System Description

1. The lane-keeping assist system uses an image of the road from the lane-recognition camera sensor to detect the lane markers for the lane that the vehicle is in. If the system detects that the vehicle is about to move out of its lane, it uses the warning buzzer, multi-information display and steering assistance to warn the driver.
   Fig 1: Identifying Lane Keeping Assist Display

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   TEXT IN ILLUSTRATION
   
   

   *1	White lines	*2	Steering wheel
   *3	Radar cruise display	*4	Radar cruise set vehicle speed
   *5	LKA Indicator	-	-

   • White lines
     • The white line indicate the condition of the lane keeping assist system.
       1. Lines are not displayed: Lane keeping assist system is off.
       2. Thin lines are displayed: Lane keeping assist system is off.
       3. Thick lines are displayed: Lane keeping assist system is operating.
   • Steering wheel
     • When the steering wheel is displayed, this indicates that the lane keeping assist function is operating.
   • Radar cruise display
     • Indicates operation conditions for radar cruise
   • Radar cruise set vehicle speed
     • Indicates the set vehicle speed when the radar cruise is activated

   However, in the following conditions, the lane-keeping assist system may not function normally.

   • Vehicle is near toll booths or similar areas
   • Road has no lane marker
   • Lane marker are cracked
   • Road has yellow lines
   • There is a shadow on either of the lane marker
   • As a result of reflections, road surface is bright
   • Road with reflective surface similar to concrete road
   • Area where brightness changes suddenly, such as entrances and exits of tunnels or similar area
   • Bright light directed at sensor
   • Incline of road varies, winding road or other type of road where road surface is irregular
   • Bad weather
   • Frozen or snowy roads
   • Road surface with water or other liquid

1. Lane departure warning function:

   The lane departure warning function operates when the lane-keeping assist switch is on, the vehicle speed is 48 km/h (30 mph) or more, and lane markers on the road surface are detected. With the lane departure warning function operating, if the vehicle is about to move out of the lane and this is detected by the driving support ECU, the ECU uses the warning buzzer and the multi-information display to warn the driver. Also, the ECU uses the electronic power steering system's motor to apply steering force and give suggestions to the driver for lane departure avoidance.

   HINT: 

   This function only provides suggestions for lane departure avoidance. This function does not automatically move the vehicle within a lane.

   Lane Departure Warning Function Operation Stop Condition	Restart Condition
   When vehicle speed is less than 48 km/h (30 mph)	When vehicle speed is 48 km/h (30 mph)
   When turn signal light switch is operated	When turn signal light switch is turned off
   When steering force above a specified amount is applied	When steering force above a specified amount is not applied
   When windshield wiper switch is set to Lo or Hi	When windshield wiper switch is turned off
   When lane recognition camera sensor cannot detect lane marker	When lane recognition camera sensor can detect lane marker
   While brake pedal operation is being detected	After brake pedal operation is completed
   After lane departure warning has been issued	When the vehicle is back to its lane, or a few seconds have passed since warning was executed

2. Lane-keeping assist function:

   The lane-keeping assist function operates when the lane-keeping assist switch is ON, the vehicle speed is approximately 72 to 180 km/h (45 to 112 mph) and the dynamic radar cruise control system is ON. With the lane-keeping assist function operating, steering assistance is provided for the driver according to the driving conditions so that the vehicle stays near the midpoint of a lane. When the vehicle cannot be maintained within a lane and this is detected by the driving support ECU, the ECU uses the warning buzzer and the multi-information display to warn the driver. During the lane-keeping assist function operation, if any of the following conditions occurs, the lane-keeping assist function will stop operating. If the condition is no longer detected, the lane-keeping assist function will automatically start operating again.

   Lane-keeping Assist Function Operation Stop Condition	Restart Condition
   When lane recognition camera sensor cannot detect lane marker	When lane recognition camera sensor can detect lane marker
   When vehicle speed is not within 72 to 180 km/h (45 to 112 mph)	When vehicle speed is within 72 to 180 km/h (45 to 112 mph)
   When turn signal light switch is operated	When turn signal light switch is turned off
   When windshield wiper switch is set to Lo or Hi	When windshield wiper switch is turned off
   When steering force above a specified amount is applied	When steering force above specified amount is not detected
   When steering force above a specified amount does not occur*	When steering operation is detected
   When changing lanes	When driving within a lane is confirmed

   HINT: 

   *: This refers to situations where the vehicle is driven for 15 seconds or more on a lane that is straight; or 5 seconds or more on a curved road (curve radius 1000 m (3281 ft.) or less).

During the lane-keeping assist function operation, if any of the following conditions is detected, the lane-keeping assist function will stop operating.

• When dynamic radar cruise control system is canceled*
• When lane-keeping assist switch is turned off
• When object recognition camera sensor's interior temperature is 70°C (158°F) or more
• When lane-keeping assist system is malfunctioning

  HINT: 

  *: During the lane-keeping assist function operation, if the dynamic radar cruise control system is canceled, the lane-keeping assist system will change from the lane-keeping assist function to the lane departure warning function.

The LKA indicator light is built into the combination meter. It informs the driver of the operational condition or malfunctions of the lane keeping assist system.