1. Module 9: Adverse Driving Conditions Topics 1-3 Visibility, Rain, Snow/Ice Roadway Design Traction Loss

2. Accident Facts ○ Nearly 1 million crashes occur every year due to reduced traction under adverse driving conditions. [NHTSA] ○ These are caused by drivers who fail to adjust techniques to account for adverse conditions. [NHTSA]

3. Skids Why Skids Happen? ○ Skids happen whenever tires lose their grip on the road ○ Whenever the force applied to the tire exceeds the tire’s traction ○ Tires lose their grip for 1 of 4 reasons: ○ Overbraking ○ Oversteering ○ Overacceleration ○ Driving too fast ○ Your goal must be to keep the tires below the threshold of skidding ○ Even the best skid-control skills won’t prevent a collision if the available room is less than the space required to stop or escape

4. Why Skids Happen Adverse Conditions ○ Overbraking: ○ Braking too hard & locking up the wheels; ○ Braking when the road is slippery ○ Oversteering: ○ Turning the wheels more sharply than the vehicle can turn ○ Overacceleration: ○ Supplying too much power to the drive wheels, causing them to spin ○ Driving too fast: ○ Approaching hazards so quickly that there is no time to recognize & react properly

5. Skids on Dry Surfaces ○ Most skids, spins, & slides happen on wet, icy, or snow-packed surfaces ○ Loss of control can also happen on dry surfaces when you combine high speeds with quick changes in direction

6. Braking Skid ○ How does it happen? ○ Apply brakes too quickly or too hard. ○ Consequences? ○ Car might spin or slide forward or sideways. ○ Actions ○ Take your foot off the gas and steer. ○ When wheels start turning again and moving forward, steering control will return.

7. Power Skid ○ How does it happen? ○ Gas is pressed suddenly, too hard. ○ Consequences? ○ FWD vehicle: plows ahead ○ RWD vehicle: back end will slide ○ Actions ○ Ease up on gas ○ Steer to straighten

8. Cornering Skid ○ How does it happen? ○ Turn too fast, poor tires or slippery road in a curve. ○ Consequences? ○ Steering control is lost. ○ Rear wheels skid away from turn, car goes straight. ○ Not straight on the roadway. ○ Actions ○ Take your foot off the gas. ○ Steer to straighten the vehicle.

9. Blowout Skid ○ How does it happen? ○ Punctured, overinflated, or worn tire; overloaded vehicle. ○ Consequences? ○ Strong pull towards side with blowout. ○ Steering severely compromised. ○ Actions ○ Do not brake. ○ Make firm, steady steering corrections. ○ Slow down gradually, pull off road

10. Preventing Skids ○ The key to maintaining traction at all times is to recognize when a skid is possible and take action to prevent one from occurring.

11. Off-Road Recovery (Loss of traction in 1 or more tires) ○ If your car goes off the roadway… ○ Stay calm. ○ Do not immediately jerk the wheel back the other way; most accidents by teen drivers are from overcorrecting. ○ Keep a firm grip ○ Resist the tendency of the vehicle to pull toward the shoulder if it is soft. ○ If your path of travel is clear ○ Remain calm and do the following: ○ Ease off the accelerator, and slow down gradually. ○ If possible, avoid braking.

12. Off Road Recovery ○ If you must return to the road quickly… ○ Do the following: Align your wheels 12 inches away from the edge of the pavement. Remove your foot from the accelerator and stay off the brakes. Turn the steering wheel quickly about 1/8th turn toward the road. As the outer wheel meets the edge of the pavement, counter-steer about a 1/4 turn. Make steering corrections to center or straighten steering. Continue to look and steer where you want to go.

13. Strong Winds ○ Create a problem called buffeting ○ Conditions occur on bridges and overpasses ○ Through mountain passes and ravines ○ When being passed by large trucks ○ These winds gust and blasts can cause total loss of vehicle control

14. Center of Gravity and Wind ○ All vehicles are affected by high winds ○ Higher center of gravity = more affected ○ Tractor Trailer and Wind ○ https://www.youtube.com/watch?v=WUOCD2hs NLg https://www.youtube.com/watch?v=WUOCD2hs NLg ○ https://www.youtube.com/watch?v=EibCuXvkR Sw https://www.youtube.com/watch?v=EibCuXvkR Sw

15. Wet Leaves Characteristics ○ Reduce traction because they come between your tires and the road. ○ Are slippery, just like ice

16. Night Driving ○ 60% of fatal accidents occur at night. ○ Night driving factors: ○ Reduced visibility ○ Ability of the eyes to adjust to glare

17. Visibility & Night Driving ○ Headlights only allow you to see so far in advance, and so far off to the side. ○ Therefore, can’t see as much stuff in advance ○ Lack of contrast impairs distance judgment. ○ Glare and glare recovery time ○ Older you get, longer it takes

18. Night Driving Strategies ○ Reduce speed, increase following distance. ○ Use high-beam headlights if necessary, when safe and legal ○ Low-beams when following a vehicle

19. If Oncoming Lights Are Bothering You ○ Don’t look directly at the lights ○ Use the white line on the right edge of the road to guide you until they pass. ○ Don’t high-beam someone because they’re high- beaming you. ○ Then, neither of you can see.

20. Glare Other vehicles The sun Icy roads Snow-covered landscape

21. Sources of Glare ○ Vehicle headlights: oncoming, behind you, and behind you into your mirrors ○ Dirty windshield ○ Snow-covered landscape ○ Facing the sun (dawn/dusk) ○ Flashing advertisement signs ○ Failure to dim your own headlights in fog

22. Managing Glare ○ Look to the right edge of the roadway ○ Keep all windows and lights clean. ○ Use sun visors when necessary. ○ Adjust mirrors to BGE settings (reduces glare). ○ Sit high in the seat. ○ Wear sunglasses (even in Winter). ○ Illegal to wear them at night

23. Fog ○ Characteristics ○ Ground-level cloud, made up of many tiny floating water droplets ○ Low visibility ○ Difficulty judging speed and distance ○ Short reaction time ○ We pavement – can become icy in cold weather

24. Fog ○ In fog, make sure headlights are on low-beam. ○ High-beam headlights reflect back off of the fog ○ If your car has fog lights, use them. ○ Shine under the fog Video: Driving Safely in Fog https://www.youtube.com/watch?v=8weiu4mD2nQ

25. Fog

26. Driving Into Fog http://www.youtube.com/watch?v=ckPrB9NMyLI Start at 2:00

27. If Heavy Fog/Rain and You Can’t See ○ Carefully pull off to the shoulder of the road or into a parking lot. ○ If you can, pull off to the shoulder under a bridge. ○ Turn on your emergency flashers so other drivers on the road can see you. ○ Wait until it is safer for you to proceed.

28. Rain/Flooding Characteristics ○ Traction loss ○ Lower visibility ○ Hydroplaning and skids

29. Friction Factors: Rain ○ When the road is wet, rain gets between tires and the road. ○ At 55mph, a car can lose contact with the road with as little as 1/12 inch of water. ○ The first 30 minutes of rainfall are the most dangerous, as rain mixes with oil from vehicles already on the road.

30. Hydroplaning ○ During a heavy downpour, water on the pavement can cause your vehicle to hydroplane ○ Your front wheels ride on a wedge of pressurized water & rise off the road surface https://www.youtube.com/watch? v=TdwuftIUwYY

31. Hydroplaning ○ Wet conditions, water on the road, excessive speed, under-inflated tires and low tire tread can cause your tires to lose contact with the roadway and lose traction. ○ Question: What can you do to help prevent hydroplaning?

32. Hydroplaning When tires lose traction with the road and begin skimming along on a thin surface of water. http://www.youtube.com/watch?v=spaOeDD3rgo

33. Hydroplaning Since your wheels no longer contact the road, you will experience a partial or total loss of steering control The only solution is to reduce speed: Gently reduce pressure on the accelerator to bring the speed down

34. Heavy Rain ○ Flash Flood: A lot of rain in a short time ○ Ground can’t hold all the water; drains can’t drain road surfaces quickly enough ○ NOT a “regular” flood ○ After a couple hours, the water is no longer high.

35. Flooded areas ○ Avoid driving through standing water ○ Takes ankle to knee-high water to stall out your car ○ Vehicles that are lower to the ground = less water ○ If you can’t see the center lines, you shouldn’t be driving on the road.

36. Low Water Crossings ○ Nearly 50% of flash flood fatalities are vehicle related ○ Search for flood prone areas ○ Highway dips ○ Bridges ○ Low areas ○ Largest and heaviest of vehicles will float ○ Six inches of water may cause loss of control ○ Two feet of water carries most cars ○ Heed all flood watches and warnings ○ Never enter deep water that is moving. Take another route

37. Drying Brakes Wet brakes don’t work as well as dry ones. After driving through a deep puddle or heavy rain, dry your brakes. Apply brakes lightly If brakes are wet: vehicle doesn’t stop as usual vehicle pulls to one side Dry by applying slight pressure to brake for ~ 2sec. Friction will dry your brakes.

38. Snow and Ice Characteristics ○ Low Traction ○ Not always visible ○ Reduced visibility due to active snow, snowbanks etc. ○ Shoulder on roadway is reduced

39. Ice ○ Expect icy conditions any time the outside air temperature reaches 40 degrees F or lower. ○ Although water freezes at 32 degrees F, road surface can freeze when the air temperature drops to 40 degrees 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. ○ Video: How to Drive on Ice & Snow https://www.youtube.com/watch?v=UA7nclek K6U

40. Video Clip: Winter 2-Lane Driving

41. White Ice Adverse Conditions ○ White ice is usually visible to the eye ○ White ice is usually created in 1 of 2 ways: ○ Compacted snowfall that has slightly melted & then frozen; ○ Rainfall that freezes

42. Black Ice ○ Black ice, clear water that has frozen on black pavement, usually forms below overpasses, on bridges, in areas that are surrounded by landscape or on a source of water running across pavement. ○ Black ice commonly occurs in low, shaded areas and/or when the road surface starts to freeze at night. ○ You usually cannot see or feel this ice until the vehicle is already on it. ○ You may not expect a patch of ice because you've been driving on dry, clear pavement. ○ It maybe an area where melting snow or a roadside spring caused water to run onto the road and freeze. ○ If you are not aware that the water has frozen, you could lose control and the vehicle could skid. https://www.youtube.com/watch?v=0JWJeJcQnwIhttps://www.youtube.com/watch?v=0JWJeJcQnwI (2:37)

43. Vehicle Control During Winter ○ Accelerating, turning, & passing present dangers during winter: ○ Accelerate slowly to avoid loss of traction & subsequent loss of control; ○ Turn slowly with caution to avoid sliding into a stationary object or the path of an oncoming vehicle; ○ Pass with care because passing lanes are not maintained as well; ○ Avoid sudden or swift movements ○ Triple your following distance so there’s plenty of room to see & maneuver

44. Driving in Snow/Ice http://www.youtube.com/watch?v=-Sw19pJscCk

45. Managing Snow/Ice ○ In addition to basic adverse conditions driving: ○ Avoid sudden braking and jerky steering ○ If you need to slow down going downhill, use your lower gears (2 or 1, or L) to slow your car without having to brake.

46. Bridges in Snow/Ice ○ Bridges freeze before the road surface freezes ○ Ground holds in heat ○ Bridges are exposed to cold, wind underneath and on top, lose heat from both sides

47. 4WD and AWD in Snow/Ice ○ If two wheels lose traction or are stuck, the other 2 can still get traction and move the vehicle. ○ 4WD/AWD do not provide extra braking capability. ○ 4WD/AWD do not provide improved traction on ice.

48. Winter Driving & Tire Pressure ○ For every 10 degrees drop in outdoor temperature, the air pressure inside your tire drops 1-2 psi ○ Regularly check tire pressure for proper inflation ○ Never reduce air pressure in an attempt to increase traction on snow or ice – your tires could be seriously damaged. ○ If you get stuck, a spinning tire could explode when your speedometer reads over 35 mph

49. Winter Driving Emergency Kit Heavy Clothes and Blankets Traction Material (sand and kitty litter) Tire Chains Small Shovel First Aid Kit Flashlight Jumper Cables Bright cloth to use as an identifying flag

50. Tailgating ○ Your exit options are reduced when you tailgate ○ A skid or a slide can result because you are unable to adjust speed, space, or direction in a controlled manner

51. Smart Thinking ○ Think ahead about your driving: ○ Know the adjustments needed for current weather conditions ○ Be knowledgeable about your tires: ○ Make sure your vehicle is equipped with the correct performance tires; ○ When in doubt ask a tire dealer for information

52. Preventing Reduced Visibility ○ Have clean windshield, headlights, etc. ○ Replace wiper blades when necessary and always have washer fluid

53. Planning Ahead Drive smoothly: Avoid abrupt braking, accelerating, or turning Plan your braking: Slow down prior to a curve or a hill; This will reduce your braking distance while increasing traction

54. Driving in Adverse Conditions Drive more slowly: As your speed decreases, the tire footprint increases, providing better traction Maintain a safe distance: 2X or 3X the normal space cushion Be extra alert at intersections Check for other vehicles that are not adjusting for current conditions Adverse Conditions

55. Controlling Consequences ○ If you must hit something… ○ Avoid head-on collisions ○ Drive off the road rather than skid off the road ○ Hit something soft rather than something hard ○ Hit something going your way rather than something that’s not moving ○ Hit a non-moving object at an angle rather than straight-on ○ Steer to avoid oncoming traffic

56. ROAD SURFACE AND TRACTION Traction: Traction is the adhesion, friction or grip between the tires and the road surface. Question: How does traction vary and what can affect it? Causes of traction loss (skidding) can be divided into three categories ▪Condition of the road ▪The vehicle ▪Actions of the driver

57. TYPES OF TRACTION Three types of traction influence the control/or movement of a motor vehicle. 1.Static: stationary car with brakes set, greatest resistance to movement. 2.Rolling (dynamic): more traction than with a sliding wheel Driver must keep wheels rolling and not sliding: don’t lock brakes 3.Sliding: loss of traction

58. CAUSES OF TRACTION LOSS Driver Actions that may cause TRACTION LOSS: ✓ Sudden steering actions on a slippery surface, or abrupt or sudden changes in vehicle speed ✓ Panic stop or applying the brakes too hard on a hill, curve or slippery surface ✓ Suddenly engaging the clutch on a slippery surface Most driver-induced skids are caused by: ✓ excessive speed ✓ coupled with excessive steering input ✓ or improper braking when turning Loss of traction also occurs with these driver’s actions at normal speeds on ice/snow or on roadways covered by sand, gravel, or water

59. TRACTION LOSS CONSIDERATIONS When the BRAKES are applied TOO HARD or QUICKLY Weight Moves to the Front of the Car Causing Forward PITCH ▪a noticeable drop of the hood ▪a noticeable rise of the rear deck ▪forward movement of driver and passengers

60. TRACTION LOSS CONSIDERATIONS When ACCELERATION is applied TOO HARD or QUICKLY Weight Moves to the Rear of the Car Causing Backward Pitch ▪a noticeable rise of the hood ▪a noticeable drop of the rear deck ▪rearward movement of driver and passengers

61. TRACTION LOSS CONSIDERATIONS When Steering is Applied Too Hard or Quickly ✓ Weight Moves to the Opposite Side of the Car causing Roll to the left or right ✓ Weight Movement Causes: ▪a noticeable drop and tilt of the hood ▪a noticeable rise and tilt of the rear deck ▪driver and passenger movement towards the car’s corner

62. BRAKING AND ACCELERATING SKIDS

63. TYPES OF SKIDS

64. FRONT WHEEL LOSS OF TRACTION TERMED “UNDERSTEER” Vehicle moving straight ahead in spite if steering input May first be identified visually Tires tend to roll under Rear wheels tend to push front straight ahead CORRECTIONS Direct vision to path of travel Ease off steering Re-establish rolling traction

65. REAR WHEEL LOSS OF TRACTION TERMED “OVERSTEER” Rear wheels try to assume front position Generated by slick surface, speed, braking or sudden steering input Identified visually as front of vehicle moves left or right of travel path without steering input in that direction CORRECTIONS Direct vision to path of travel Ease of brake or accelerator Steer back toward path of travel Direct vision to travel lane not road shoulder Light progressive acceleration may be needed to return rear tire traction

66. Oversteer and Understeer https://www.youtube.com/watch?v=qoi75nSi scE&list=PLD6Mwp7MQHhGXHuWTAry4aJbJ5 JDwL9Po https://www.youtube.com/watch?v=qoi75nSi scE&list=PLD6Mwp7MQHhGXHuWTAry4aJbJ5 JDwL9Po