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Winter Safety Briefing by SWR
- 2. You must understand how cold weather effects your vehicle before, during, and after operation. Winter Safety Briefing
- 3. Before beginning your journey during wintery weather conditions: • Ask yourself if your journey is absolutely essential. • Check local and national weather forecasts. • Listen to local and national radio for travel information. • Tell someone what time you expect to arrive. • Think about taking warm clothes, boots, and a flashlight – it could be a long walk to a phone. • Clear your windows and mirrors of snow and ice before you set off. Winter Safety Briefing
- 5. Winter sun Dazzle from winter sun can be dangerous! If it's too low for the visor, it might be worth keeping a pair of sunglasses handy WEAR QUALITY SUNGLASSES Good quality sunglasses help highlight changes in the terrain and road surface, even in low visibility conditions Winter Safety Briefing
- 6. Dress Properly Wear several layers of thick, loose-fitting clothing. Wear a hat, scarf, and turtleneck sweater. The head and neck lose heat faster than any other part of the body. Dress for the cold. Don’t forget a hat and gloves. Winter Safety Briefing
- 7. Wear warm clothes that do not restrict movement. In bad weather, let someone know your route and intended arrival time, so you can be searched for if you don't turn up after a reasonable delay. Prepare the Driver Winter Safety Briefing
- 8. Wear several layers of loose fitting, lightweight clothing. Wear mittens instead of gloves. Wear a hat. Remember that entrapped, insulating Winter Safety Briefing
- 9. With the temperature of 5°F and winds blowing at 35 mph, the wind chill index would be -21°F, which could cause frostbite within 45 minutes. (Increased DangerIncreased Danger) With a temperature of -20°F and winds blowing at 35 mph, the wind chill index would be -55°F and could cause frostbite in less than 5 minutes. (Great DangerGreat Danger) Examples of wind chill: Read right and down from the calm-air line. For example, a temperature of 0ºF combined with a 20 mph wind, has an equivalent cooling effect of -22ºF. Winter Safety Briefing
- 10. 10
- 11. PREPARE FOR THE TRIPPREPARE FOR THE TRIP Winter Safety Briefing
- 12. Routine precautions help you avoid starting problems: Get an engine tune-up in the fall Be sure all lights are in good working order Have the brakes adjusted Remember to switch to winter-weight oil if you aren't already using all-season oil Battery and voltage regulator should be checked Dirty oil can give you trouble in the winter, so change the oil and filter. Check the other filters, including the fuel, air and transmission filters. Vehicle Preparation Winter Safety Briefing
- 13. Make sure battery connections are good. If the battery terminal posts seem to be building up a layer of corrosion, clean them with a paste of baking soda and water. Let it foam, and then rinse with water. Apply a thin film of petroleum jelly to the terminal posts to prevent corrosion, and reconnect. Wear eye protection! Be sure all fluids are at proper levels. Winter Safety Briefing Vehicle Preparation
- 14. Antifreeze should not only be strong enough to prevent freezing, but fresh enough to prevent rust. Make sure wiper blades are cleaning properly. Consider changing to winter wiper blades, which are made for driving in snow. They are covered with a rubber boot to keep moisture away from working parts of the blade. Clean frost and snow off the windows, mirrors, lights and Winter Safety Briefing Vehicle Preparation
- 15. Carbon monoxide, present in exhaust fumes, is almost impossible to detect and CAN BE FATAL when breathed in a confined area. Because of the danger of carbon monoxide poisoning, don't let your car warm up in the garage for a long period of time, especially if you have an attached garage. The fumes easily can seep into the house and overcome those inside, even with an open garage door. http://www.phymac.med.wayne.edu/FacultyProfile/penney/COHQ/co1.htm Carbon monoxide. Winter Safety Briefing Vehicle Preparation
- 16. The exhaust system: Have the exhaust system checked fully for leaks that could send carbon monoxide into your vehicle. Heating and cooling system: Check your radiator and hoses for cracks and leaks. Make sure the radiator cap, water pump, and thermostat work properly. Test the strength of the anti-freeze, and test the functioning of the heater and defroster. Winter Safety Briefing Vehicle Preparation
- 17. Windshield: Make sure wipers are in good condition and fill up on winter washer fluid. Keep extra in your trunk. Ensure your windshield can give you clear vision of the road and traffic around you. One way to find a good repair facility to tune-up your vehicle is to look for an ASI Approved Auto Repair Services sign at garages or ask a friend. Winter Safety Briefing
- 18. DON’T FORGET TO FILL UP WITH FUEL Winter Safety Briefing
- 19. Snow shovel. Scraper with a brush on one end. Tow chain or strap. Warning device (flares or reflective triangles). Brightly colored cloth to signal for help. Here's what you'll want to have on hand, especially in an emergency: Don’t forget the gloves. Your fingers will stick to cold metal. Winter Safety Briefing
- 20. Flashlight (with extra batteries) Abrasive material (cat litter, sand, salt, or traction mats). Compass, Warning light or road flares, Booster cables First Aid Kit Here's what you'll want to have on hand, especially in an emergency (Con’t): Keep the headlights on while driving. Don't use your bright lights because the snow can reflect light back into your eyes. Winter Safety Briefing
- 22. Better understand the dangers of winter storms. Better identify current and future hazardous weather conditions based on current weather information that is received. Think critically through a weather situation and make intelligent decisions based on the reliability of that weather information. Better understand the personal responsibility for one’s decisions during adverse winter weather and the consequences that may follow. Winter Safety Briefing
- 23. Winter Deaths Everyone is potentially at risk during winter storms. The actual threat to you depends on your specific situation. Recent observations indicate the following: Related to ice and snow: About 70% occur in automobiles. About 25% are people caught out in the storm. Majority are males over 40 years old. Winter Safety Briefing
- 24. FFLURRIESLURRIES - Light snow falling for short durations.- Light snow falling for short durations. No accumulation or light dusting is all thatNo accumulation or light dusting is all that is expected.is expected. SSHOWERSHOWERS - Snow falling at varying- Snow falling at varying intensities for brief periods of time.intensities for brief periods of time. Some accumulation is possible.Some accumulation is possible. SSQUALLSQUALLS - Brief, intense snow- Brief, intense snow showers accompanied by strong,showers accompanied by strong, gusty winds. Accumulation maygusty winds. Accumulation may be significant.be significant. Weather
- 25. BBlowing snow –lowing snow – Wind-driven snow thatWind-driven snow that reduces visibility and causes significantreduces visibility and causes significant drifting. Blowing snow may be snow that isdrifting. Blowing snow may be snow that is falling and/or loose snow on the groundfalling and/or loose snow on the ground picked up by the wind.picked up by the wind. HHeavy snow –eavy snow – 10 cm (4 in.) or10 cm (4 in.) or more in 12 hours, or 15 cm (6more in 12 hours, or 15 cm (6 in.) or more in 24 hours, andin.) or more in 24 hours, and snow falling reduces visibility upsnow falling reduces visibility up to a quarter of a mile or less.to a quarter of a mile or less. Weather
- 26. Snow is frozen precipitation in the form of six-sided crystals. Snow is produced when water vapor is deposited directly into o airborne particles as ice crystals, which remain frozen as they fall. When temperatures remain below freezing from the cloud to the ground, snow results. Weather
- 27. Progressing even further away from the warm front, surface temperatures continue to decrease and the sleet changes over to snow
- 28. Snowflakes are simply aggregates of ice crystals that collect to each other as they fall toward the surface
- 29. Blizzard - The most perilous of winter storms combining falling, blowing, drifting snow, winds of 40 km/hour or more, visibility less than 1 km, temperatures less than –10o C; duration: six hours or more. Cold Wave - A rapid fall in temperature in a short period, requiring greater than normal protective measures. Winds - The cause of blizzard conditions, drifting, reduced visibility and wind-chill effects. Weather
- 30. Sleet falls to earth as ice pellets. These ice pellets are formed as snowflakes melt into raindrops as they pass through a thin layer of above-freezing air. The rain drops than refreeze into particles of ice as they pass through a sub-freezing layer of air near the ground.
- 31. Progressing further ahead of the warm front, surface temperatures continue to decrease and the freezing rain eventually changes over to sleet. Areas of sleet are located on the colder side (typically north) of the freezing rain band. Weather
- 32. Sleet is less prevalent than freezing rain and is defined as frozen raindrops that bounce on impact with the ground or other objects. Weather
- 33. Sleet is more difficult to forecast than freezing rain because it develops under more specialized atmospheric conditions. It is very similar to freezing rain in that it causes surfaces to become very slick, but is different because its easily visible. Weather
- 34. Visualize a baseball (Hail) dropped from a 747 flying at 30,000 feet; it's speed reaches 120 MPH, visualize you going 70 MPH under this big ugly cloud......bam! Weather
- 35. ICE Expect icy conditions any time the outside air temperature reaches 40o F or lower. Although water freezes at 32o F, road surface can freeze when the air temperature drops to 40o F or less. An important place to watch for this condition is on bridges. Bridge surfaces are exposed to the wind and cool off faster than the rest of the road. You should also prepare for icy conditions on roads through shaded areas where a cold wind can freeze a wet road surface. Weather
- 36. Freezing rain is caused by rain droplets that freeze on contact with the ground or objects near the ground, leaving a frozen glaze. The temperature of the ground must be below freezing, and the rain droplets must exist in a liquid state at temperatures below freezing for freezing rain to occur. Freezing rain can glaze roadways with ice causing extremely hazardous driving conditions. Weather
- 37. Ice storms can be the most devastating of winter weather phenomena and are often the cause of automobile accidents, power outages and personal injury. Ice storms result from the accumulation of freezing rain, which is rain that becomes super cooled and freezes upon impact with cold surfaces. Freezing rain is most commonly found in a narrow band on the cold side of a warm gront, where surface temperatures are at or just below freezing. Weather
- 38. The diagram below shows a typical temperature profile for freezing rain with the red line indicating the atmosphere's temperature at any given altitude. The vertical line in the center of the diagram is the freezing line. Temperatures to the left of this line are below freezing, while temperatures to the right are above freezing. Weather
- 40. Always test your road When you first pull out onto the road, if there is no traffic, you should tap the brakes to see if there is a reaction. Be sure to let off the brakes immediately if the tires slide so you don't lose control. Attempt this a few more times to experiment with how hard you can brake without putting your car into a skid. You can also accelerate a bit to see how much it will take to make the drive wheels spin. Be sure to let off the accelerator if the tires do spin so you don't lose control.
- 41. MAINTAIN A COMFORTABLE DRIVING ENVIRONMENT - A constant flow of cool air will help to keep you alert, and keep the windows clear of frost. Keeping one window slightly open will allow you to hear sirens and other warning sounds more quickly. Avoid large bulky boots, gloves, and coats, and never drive in ski boots.
- 42. BLIND SPOTSBLIND SPOTS ADJUST MIRROWSADJUST MIRROWS Make sure all windows are clean and there is nothing blocking your vision. Adjust the seat so you can reach all pedals and controls easily. Adjust the inside and outside rearview mirrors. Fasten safety belts and shoulder harnesses so that they are firm and comfortable. BLIND SPOTS
- 43. CHECK YOUR BLIND SPOTSCHECK YOUR BLIND SPOTS BEFORE CHANGING LANESBEFORE CHANGING LANES BLIND SPOTS
- 44. 1. Unbelted and too close 2. Use seatbelt 3. Recline back of seat 4. Move seat rearward 5. Tilt wheel down 6. Correct belted 10” or more away Seat Belts/ AirbagsSeat Belts/ Airbags
- 45. Aggressive driving can be observed in the following driving patterns: speeding, tailgating, failure to yield, weaving in- and-out of traffic, passing on the right, making improper and unsafe lane changes, running stop signs and red lights, making hand and facial gestures, screaming, honking, and flashing lights. This type of driving can be associated with being impaired by alcohol or drugs and/or poor anger management. Aggressive Driver
- 46. ANTICIPATE DIFFICULT SITUATIONS - Studies show that 80% of all accidents could be prevented with only one more second to react. In many situations, this one second can be gained by looking far enough down the road to identify problems before you become a part of them.
- 47. TURN ON YOUR LIGHTS - Whenever daytime visibility is less than ideal, turning on your lights allows you to see, and to be seen by others. Remember this rule of thumb, Wipers On - Lights On. When traveling in snowy weather, remember to clear tail lights, signal lights, and headlamps regularly.
- 48. According to the National Highway Traffic Safety Administration (NHTSA), sport utility vehicles have the highest rollover rate of any vehicle type in fatal crashes: 37 percent as compared with 25 percent for pickups, 19 percent for vans and 15 percent for passenger cars. SUVs also have the highest rollover rate in injury crashes - 9 percent as compared with 7 percent for pickups, 4 percent for vans and 3 percent for cars.
- 49. MANY PEOPLE BELIEVE - that quick reactions make a good driver. The world's best drivers are trained to anticipate problems early and direct the vehicle appropriately before they become involved in a problem. Reacting too quickly can be dangerous if the driver's response is inappropriate. Driver Reaction
- 50. Studies have shown that pedestrians walking along a road in dark clothing at night are first seen approximately 55 feet away giving the driver less than one second reaction time. A driver traveling at 60 MPH needs over 260 feet to stop. Pedestrian Traffic
- 51. Initial speed Stopping distance Stopping time km/h mph Meters Feet seconds 40 25 36 118 5.4 45 28 46 151 6.0 50 31 52 170 6.6 55 34 62 203 7.1 60 37 72 236 7.7 65 40 83 272 8.2 70 44 95 311 8.8 75 47 108 354 9.3 80 50 121 397 9.9 90 56 150 492 11.0 100 62 182 597 12.1 110 68 217 712 13.2 120 75 256 840 14.3 130 81 297 974 15.4 140 87 341 1118 16.6 150 93 389 1276 17.6 Stopping Distances and Stopping Times at -2.5 m/s2 Stopping Distance
- 52. ADJUST YOUR SPEED TO THEADJUST YOUR SPEED TO THE CURRENT CONDITIONSCURRENT CONDITIONS - When driving inWhen driving in challenging conditions,challenging conditions, SLOW DOWNSLOW DOWN!! Decreasing your speed will allow more timeDecreasing your speed will allow more time to respond when a difficult situation arises.to respond when a difficult situation arises. Factors such as the type of vehicle you areFactors such as the type of vehicle you are driving, the quality of snow tires your car isdriving, the quality of snow tires your car is equipped with, and your abilities as a driverequipped with, and your abilities as a driver should all be considered in the speedshould all be considered in the speed adjustment.adjustment. Adjusting Speed
- 53. Wheel Spin Manual transmission car, starting out in 2nd gear may produce less wheel spin than 1st gear due to less engine power being applied to the wheels Let up on the accelerator or push in the clutch when you feel the tires break loose and start to spin. When the wheels stop spinning and catch hold, then you apply power again very gently.
- 54. Snow that has been compacted during the day and has slightly melted will freeze at night. Usually this white ice can be seen on the road. When traveling on white ice, drive very slowly. If you cannot find a place to park until conditions improve, install tire chains for better traction. Slick trick -- Watch for slippery spots called glare ice. These may appear on an otherwise clear road in shaded areas. If you see a patch of ice ahead, brake before reaching it and try not to brake while actually on the ice WHITE ICE
- 55. Black Ice Black ice fools drivers. Its shine tricks them into thinking it's water on the road. What they may not realize is that condensation, such as dew, freezes when temperatures reach 32o F or below. This forms an extra-thin layer of ice on the road. This shiny ice surface is one of the most slippery road conditions. Black ice is likely to form first under bridges and overpasses, in shady spots and at intersections.
- 56. The jury is still out on whether rapid pumping of the brake pedal is more effective on slick surfaces than applying a soft steady pressure on the pedal, letting off just before the tires begin to slide. Of course, if the latter method is attempted and the tires do begin to skid, the driver must immediately let off the pedal and recover by steering in the direction of the skid. BRAKING
- 57. Watch out for fog - it drifts rapidly and is often patchy Drive very slowly using dipped headlights. Use fog lights if visibility is seriously reduced, but remember to switch them off when visibility improves. Don't hang on to the tail lights of the vehicle in front. This gives you a false sense of security and means you may be driving too close. Don't speed up suddenly - even if it seems to be clearing, you can suddenly find yourself back in thick Driving in Fog
- 58. When do I use Fog Lights? Fog lights are designed to be used during fog or foul weather, in conjunction with your low beams to focus as much light as possible on the ground directly in front of you. Providing increased light on the ground helps you to follow the road and helps reduce the reflection on the fog from your headlights. Driving in Fog
- 59. Fog Safety Tips: Drive with lights on low beam Reduce speed Avoid crossing traffic unless absolutely necessary Listen for traffic you cannot see Driving in Fog
- 60. Fog Safety Tips (Con’t): Use wipers and defroster as necessary for maximum vision. Be patient! Don’t pass lines of traffic. Unless absolutely necessary, don’t stop on any freeway or other heavily traveled road. Consider postponing your trip until the fog clears. Driving in Fog
- 61. WHEN DRIVING AT NIGHT - Leave your headlamps on low beam when driving in snow or fog. This practice minimizes the reflection and glare, improves visibility, and reduces eye fatigue. When oncoming cars approach, focus on the right side of the roadway to help maintain good night vision. Nighttime Driving
- 62. Risk Management Reminders Prepare a Driver If you must drive in bad weather, plan ahead and make sure you have enough fuel. See and be seen; clear all snow from the hood, roof, windows and lights. Clear all windows of fog and moisture. If visibility becomes poor, find a place to safely pull off the road as soon as possible. Risk Management
- 63. It is most important to remember to slow down when the roads get slippery, and to practice anticipating what could be coming around the next curve. You have no control over who is behind the wheel of that vehicle approaching you. If you are going so fast that you are on the edge of control yourself, you will have no margin of error if the other driver suddenly loses control of their vehicle. Slow down and live!
- 64. Hand in hand with winter comes heavy rain, fog, ice and snow. Bad weather affects visibility and stopping distances. Follow this ten-point plan and be a safer winter driver. 1. Allow extra time for your journey and reduce your speed. 2. Increase the distance between you and the vehicle in front, and be certain you can stop within the distance you can see to be clear. FOLLOW THE TEN-POINT PLAN FOR SAFER WINTER DRIVING
- 65. 3. If visibility is seriously reduced by fog, use low beam headlights and fog lights. Switch on your wipers to keep your windscreen clear. 4. Remember to turn fog lights off when they are no longer needed as they can be a distraction to other drivers. 5. Remember the obvious - you can see snow, but you can't always see ice. 6. Avoid sudden braking, accelerating too quickly and harsh steering in slippery conditions. FOLLOW THE TEN-POINT PLAN FOR SAFER WINTER DRIVING
- 66. 7. Keep your windshield clear of snow and check from time to time that there is not a build up of snow on your lights. 8. Carry a shovel, extra warm clothing, a blanket, a snack and a drink - especially if you are traveling through isolated areas. 9. If you are going on a long journey, advise someone of your destination and what time you expect to arrive. 10. If you feel uncomfortable driving in bad weather, consider whether your journey is really necessary or whether you can go by an alternative to the car. FOLLOW THE TEN-POINT PLAN FOR SAFER WINTER DRIVING
- 68. 68 Presented by Lt. Col John Kruger SWR Safety Director Winter Safety Briefing References: www.us.army.mil www.nws.noaa.gov
Editor's Notes
- Objective: Students will be able to prepare their vehicle for winter operation and identify what is a winter storm and the terms associated with one (freezing rain, sleet, blizzards, heavy snow, squalls, etc.). Students will be able to make a plan for themselves and what they should do during a winter storm. Lesson Activities: 1. Begin by asking the students to brainstorm different types of problems they may have had in the past winter months. 2.The instructor should have the students explore various classroom station, each looking at a type of winter weather,.) 3.lists emergency type items, not just extra things Accommodations: This lesson requires the students to work together in a groups. The students will also be provided with many hands-on activities during this lesson so that learning will take place by not just listening and reading, but through exploration. Teaching Information: The term winter storm covers a broad range of weather conditions (ex: blizzard, heavy snow, snow squalls, snow showers, snow flurries, freezing rain, and sleet). A blizzard is snow and blowing snow with winds at least 35 miles per hour and stronger gusts creating snow drifts. Heavy snow is at least four inches - six inches of snow need to fall within a 12 hour period. Snow Squalls are a sudden snow burst, like a mini blizzard happening in a small area, not affecting a whole region. Snow Showers are similar to that of a rain shower, but instead of rain it is snow. Snow Flurries are a light shower of short duration spreading a dusting of snow over the area. Freezing Rain is when the ground temperature is cold than that of the atmosphere and what starts as rain, freezes as it falls to the ground -- one of the most dangerous of the winter storms events for driving and walking. Sleet is balls of ice that form when raindrops fall from the warm air of the atmosphere and go through a cold layer near the Earth's surface, thus covering the ground with ice balls.
- Students will be able to prepare their vehicle for winter operation and identify what is a winter storm and the terms associated with one (freezing rain, sleet, blizzards, heavy snow, squalls, etc.). Students will be able to make a plan for themselves and what they should do during a winter storm. INSTRUCTOR WILL CONTINUE DISCUSSION FROM PREVIOUS SLIDE. INSTRUCTOR WILL INTERJECT PERSONAL EXPERIENCES WHILE DISCUSSING DRIVING IN EXTREME WEATHER CONDITIONS.
- Wind Chill Equivalent Index The Wind Chill Equivalent Index is an air temperature index that measures the heat loss from exposed human skin surfaces. Heat loss is caused by a potentially lethal combination of wind and low air temperature. The actual air temperature is not as low as the Wind Chill Equivalent Index. Wind removes heat from the body in addition to the low temperature. Risk of frostbite from low wind chill indices makes the wind chill a winter weather hazard
- Objective: Students will be able to prepare their vehicle for winter operation and identify what is a winter storm and the terms associated with one (freezing rain, sleet, blizzards, heavy snow, squalls, etc.). Students will be able to make a plan for themselves and what they should do during a winter storm. Lesson Activities: 1. Begin by asking the students to brainstorm different types of problems they may have had in the past winter months. 2.The instructor should have the students explore various classroom station, each looking at a type of winter weather,.) 3.lists emergency type items, not just extra things Accommodations: This lesson requires the students to work together in a groups. The students will also be provided with many hands-on activities during this lesson so that learning will take place by not just listening and reading, but through exploration. Teaching Information: The term winter storm covers a broad range of weather conditions (ex: blizzard, heavy snow, snow squalls, snow showers, snow flurries, freezing rain, and sleet). A blizzard is snow and blowing snow with winds at least 35 miles per hour and stronger gusts creating snow drifts. Heavy snow is at least four inches - six inches of snow need to fall within a 12 hour period. Snow Squalls are a sudden snow burst, like a mini blizzard happening in a small area, not affecting a whole region. Snow Showers are similar to that of a rain shower, but instead of rain it is snow. Snow Flurries are a light shower of short duration spreading a dusting of snow over the area. Freezing Rain is when the ground temperature is cold than that of the atmosphere and what starts as rain, freezes as it falls to the ground -- one of the most dangerous of the winter storms events for driving and walking. Sleet is balls of ice that form when raindrops fall from the warm air of the atmosphere and go through a cold layer near the Earth's surface, thus covering the ground with ice balls.
- PREPARE YOUR CAR Before you depart on a winter trip, make sure your car is in good mechanical condition. Ask your repair shop to inspect the hoses and belts as well as the electrical, exhaust and coolant systems. Test your headlights, turn signals and flashers. Make sure the seat belts and wiper blades operate properly. Change the oil and oil filter every 3,000 miles and rotate the tires on schedule. Check the inflation on your spare tire and keep your container of windshield washer fluid full.
- CHECK YOUR BATTERYPay particular attention to your car battery because it is a common cause of on-the-road problems. Today's batteries don't require water, but make sure that the terminals ends are clean and free of corrosion and that the cable connections are secure. Carefully monitor the condition of any battery more than two years old. Replace any battery more than four year old.
- What is Carbon Monoxide? Carbon monoxide (CO) is a colorless, odorless, poisonous gas. A product of incomplete burning of hydrocarbon-based fuels, carbon monoxide consists of a carbon atom and an oxygen atom linked together. Why is Carbon Monoxide a Public Health Problem? Carbon monoxide enters the bloodstream through the lungs and forms carboxyhemoglobin, a compound that inhibits the blood's capacity to carry oxygen to organs and tissues. Persons with heart disease are especially sensitive to carbon monoxide poisoning and may experience chest pain if they breathe the gas while exercising. Infants, elderly persons, and individuals with respiratory diseases are also particularly sensitive. Carbon monoxide can affect healthy individuals, imparing exercise capacity, visual perception, manual dexterity, learning functions, and ability to perform complex tasks. In 1992, carbon monoxide levels exceeded the Federal air quality standard in 20 U.S. cities, home to more than 14 million people. How is Carbon Monoxide Formed? Carbon monoxide results from incomplete combustion of fuel and is emitted directly from vehicle tailpipes. Incomplete combustion is most likely to occur at low air-to-fuel ratios in the engine. These conditions are common during vehicle starting when air supply is restricted ("choked"), when cars are not tuned properly, and at altitude, where "thin" air effectively reduces the amount of oxygen available for combustion (except in cars that are designed or adjusted to compensate for altitude). Nationwide, two-thirds of the carbon monoxide emissions come from transportation sources, with the largest contribution coming from highway motor vehicles. In urban areas, the motor vehicle contribution to carbon monoxide pollution can exceed 90 percent. What's Been Done to Control Carbon Monoxide Levels? The Clean Air Act gives state and local governments primary responsibility for regulating pollution from power plants, factories, and other "stationary sources." The U.S. Environmental Protection Agency (EPA) has primary responsibility for "mobile source" pollution control. The EPA motor vehicle program has achieved considerable success in reducing carbon monoxide emissions. EPA standards in the early 1970's prompted automakers to improve basic engine design. By 1975, most new cars were equipped with catalytic converters designed to convert carbon monoxide to carbon dioxide. Catalysts typically reduce carbon monoxide emissions upwards of 80 percent. In the early 1980's, automakers introduced more sophisticated converters, plus on-board computers and oxygen sensors to help optimize the efficiency of the catalytic converter. Today's passenger cars are capable of emitting 90 percent less carbon monoxide over their lifetimes than their uncontrolled counterparts of the 1960's. As a result, ambient carbon monoxide levels have dropped, despite large increases in the number of vehicles on the road and the number of miles they travel. With continued increases in vehicle travel projected, however, carbon monoxide levels will begin to climb again unless even more effective emission controls are employed. What Else Is Being Done? Carbon monoxide emissions from automobiles increase dramatically in cold weather. This is because cars need more fuel to start at cold temperatures, and because some emission control devices (such as oxygen sensors and catalytic converters) operate less efficiently when they are cold. Until 1994, vehicles were tested for carbon monoxide emissions only at 75¡ F. But recognizing the effect of cold weather, the 1990 Clean Air Act calls for 1994, and later, cars and light trucks to meet a carbon monoxide standard at 20¡ F as well. The 1990 Clean Air Act also stipulates expanded requirements for Inspection and Maintenance programs. These routine emission system checks should help identify malfunctioning vehicles that emit excessive levels of carbon monoxide and other pollutants. The inspections will be complemented by requirements for on-board warning devices to alert drivers when their emission control systems are not working properly. Another strategy to reduce carbon monoxide emissions from motor vehicles is to add oxygen-containing compounds to gasoline. This has the effect of "leaning out" the air-to-fuel ratio, thereby promoting complete fuel combustion. The most common oxygen additives are alcohols or their derivatives. Several Western U.S. cities have successfully employed wintertime oxygenated gasolines for many years. The 1990 Clean Air Act expands this concept and requires that oxygenated gasolines be used during the winter months in certain metropolitan areas with high carbon monoxide levels
- basic supply kit--flashlight, jumper cables, flares or reflective triangles, hand tools, and gloves--is absolutely essential. But it is not enough protection if your car is disabled in winter weather.
- Objective: Students will be able to prepare their vehicle for winter operation and identify what is a winter storm and the terms associated with one (freezing rain, sleet, blizzards, heavy snow, squalls, etc.). Students will be able to make a plan for themselves and what they should do during a winter storm. Lesson Activities: 1. Begin by asking the students to brainstorm different types of problems they may have had in the past winter months. 2.The instructor should have the students explore various classroom station, each looking at a type of winter weather,.) 3.lists emergency type items, not just extra things Accommodations: This lesson requires the students to work together in a groups. The students will also be provided with many hands-on activities during this lesson so that learning will take place by not just listening and reading, but through exploration. Teaching Information: The term winter storm covers a broad range of weather conditions (ex: blizzard, heavy snow, snow squalls, snow showers, snow flurries, freezing rain, and sleet). A blizzard is snow and blowing snow with winds at least 35 miles per hour and stronger gusts creating snow drifts. Heavy snow is at least four inches - six inches of snow need to fall within a 12 hour period. Snow Squalls are a sudden snow burst, like a mini blizzard happening in a small area, not affecting a whole region. Snow Showers are similar to that of a rain shower, but instead of rain it is snow. Snow Flurries are a light shower of short duration spreading a dusting of snow over the area. Freezing Rain is when the ground temperature is cold than that of the atmosphere and what starts as rain, freezes as it falls to the ground -- one of the most dangerous of the winter storms events for driving and walking. Sleet is balls of ice that form when raindrops fall from the warm air of the atmosphere and go through a cold layer near the Earth's surface, thus covering the ground with ice balls.
- II. IntroductionThis weather exercise has been designed to cover some of the basic skills needed to stay safe driving during winter storms. The same principles apply to any region of the country.More importantly, it will also develop or extend their ability to think critically during adverse weather situations and understand the risks involved when traveling in the winter months in areas where winter winter can claim lives.
- The diagram shows a typical temperature profile for snow with the red line indicating the atmosphere's temperature at any given altitude. The vertical line in the center of the diagram is the freezing line. Temperatures to the left of this line are below freezing, while temperatures to the right are above freezing Since the snowflakes do not pass through a layer of air warm enough to cause them to melt, they remain in tact and reach the ground as snow.
- The diagram shows a typical temperature profile for sleet with the red line indicating the atmosphere's temperature at any given altitude. The vertical line in the center of the diagram is the freezing line. Temperatures to the left of this line are below freezing, while temperatures to the right are above freezing.
- A picture of Hail that hit a wind shield
- Freezing rain develops as falling snow encounters a layer of warm air deep enough for the snow to completely melt and become rain. As the rain continues to fall, it passes through a thin layer of cold air just above the surface and cools to a temperature below freezing. However, the drops themselves do not freeze, a phenomena called supercooling (or forming "supercooled drops"). When the supercooled drops strike the frozen ground (power lines, or tree branches), they instantly freeze, forming a thin film of ice, hence freezing rain.
- Objective: Students will be able to prepare their vehicle for winter operation and identify what is a winter storm and the terms associated with one (freezing rain, sleet, blizzards, heavy snow, squalls, etc.). Students will be able to make a plan for themselves and what they should do during a winter storm. Lesson Activities: 1. Begin by asking the students to brainstorm different types of problems they may have had in the past winter months. 2.The instructor should have the students explore various classroom station, each looking at a type of winter weather,.) 3.lists emergency type items, not just extra things Accommodations: This lesson requires the students to work together in a groups. The students will also be provided with many hands-on activities during this lesson so that learning will take place by not just listening and reading, but through exploration. Teaching Information: The term winter storm covers a broad range of weather conditions (ex: blizzard, heavy snow, snow squalls, snow showers, snow flurries, freezing rain, and sleet). A blizzard is snow and blowing snow with winds at least 35 miles per hour and stronger gusts creating snow drifts. Heavy snow is at least four inches - six inches of snow need to fall within a 12 hour period. Snow Squalls are a sudden snow burst, like a mini blizzard happening in a small area, not affecting a whole region. Snow Showers are similar to that of a rain shower, but instead of rain it is snow. Snow Flurries are a light shower of short duration spreading a dusting of snow over the area. Freezing Rain is when the ground temperature is cold than that of the atmosphere and what starts as rain, freezes as it falls to the ground -- one of the most dangerous of the winter storms events for driving and walking. Sleet is balls of ice that form when raindrops fall from the warm air of the atmosphere and go through a cold layer near the Earth's surface, thus covering the ground with ice balls.
- According to the National Highway Transportation Safety Administration, a large and growing number of highway accidents are caused by the non-detection of an object beside a vehicle when switching lanes.. Try It: It Works! Some of the most serious preventable accidents occur because of blind spots while driving. Now there is a remarkable simple solution discovered by an engineer named George Platter. He presented his method at the prestigious Society of Automotive Engineers. The National Safety Council tested his theory and discovered, to their amazement, that it works! The method has been tested and fully endorsed by the National Safety Council as described in their September/October issue of Traffic Safety. Here's how it works. First, forget how we learned to adjust our outside mirrors by plopping behind the steering wheel and turning the mirrors so that we just saw the side of our car looking back at us in the mirrors. Instead, adjust the driver's side mirror by resting your head against the driver's side window and then turning the mirror so that you just see the side of your car. Once this is set, move to the center of the vehicle and turn the passenger side mirror so that you can just see the side of your car from the center of the vehicle. That's it. You won't see your own car in either mirror, yet what you will see is far better. Cars behind you show up as usual in the inside rearview mirror above the dash, but the instant the car leaves your field of vision from the rearview mirror the outside mirror picks it up. No. blind spot; no delays; no wondering where that car about to pass you has disappeared to--and no waiting a few seconds for the car that you just saw in your rearview mirror to show up in your outside morrors. All three mirrors work in harmony with one another, and the blind spot has been elminated!" Here's how it works: First, forget how we learned to adjust our outside by plopping behind the steering wheel and turning the mirrors so that we just saw the side of our car looking back at us in the mirrors. Instead, adjust adjust the driver's side mirror by resting your head against the driver's side window, and then turning the mirror so that you just see the side of your car. Once this is set, move to the center of the vehicle and turn the passenger side mirror so that you can just see the side of your car from the center of the vehicle. That's it. !!!!! You won't see your own car in either mirror, yet what you will see is far better. Cars behind you show up as usual in the inside rear-view mirror above the dash, but the instant the car leaves your field of vision from the rear-view mirror, the outside mirror picks it up. NO BLIND SPOT; no delays; no wondering where that car about to pass you has disappeared to: and no waiting a few seconds for the car that you just saw in your rear-view mirror to show up in your outside mirrors. All three mirrors work in harmony with one another, and the blind spot has been eliminated!"
- Position your seat in the most rearward position which provides a safe and comfortable reach to the brake and accelerator pedals. All occupants should ride with their backs against the seatback, restrained by the seat belts to maximize the effectiveness of the air bag and reduce the risk of injury from being too close to an inflating air bag. Move your seat to the rear as far as you can while still reaching the pedals comfortably. If your steering wheel is adjustable, tilt it downward. This points the air bag toward your chest instead of your head and neck. ——
- SUVs - While sport utility vehicles perform well in many difficult driving conditions, drivers of these popular vehicles still need to exercise caution to help ensure safe winter driving. While the higher ground clearance and four-wheel drive might help SUV owners get going in heavy snow, those special features do not help stop the vehicle. Drivers still need to slow down and increase the distance between vehicles when driving on slick roads. It is also important to know if a sport utility vehicle has anti-lock brakes so that proper braking techniques can be used. SUV owners need to realize that their vehicles have different handling characteristics than other passenger vehicles.
- Assumed and included is a response time (driver, brakes) of 1 s. Note: The deceleration -2.5 m/s2 is only typical for strong braking and whether it is in good judgment depends on conditions that only the driver can judge. A vehicle gets decelerated -2.5 m/s2, whether from braking on a horizontal surface or idling up on a 25 % grade. Also, under the same brake action, the vehicle decelerates only -1.5 m/s2 on a down grade of 10 %. This makes a stopping distance of 78 m, an increase of 50 %, when compared with 52 m on the horizontal. This demonstrates the enormous hazard of a speed not properly adjusted for conditions. One can generalize as follows: x m/s2 is the braking reduction one gets on a 10 x % down grade.
- All drivers are conditioned to the feel of their car thrusting forward when they let off the brake and push down on the accelerator (automatic transmission) or let out the clutch (manual transmission) on dry or wet pavement. The driver habitually applies this same power to the drive wheels of their car when they are on snow and ice, and gets nowhere -- fast. The natural impulse is to "give it more gas" when the vehicle doesn't move forward as it should, and the bad situation is worsened. The friction created by the spinning tire builds up heat, which melts the snow or ice, creating a microscopic lubricating film of water between the tire and the snow or ice. How do you know when the tires begin to spin? Short of noticing that your vehicle is failing to make forward progress, there are two tips to help you recognize that your tires are spinning. First of all, you need to listen. To do this adequately, you may need to turn off the radio, CD or tape player, heater blower, windshield wipers, etc. to be able to hear them or the drive train. Also, you might need to roll down the driver's side window, if it isn't iced shut, at least until you are making forward progress. Another indicator is the speedometer. If the speedometer indicates that you are going 10-25 miles per hour but the vehicle doesn't seem to be moving forward, it could be that your drive wheels are spinning. If you have a manual transmission car, starting out in 2nd gear may produce less wheel spin than 1st gear due to less engine power being applied to the wheels let up on the accelerator or push in the clutch when you feel the tires break loose and start to spin. When the wheels stop spinning and catch hold, then you apply power again very gently
- Glatteis – GERMANY WORD A particular hazard of driving in Europe in the winter time is the danger of "black ice" or Glatteis. The best way to recognize black ice is by surface reflection, but that dull patch just ahead might be ice also. Be especially wary in the early morning or late evening and near or on bridges. If you see the patch, take your foot off the gas quickly. Once on an icy section, do not accelerate, brake, gear down or make any sudden change in direction. Keep well behind other cars. If starting to lose control, steer toward the edge of the road where residues of sand and salt might help.
- In recent years, car manufacturers have taken to the habit of placing "fog" lights (also called "driving" lights) on new cars. These can be very useful if designed correctly. They can also be very dangerous if designed poorly. When I was younger, I thought it looked very cool to drive around with all my lights on (now I know where the expression "running around with his headlights on" came from). I figured that if I put all the lights on, everyone would see me. I also thought it made the car look "cool", whatever that means (forgive me, we all were teenagers once). But what I failed to recognize was my fog lights didn't have the desired effect at all. Particularly on a clear day, they were blinding to oncoming traffic, as well as the people driving in front of me, having the opposite effect and making it harder for me to be seen. When I moved to Europe, I studied some of the driving laws and discovered they took a very different approach to the use of fog lights. Fog lights are generally for FOG and must only be used in visibility of less than 100 yards (meters). The rear foglight (usually a single red light as bright as a brake light) could only be used in visibility of less than 50 yards (meters). Of course, they are called fog lights because rarely in normal rain or snow does your visilbility drop to such a dangerous level like it can in fog. When there is fog, you have little chance of seeing an adequate distance, particularly on the highway. That is why you must drive so much slower in the fog. This can be a VERY scary feeling. Many times I would drive the Autobahn in thick fog, aware of the news stories of horrible fog accidents (nebel unfalle), worried that I would be part of the next 100-car pile-up. In this situation, fog lights can save your life. Many fog lights on American cars are designed very poorly. Unfortunately, this is also true for many Japanese and European imports. As they are mostly unregulated, fog lights that are not an integral part of the car's lighting, which usually hang from a bumper, require extreme precision to insure proper positioning. If even slightly out of adjustment, these can blind oncoming traffic. Therefore, it is essential that they are adjusted properly, and are only used when necessary. If you can justify use of the fog lights at any other time, I'd love to hear from you. I doubt you'll be able to convince me otherwise. So, if you want to be thought of as a courteous driver, don't light up your car like a Christmas tree. Make sure all the normal lights (markers, directionals, parking lights and low/hi beams) are working - that is adequate. Put on your headlights in the rain. Use the fog lights when you have very low visilibility, and don't forget to turn them off when the fog has lifted! All those that have to share the road with you will genuinely appreciate your kind consideration.
- Question: Why are fog lights yellow? Does it help that they are? Does it matter if you are driving in city or countryside? jessica v. Answer: My understanding is that it is important for fog lights to be one color (rather than white, which is all colors) because the different wavelengths(colors) of visible light scatter off the fog droplets differently. This phenomenon is known as "dispersion," because the different colors of light in an image will separate from each other, causing the image to "disperse." If you illuminate the road with only one wavelength (color) of light, the images of the objects you see will still become somewhat blurry because of the scattering of light by the fog, but at least you won't have extra problems from dispersion. So, if we want to use just one wavelength of light, which wavelength should we use? It turns out that light with short wavelengths scatters more than light with long wavelengths (short to long: violet, indigo, blue, green, yellow, orange, red). So, a long wavelength light will be best. There's another thing to consider, too: our eyes are not equally sensitive to all colors. It turns out that we are most sensitive to yellow and green light. So, our best compromise between sensitivity for our eyes and a long wavelength for least scattering is yellow light. Now, I don't know what kind of light bulbs are used in fog lights, but another consideration used in street lighting is cost and efficiency. You may have seen some yellow street lighting in some places; this is "low-pressure sodium vapor" lighting. The special thing about this light is that it is almost entirely one (actually two very close together) wavelength of yellow light, and that it gives the most illumination for the amount of electricity. A big problem with this light, though, is that it throws off color perception. Under sodium vapor light, something blue looks gray. This makes it hard to, say, recognize your car in a parking lot. Richard Barrans Jr., Ph.D. ========================================================= There is no good reason why fog lights are yellow. Here is an excellent explanation provided by Professor Craig Bohren of Penn State University: "First I'll give you the wrong explanation, which you can find here and there. It goes something like this. As everyone knows, scattering (by anything!) is always greater at the shortwavelength end of the visible spectrum than at the longwavelength end. Lord Rayleigh showed this, didn't he? Thus to obtain the greatest penentration of light through fog, you should use the longest wavelength possible. Red is obviously unsuitable because it is used for stop lights. So you compromise and use yellow instead. This explanation is flawed for more than one reason. Fog droplets are, on average, smaller than cloud droplets, but they still are huge compared with the wavelengths of visible light. Thus scattering of such light by fog is essentially wavelength independent. Unfortunately, many people learn (without caveats) Rayleigh's scattering law and then assume that it applies to everything. They did not learn that this law is limited to scatterers small compared with the wavelength and at wavelengths far from strong absorption. The second flaw is that in order to get yellow light in the first place you need a filter. Note that yellow fog lights were in use when the only available headlights were incandescent lamps. If you place a filter over a white headlight, you get less transmitted light, and there goes your increased penetration down the drain. There are two possible explanations for yellow fog lights. One is that the first designers of such lights were mislead because they did not understand the limitations of Rayleigh's scattering law and did not know the size distribution of fog droplets. The other explanation is that someone deemed it desirable to make fog lights yellow as a way of signalling to other drivers that visibility is poor and thus caution is in order. Designers of headlights have known for a long time that there is no magic color that gives great penetration. I have an article from the Journal of Scientific Instruments published in October 1938 (Vol. XV, pp. 317-322). The article is by J. H. Nelson and is entitled "Optics of headlights". The penultimate section in this paper is on "fog lamps". Nelson notes that "there is almost complete agreement among designers of fog lamps, and this agreement is in most cases extended to the colour of the light to be used. Although there are still many lamps on the road using yellow light, it seems to be becoming recognized that there is no filter, which, when placed in front of a lamp, will improve the penetration power of that lamp."
- Fog lights are yellow and driving lights are white ... WRONG. There's more to it than that. When someone is thinking about installing fog lights, I start with questions: First of all, do you know what fog lights are? Secondly, what do you drive, where do you drive, what kinds of roads do you drive on? What kind of weather do you drive in? What do you want the fog lights for -- do you live in a real foggy area? Are they for pea soup fog or light fog, for snow, rain? Or just to look cool when you're cruising? Fog lights aren't necessarily amber lights, nor are amber lights always fog lights. There are amber driving lights, amber spotlights, and, in France, there are amber headlights. What makes a fog light is the light pattern, regardless of the type of lamp or color of the light. A real fog light -- one that will do you good when you're trying to see in the fog -- has a wide beam pattern (70 degrees to 120 degrees) with a sharp, flat cutoff on top. So beyond that, not all "fog lights" are created equal. There are lots of lights being marketed as fog lamps -- some very low priced, some hundreds of dollars a pair -- that, if I were driving in extreme weather, I would not turn on. They would make it harder to see. Fog lights, of course, are just one kind of auxiliary light. There are also driving lights, midbeams (passing lights) and spotlights for other purposes. And fog lights have many other functions besides fog, such as other types of bad weather and increasing side light for cornering. While fog lights are beneficial in fog or any other glare-producing conditions, they can also help you see better when you drive on a clear night. Mainly when you think of fog lights, you think of fog. Seeing through the fog?You can't see "through" fog. You see in foggy weather by lighting up the road under the fog, illuminating as little of the fog as possible to avoid producing glare. Fog is defined as a thick cloud of water droplets, 0.00039 to 0.00156 inches in diameter, suspended in the atmosphere at or near the earth's surface and reducing visibility to below half a mile. Your high beam headlights produce a wall of glare -- a whiteout -- from the light bouncing off these droplets of water. You're being blinded by the glare of your own lights reflected off the water vapor in front of you. Similar experiences occur in rain, snow, dust, etc. One solution would be to buy heated blowers like giant hair driers to dry the air in front of your car -- works great, costs a lot and uses a ton of energy. We may never deliver any of these, but you can start sending deposits in now (big ones). The amount of glare from the airborne moisture is affected by the relationship of angles between your line of sight and the angle of your car's lights. That's why you want a wide, flat beam from your fog lights. What you want your fog lamp to do is light up the road in front of you without lighting up the fog that's higher up, right in front of your eyes. Lenses and reflectorsIt helps to know something about the construction of the light -- specifically its lens and its reflector. The cuts in the lens, called fluting, shape the pattern by how they deflect the light. Ever knocked the lens out of your fog light? And noticed how it turned into a spot light? That's what it would be if it had a totally clear lens, with no fluting. Since the light passes through the lens, obviously the material of the lens would have an effect on how much light passes through. Lead crystal, being the clearest, allows the most light to pass through. Both ordinary glass and hardened glass are full of dirt and impurities that affect the passage of light. Plastic lenses block even more of the light. Most of the better lights are made with lead crystal lenses. Hardened glass doesn't break as easily, but is still as impure as ordinary glass. Plastic is basically useless for lenses because of impurities and because it gets scratched up. Breakage is, of course, an occasion for replacing lenses. And if fog lights are mounted in an air dam and you drive across the desert a lot, they get essentially sand blasted and all the little pits affect the flow of light and the light pattern. Even if you don't drive across the desert, your lenses will still be scuffed up by grit and you likely will want to replace them sooner or later, especially if you're using good quality lights. You also will care about the quality of the reflector, the shiny part that gathers the light from the bulb and reflects it out at precise angles through the lens. Good reflectors aren't chrome -- chrome appears to be shiny and reflective to the eye, but for reflecting light, it's not efficient! Some reflectors are silver plated. This is from the olden days. Prior to the invention of sealed beam headlights, American cars had separate bulbs, reflectors and lenses, and the reflectors were silver. Silver is not optimally reflective even when first applied. And through tarnishing, it loses 40 - 50% of its reflectivity after about 48 hours. These reflectors were supposed to be polished monthly. The preferred and most reflective material is an aluminized vapor coating. This is the neat stuff they use in microscopes and in mirrors for aiming lasers. Most of the higher quality lamps use this. Some lights also use a bulb shield, like a cup in front of the bulb. It blocks direct light from the bulb to the lens so that only light from the designed shape of the reflector passes through the lens. This reduces stray light above the cut-off. A word about bulbsHalogen bulbs have been around for about 30 years now. Most of the replaceable bulb type lamps utilize a halogen bulb. Some use a tungsten bulb -- this does not produce as much light per watt. Three common types of single-filament halogen type bulbs are H1, H2 and H3. The H1 puts out 29 lumens per watt (lm/w), the H2 is 33 lm/w and the H3 is 26 lm/w -- versus the 13 lm/w of a tungsten bulb. Any of these three could be found in a fog light. The bulbs don't interchange -- a lamp is built to take a certain bulb. The most common bulb wattage is 55 watts. A brighter option is a 100w bulb, which produces nearly twice as much light at the bulb filament, which wouild be a benefit in a larger lamp. In many of the smaller lamps, the reflector area is too small to efficiently gather the light and very little increase in light output occurs. Of course, the question of yellow, or amber, versus white needs to be addressed. I prefer white. Regardless of the fog lights' various types of construction, generally speaking amber or yellow fog lights become amber or yellow from coloring the lens or the reflector. This may reduce the light 15% to, in extreme cases, 50%. I once equipped a car with amber headlights, driving lights, spot lights and fog lights. I could light up reflective signs two miles away. But from not having the full spectrum of light, a lot of darker objects simply were not as visible. So I use white lights for their benefits the majority of the time. Some people prefer amber lights for more severe weather, and, obviously, for much less glare off of snow. But to me the disadvantages outweigh that benefits. Bigger lights are, all other things being equal, better. More reflector area reflects more light. Bigger, better lights do, however, cost more. Round lights are better than square ones with an equal area because the corners in a square lamp are sacrificing area. It isn't for the aerodynamics that rally cars have rows of big round lights across the front. There are various designs ranging from sealed beams (of which there are still some on the market) to the projector lights. Projector lights have the bulb sitting way in the back with an ellipsoid reflector behind it. A shield is used to perform the cutoff. The convex lens projects the light -- hence the term projector -- like a slide projector light. It's a sophisticated design whose advantages are that you can get the same amount of light with half the size of lamp, the beam is very wide and even, and the stray light above the cutoff is practically nil. The oldest and still most common types of separate bulb lamps use parabolic reflectors, which are something like a cross between a bowl and a funnel in shape. Another kind of lamp is called bi-focus or free-form. Instead of a parabolic reflector, it has a multi-planed reflector. This means the reflector itself has many different planes which focus the light before it hits the fluting in the lens, sort of "pre-aiming" the light from the bulb. Obviously, this begins to get fairly complex and much is done by the lighting manufacturers to research and develop materials and construction to make a light do what it's supposed to do. MountingAfter you have the right kind of fog light with the right pattern, next is how to mount it to get maximum benefit and this depends on what your goals are for your fog lights. For really severe weather, mounting the lights lower is better. But the lower the lights are mounted, the more vulnerable they are to impacts from stones and other various objects. The lower mountings also decrease how far forward the light will go (thanks to hills and the like). And the lower they're mounted, the more the shadowy effect from from rises and depressions in the road increases, which I find irritating. Mounting the lights low on the vehicle is useful only for pea-soup fog, snow squalls, etc. -- 20 mph driving conditions -- which I encounter very infrequently. So for the majority of the time, I feel I am better off with fog lights mounted on top of the bumper -- for greater distance and more visibility overall in less severe conditions. I'm still retaining the option of aiming them lower for extreme conditions (I can get out a wrench and point them at the ground 10 feet in front of the bumper when the weather is really bad). I also drive with my fog lights on in clear weather as cornering lights and for seeing animals and other things off on the side of the road waiting to attack my vehicle. Another important consideration when mounting fog lights is that they be mounted rigidly, so the beam stays pointed the way it's aimed, as opposed to dancing over tar strips on the road and the like. Dancing light beams will prove to be very irritating and, if they're dancing up and hitting those droplets of water, you're still going to have glare. AimingFog lights should be aimed straight ahead and level, or down a few degrees. For really severe weather, aim them down lower and give up the longer distance. In that situation, you don't need them to go 600 feet down the road, since you can only see 60 feet. A wide pattern with the light aimed straight ahead will give you some light off to the sides for cornering. So some people, whose prime concern is cornering light, will aim their fog lights so they spread apart off to the sides, pointed away from each other, to increase the off-the-road light. This will increase the amount of side light from the outside part of each light. But it will decrease the light in front of the car, and thus the distance they go straight down the road in front of you. Here's a better idea. On some of the rally cars I've prepared, we aimed the fog lights so the light patterns would cross each other (the left light would light up the right side, and the right light, the left side). This gives the same amount of light off to each side, but in front of the vehicle, it's brighter where the beams overlap. Keep 'em cleanNo matter what the color or pattern of your fog lights, keep them clean. Just a few days' worth of road dirt can cut the light be up to 50%. In winter, mud and snow can reduce light up to 90%! But now you know the basics -- what fog is, the types of fog lamps available, how to mount and aim fog lights for your intended purpose. So, how do you chose a fog light?Buy them all and compare them, or consult an expert. You could read everything there is about a light, but that won't tell you everything. For example, you can't compare reflective ranges from different manufacturers, because they may not all use the same reflector. Ultimately, you can't know how a light works until you put it in a vehicle and drive down the road with it -- or talk to someone who has.
- http://www.ehs.wsu.edu/Factsheets/Winterdriving.htm