Driver EducationSection VI

• Day 3 - Traction Concerns

DE SOL 13

• The student will identify changes in the environment that affect visibility and traction and demonstrate an understanding of appropriate driver reaction to these risksd. Vehicle stability and traction control systems

Objectives

• Understand and properly use vehicular protection features and roadway technologies that reduce injury severity and increase collision survival

• Recognize vehicular imbalance and choose appropriate countermeaures to prevent loss of vehicle control

Study for your Quiz

• 10 Minutes to study

• When you finish the quiz do your Bell Ringer

Day 3 – Traction Concerns

• Bell Ringer –– 2paragraphs – Can do 1 paragraph for each question

• Name at least 3 situations when a car may need to stop quickly. List factors that may make this difficult.

Causes ofCauses of Traction LossTraction LossDOE PP > Module 8

Condition of the VehicleCondition of the VehicleBrakes unevenly adjusted

Brakes pulling in one direction or the other can cause

a skid--as can wheels out of alignment when brakes

are applied

Tires with unevenly worn tread

- The size of the front and rear tires do not match

- The tread depth or tire type of the front and rear tires are

different

Different tire pressure on opposite sides of the vehicle

has a similar effect to uneven brake adjustment since one tire

will drag more than others

Handout

Causes ofCauses of Traction LossTraction Loss DOE PP > Module 8

Driver ActionsDriver Actions

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

Handout

Causes ofCauses of Traction LossTraction Loss DOE PP > Module 8

Driver ActionsDriver Actions

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

Handout

• Sudden shifts of vehicle weight causes traction loss - Left, Right, Forward, or Backward

• Simultaneous steering, braking and/or acceleration creates sudden shifts in vehicle balance

• Traction loss compounds crash consequences

Traction Loss ConsiderationsTraction Loss Considerations DOE PP > Module 8 Handout

• Sudden shifts of vehicle weight causes traction loss - Left, Right, Forward, or Backward

• Simultaneous steering, braking and/or acceleration creates sudden shifts in vehicle balance

• Traction loss compounds crash consequences

Traction Loss ConsiderationsTraction Loss Considerations DOE PP > Module 8 Handout

Weight Moves to the Front of the Car Causing Weight Moves to the Front of the Car Causing

– a noticeable drop of the hood

– a noticeable rise of the rear deck

– forward movement of driver and passengers

When When BrakesBrakes are Applied Too Hard or Quickly are Applied Too Hard or Quickly

Direction of Travel

Force or Weight Movement

Rear Rear LIFTSLIFTS

Front DROPSFront DROPS

Traction Loss ConsiderationsTraction Loss Considerations DOE PP > Module 8 Handout

Weight Moves to the Rear of the Car CausingWeight Moves to the Rear of the Car Causing

– a noticeable rise of the hood

– a noticeable drop of the rear deck

– rearward movement of driver and passengers

When When AccelerationAcceleration is Applied Too Hard or Quickly is Applied Too Hard or Quickly

Direction of Travel

Front LIFTSFront LIFTS

Force or Weight Movement

Rear Rear DROPSDROPS

Traction Loss ConsiderationsTraction Loss Considerations DOE PP > Module 8 Handout

Weight Moves to the Opposite Side of the CarWeight Moves to the Opposite Side of the Car

Weight Movement Causes: 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

When When SteeringSteering is Applied Too Hard or Quickly is Applied Too Hard or Quickly

Force or Weight Movement Front DROPSFront DROPS

Rear Rear LIFTSLIFTSDirection of TravelDirection of Travel

Traction Loss ConsiderationsTraction Loss Considerations DOE PP > Module 8 Handout

If A Vehicle Keeps Moving Straight Ahead in Spite of Steering Efforts To the Contrary, It Means Front Traction Has Been Lost

The Technical Term is Called “Under steer”

Actual Path Actual Path of Travelof Travel

Intended Path Intended Path of Travelof Travel

front tires front tires SLIDESLIDE

rear tires rear tires PUSHPUSH

The Driver Will First Visually Identify Unusual Forward Sliding Movement Caused by the Vehicle’s Weight Pushing the Front Wheels Straight Ahead Regardless of Any Steering Input

Traction Loss to Front TiresTraction Loss to Front Tires DOE PP > Module 8 Handout

Targeted Path of TravelTargeted Path of Travel

Lift Eyes to Lift Eyes to TargetedTargeted Path of TravelPath of Travel

Intended Path of TravelIntended Path of TravelActual Path Actual Path

of Travelof Travel• Direct Vision to Targeted Path of TravelDirect Vision to Targeted Path of Travel

• Activate ABS, if Vehicle is EquippedActivate ABS, if Vehicle is Equipped– Ease off Conventional Brake System– Reestablish Rolling Traction

• Ease off Steering InputsEase off Steering Inputs– Abrupt Steering Can Create Traction Loss– Allows Tire Tread to Point Toward Path of Travel

• Jab/Stab Brake to Move Weight Forward if ABS is not Available Jab/Stab Brake to Move Weight Forward if ABS is not Available

(ABS performs this function automatically)(ABS performs this function automatically)

To Correct Front Traction Loss To Correct Front Traction Loss DOE PP > Module 8 Handout

• Identified by driver when front of vehicle moves to the left or Identified by driver when front of vehicle moves to the left or right of travel path without steering input in that directionright of travel path without steering input in that direction

• Technical term is Technical term is “Over steer”“Over steer”

Intended Path of TravelIntended Path of Travel Actual Path Actual Path of Travelof Travel

• Vehicle’s Weight Tends to Push Rear Vehicle’s Weight Tends to Push Rear Wheels Left or Right Without Steering InputWheels Left or Right Without Steering Input

• Vehicle Begins To YawVehicle Begins To Yaw

front tires front tires ROLLROLL

rear tires rear tires SLIDESLIDE

Traction Loss to Rear TiresTraction Loss to Rear Tires DOE PP > Module 8 Handout

• Direct Vision to Targeted Path of TravelDirect Vision to Targeted Path of Travel

On Targeted Path

On Targeted Path

Off Targeted Off Targeted PathPath

• Steer Toward Targeted Path of TravelSteer Toward Targeted Path of Travel

• Adjust Steering Input as Needed to Maintain Targeted Path of Travel Adjust Steering Input as Needed to Maintain Targeted Path of Travel

• Apply Light Progressive Acceleration (2 mph is goal) to Move the Apply Light Progressive Acceleration (2 mph is goal) to Move the Weight to the Rear. (The Traction Control System will adjust the Weight to the Rear. (The Traction Control System will adjust the speed and brakes automatically when activated)speed and brakes automatically when activated)

• Activate Traction Control Activate Traction Control System, if Equipped:System, if Equipped:

– Ease off brake or accelerator

– Reestablish rolling traction Intended Intended

Path of Path of TravelTravel

Rear Tire MovementRear Tire Movement

To Correct Rear Traction Loss To Correct Rear Traction Loss DOE PP > Module 8 Handout

• Do not panic and steer too abruptlyDo not panic and steer too abruptly

• Ease off accelerator Ease off accelerator

• DO NOT BRAKEDO NOT BRAKE

• Get both wheels off the pavementGet both wheels off the pavement

• Steer the vehicle parallel to the roadwaySteer the vehicle parallel to the roadway

• If clear, ease back on to the roadway one wheel at If clear, ease back on to the roadway one wheel at a timea time

• Limit steering inputs to less than 1/8 of a turn of Limit steering inputs to less than 1/8 of a turn of the wheel the wheel

• Use even less input when the edge of road is highUse even less input when the edge of road is high

• Target the center of the adjacent lane to avoid a Target the center of the adjacent lane to avoid a “Slingshot” maneuver into oncoming traffic “Slingshot” maneuver into oncoming traffic

Off Road RecoveryOff Road Recovery DOE PP > Module 8 Handout

Electronic Stability ProtectionVideo Clip (Over and Under Steer)

Classwork #6

• Read Pages 257 – 259– “Natural Laws and Steering and Braking

– Answer Lesson 2 Review Question 1 - 4

Video – “In Control”31 Minutes

RememberTest Tomorrow