than in many other states: about 1 in 24 Texas drivers involved in fatal collisions are drowsy at the time of the crash. This figure is among the highest in the United States.
To clear fog from your windows in cold and rainy weather: Activate your car's defroster and turn off air recirculation. This helps move humidity outside of the vehicle. To clear fog as fast as possible, turn air speed to high and choose the lowest temperature setting. When dealing with mild fog, you can use hot air to evaporate the condensation while keeping the inside of your vehicle more comfortable.
Most roads have a positive cross slope—they're highest in the center and slope downwards toward the edges. Because of this, standing water will usually be more shallow near the center of the road, but deeper near the edge of the road. Keep this in mind when judging water depth.
Finally, remember: conditions may become so severe that it's not safe to drive. If you can't see farther than the distance it would take you to stop your vehicle, find a safe place to wait for conditions to clear. If snow, ice, or other conditions make controlling your vehicle too difficult, pull over.
Much like rain, winter weather increases the probability of traction loss. Recovering from a skid on snow or ice works much the same as a skid on wet pavement, but it can be far more difficult. Skids on snow or ice happen more easily, are less predictable, and are more severe. Because of the increased probability of traction loss, you must keep in mind that the actions of other drivers are less predictable. Go much more slowly and give other drivers much more space in order to avoid being involved in a collision.
Sudden or excessive acceleration, braking, and steering can also cause a loss of traction. Plan ahead and expect your maneuvers to take longer. Step softly on the accelerator and brake pedal, and make longer, softer turns rather than short, sharp ones. When the road is wet, it takes much less braking pressure to lose control. Always brake earlier than you would on dry pavement—it's far safer to brake softly and avoid skids entirely than to rely on ABS.
Never activate cruise control while driving in the rain or on a wet surface. If you begin to lose traction while cruise control is activated, your car will behave erratically. Modern speedometers determine vehicle speed based on the rate the drive wheels are spinning, not the rate at which the vehicle is moving relative to the ground. These two figures are the same under normal conditions, but disagree when traction is lost. When your drive wheels lose traction, they'll spin faster against the water without a corresponding increase in actual vehicle speed. This can result in the cruise control system executing a sudden cutoff in engine power, throwing your vehicle into an uncontrolled slide.
Falling rain and altered atmospheric conditions also affect the condition of your vehicle. Rain collecting on your windshield distorts your view through it, while the inside surface of your windows may develop an opaque layer of condensation, or fog.
Rain also typically coincides with clouds that block sunlight and make the roadway dim or dark. As we'll discuss in more detail later, darkness is not only dangerous because the road is less well lighted: it also reduces your ability to perceive depth, color, and detail.
In the following slides, you'll learn more about reducing risk when faced with adverse weather and lighting conditions. Keep this information in mind while driving, and implement it at the first sign of worsening conditions.
Rain is responsible for more fatal traffic collisions than any other adverse weather condition. The NHTSA reports that 7% of all fatal traffic collisions in 2013 occurred during rain. Rainfall has a serious impact on several aspects of the driving environment. Its presence in the air makes it more difficult for you to see, and you may also have difficulty hearing over the sound of rain drops striking your vehicle and the pavement.
When you hydroplane, or when your wheels spin against ice or another slippery surface, it may be more difficult to notice. Pay attention to the connection between your steering wheel and the actual steering of your vehicle. If steering feels loose, you may be losing traction. A sudden, unexpected rise in engine RPMs and speedometer reading without a corresponding increase in accelerator pressure or vehicle speed can also indicate that your wheels are spinning freely against water.
Recall how to safely recover from a skid: Release the accelerator and the brake pedal. Look, and steer gently, in the direction you want to go. When you feel your vehicle regain traction, gently apply the accelerator or brake. If your vehicle overcorrects and turns too far in one direction, keep looking where you want to go, and steer gently in that direction.
Fatigued drivers are more difficult to recognize, but a few signs will reveal them: Drifting across lane lines, then suddenly steering back in Gradually slowing down, then suddenly speeding up Late response to green lights, red lights, and STOP signs Bent or nodding head If you see a fatigued or impaired driver, pull over and call the police.
Remember that fatigue can cause impairment similar to what you'd experience when drunk or drugged. If you fall asleep, there's nothing to stop you from driving into oncoming traffic at 90 mph. But even if you stay awake, your judgment, focus and reaction time will be decreased—you won't be fit to deal with the increased dangers of driving at night. Next we'll discuss the causes of fatigue, as well as warning signs, myths, and coping mechanisms. This information may save your life one day.
The first thing you should do to increase safety when driving at night is simply to slow down—you'll have more time to see what you're driving toward, past, and next to. You'll also have more time to react when you see a STOP sign, pedestrian, or expressway exit. If you're driving behind another vehicle, increase your following distance to four or more seconds. Stay in the center of your lane and signal early before you turn or change lanes.
Remember that you must activate your headlights any time between half an hour after sunset and half an hour before sunrise. You must also activate your headlights whenever you're unable to see people or vehicles clearly from 1,000 ft. More than that, it's a good idea to activate your headlights whenever you have any difficulty seeing the road because of darkness. Use your high-beams when the road is dark enough and the air is clear, but not within 500 ft of an oncoming vehicle or 300 ft of a vehicle you're driving behind.
Similar in some ways to fog, particles like dust, sand, and smoke can also present serious problems to drivers. After slowing down, roll up your windows and recirculate air to prevent these particles from irritating your eyes and lungs. In dust or sand storms, road surface traction will be reduced. Settling particles may also obscure lane lines and the contours of the road. Turn on your low-beam headlights to allow yourself to see better, and to increase your vehicle's visibility to other drivers. After driving through dust, sand, or smoke, take your vehicle to a mechanic—these particles can cause serious damage to a number of engine, fuel, and ventilation components.
Strong winds can push a vehicle out of its lane—or off the road. Your vehicle will be less stable, and you'll have less control over it. Vehicles that are light, long, or tall are particularly vulnerable to strong winds. Some effects of strong winds may not less obvious at first. Wind can blow leaves and other objects through the air, reducing visibility, and can blow objects onto the road, causing hazards. It may even be difficult to hear over strong winds.
Never drive through water unless you're sure that it's less than one foot deep and not moving quickly. Partially-submerged objects can help you gauge water depth, but gradient and irregularities in the road surface make water deeper or shallower in some places than in others. Remember that the center of the road will usually be its highest point. Obey all warning signs. If a warning sign tells you to turn around, do so. Do not underestimate the power of standing or rushing water. Don't park near streams or rivers during rain or flooding.
The NOAA's active weather alerts website displays alerts such as tornado warnings, flash flood watches, and extreme fire danger alerts. You can learn about your region's specific susceptibility to flooding on the Flood Safety Education Project's website. If you are a resident of San Antonio, Austin, Waco, or Dallas, you're within a large area known as "flash flood alley." Please keep flood safety in mind, prepare yourself for the worst, and understand how to safely deal with flooding.
According to the NHTSA, more than half of all fatal collisions in 2013 took place at night, at dawn or dusk, or during conditions of semi-darkness. Relatedly, 46.5% of all fatal traffic collisions occurred between 3 p.m. and midnight. The most dangerous period of time was 6 p.m. to 9 p.m.: more than 4,800 fatal traffic collisions occurred during these hours in 2013, 25% more than at any time during daylight hours.
The human eye is poorly suited to night vision, suffering impairments in depth perception, color recognition, and peripheral vision. Judging speed and distance based on visual information is also more difficult in the dark. In addition, features of the driving environment are more difficult to discern. You'll have trouble seeing the contours of the road, lane lines, barriers, traffic signs, obstacles on the road, pedestrians, and other vehicles. Even headlights, necessary in dim or dark conditions, can be blinding and disorienting.
Fog can easily make driving extremely unsafe. When you encounter fog, be prepared to pull over. Fog can be unsettling and confusing to you as a driver. You may not be able to see past 100 ft, or even past 10 ft in the worst fog. The absence of sky, road, and environment can be extremely disorienting. Your windshield and rear and side windows may become foggy. Remember to turn the defroster on, recirculation off, fan speed up, and temperature down to quickly restore visibility.
The road may become damp and slippery in fog, reducing traction. Pay attention to the feel of your car's grip on the road. Other drivers may behave very differently. Some may pull off the road and stop, some may drive very slowly, and some may drive the speed limit. Some drivers may even become confused and drive against the flow of traffic. The air often becomes much dimmer in fog, presenting many of the same challenges as driving in darkness.
Staying in control means making sure that basic driver controls—steering, acceleration, and braking—remain in agreement with the road itself. To maintain this agreement, driver input is communicated to the road surface through your vehicle's tires. It follows that maintaining healthy tires is of utmost importance when driving in adverse conditions.
Underinflated tires wear down and blow out more quickly, and do a poorer job of transferring engine power and steering controls to the road. Overinflated tires are too stiff, reducing traction and making your ride harsher. Both types of improper inflation cause decreased handling and fuel economy in adverse conditions. Check your tire pressure regularly. Tires typically lose about 1 psi each month, and gain or lose about 1 psi for each 10° F change in temperature. Adjusting tire pressure is simple—most fuel service stations have inexpensive, self-service air pumps.
It's important to be able to recognize the signs of upcoming adverse conditions. Rainfall sometimes begins suddenly, but if you expect and prepare for rain whenever you begin to see dark clouds, you'll be ready for it. Similarly, snow or fog can sometimes begin very gradually, but if you respond to these conditions before they get worse, you'll be prepared any time your situation begins to present more of a threat.
Warning signs of imminent rainfall include dark clouds, increased wind, and a fine falling mist. It's particularly important to respond to these signs quickly because when rain first hits the surface of the road, it mixes with oils embedded in the surface and creates a very slippery film. Further rain will typically wash this oily mixture off the road's surface, but the rain itself still presents a danger to drivers.
You may become fatigued while driving if: You haven't had enough sleep You recently expended a lot of physical or mental energy You're driving for a long period of time or in a monotonous environment You're under stress You're ill or medicated You've just had a large meal Your vehicle is very warm
Warning signs that you're fatigued include: Blurred or unfocused vision Sore or tired eyes Difficulty keeping your eyes open Sore or tired muscles Difficulty keeping your head up Soreness or a tired feeling at the back of your head Stiff joints Difficulty concentrating Difficulty staying in your lane Lapses in short-term memory—such as being unable to remember what happened a few seconds ago
Finally, keep in mind that snow and ice don't just make it more difficult for you to drive—everyone else on the road is susceptible to these conditions in the same way. Watch out for other drivers losing control, taking longer to come to a stop, and having difficulty seeing the road or even your vehicle. Drive cautiously to avoid being struck by another driver.
When driving in snowy or icy conditions, slow down, increase following distance, and maneuver gently. The risk of losing traction is even greater than on wet roads, so drive even more slowly than you would in the rain. When you begin driving on snow or ice, test your brake response to check traction. As you drive, continue to pay close attention to the grip of your tires on the road. Drive particularly slowly through turns and near pedestrians.
Your vehicle's engine and battery will be taxed more than usual in hot weather, especially while running the air conditioning system. Engine stress, use of electronics, and high demands for cold air can cause your engine to stall or your battery to die. Drive smoothly in hot weather and use air conditioning judiciously. Change your route and avoid hills and slopes to save your engine some of the strain of accelerating and maintaining high speeds.
When driving through a desert, wear sunglasses, drink plenty of water, and make frequent stops. Pay attention to how you feel, keeping the possibility of heatstroke, dehydration, and exhaustion in mind. If you stop your car in hot weather, roll your windows down—their glass turns the inside of your vehicle into a greenhouse, raising temperatures dramatically.
The condition of the road itself changes in very important ways when rain begins to fall. These changes have drastic effects on your ability to accelerate, brake, and steer your vehicle. Water on the surface of the road reduces traction. Your vehicle's wheels will suffer a diminished ability to transfer engine power, braking power, and steering controls to the pavement.
When rain first begins to fall, it mixes with oils on the road surface and creates a slippery film that can easily cause you to lose control of your vehicle. Even when not mixed with oil, standing water resists forward movement and buoys your vehicle up and away from the road, further reducing traction. Many cars will begin to float in as little as one foot of standing water.
Hydroplaning is a more severe form of traction loss. When a wheel drives over a layer of water, it must push the water out of the way so that the rubber can gain traction against the road surface. When the wheel is spinning too fast and the tread fails to push water out of the way quickly enough, the wheel spins freely against the water without touching the road. This results in a severe loss of control.
When reacting to a loss of traction, early recognition of the emergency is crucial. The most intuitive way to detect a loss of traction is by road feel—the physical connection between your body and the car, and between the car and the road. When you begin to skid, you'll feel the difference in control. Overall, skids on dry pavement are typically easier to notice. They involve hard breaking, heavy acceleration, or turns taken too sharply or too fast. When you skid on dry pavement, you'll feel your tires scraping against the ground and sliding in an unexpected direction.
Mud, puddles, and even wet leaves also present a serious threat to your ability to control your vehicle. Puddles can affect a single wheel at a time, causing your vehicle to swerve. They may also hide large potholes. Mud and wet leaves can cause a sudden loss of traction. Mud is particularly dangerous because it may stick to your tires and splash onto your headlights or windshield, reducing their effectiveness.
When you encounter rainy weather while driving, slow down. This is the easiest and most effective action you can take to reduce risk. The faster your vehicle's wheels spin, the less traction they have against the road's surface. When the road is wet, traction is reduced even further. By slowing down, you increase traction, enabling you to accelerate, brake, and steer reliably.
The road may feel more lonely at night, but it's not empty. There will always be pedestrians, other motor vehicles, or even police officers along your route. Obey the rules of the road just as you would in heavy traffic. Some road users are more common at night than at other times. Importantly, these include large trucks, drunk drivers, and fatigued drivers.
You can recognize an impaired driver by the following common behaviors: Driving too fast or too slow Sudden, sharp steering, acceleration, or braking Poor vehicle positioning, including driving on the curb, straddling lane lines, weaving between lanes, crossing into opposing lanes, or driving onto the shoulder Stopping in the wrong place or at the wrong time Signaling incorrectly, or failing to signal Driving with headlights off in darkness or dim light
If you encounter intermittent patches of fog while driving, slow down just as you would for a consistent blanket of fog. Many of the most deadly and most damaging multiple-vehicle traffic collisions in the history of the United States have occurred during fog. Often, drivers report that they had been driving full speed through patches of fog, when visibility suddenly dropped nearly to zero. Fog is dangerous and unpredictable. Don't underestimate it.
You should also respond quickly when lighting conditions begin to dim. Activate your vehicle's low-beam headlights when the sky becomes darker due to cloud cover or sunset. Driving without your headlights on in dim light endangers yourself and other drivers, and is illegal.