I keep referring to it as LKA, but it is not, it is "LaneSense" and the name itself implies the limits of the system (no "keeping")
Page 408 of the 2017 Owners Manual:
LaneSense Operation
The LaneSense system is operational at speeds above 37 mph (60 km/h) and below 112 mph (180 km/h). It uses a forward looking camera to detect lane markings and measure vehicle position within the lane boundaries.
When both lane markings are detected and the driver unintentionally drifts out of the lane (no turn signal applied), the LaneSense system provides a haptic warning in the form of torque applied to the steering wheel to prompt the driver to remain within the lane boundaries.
The LaneSense system will also provide a visual warning through the instrument cluster display to prompt the driver to remain within the lane boundaries.
The driver may manually override the haptic warning by applying torque into the steering wheel at any time.
When only a single lane marking is detected and the driver unintentionally drifts across that lane marking (no turn signal applied), the LaneSense system provides a visual warning through the instrument cluster display to prompt the driver to remain within the lane. When only a single lane marking is detected, a haptic (torque) warning will not be provided.
NOTE: When operating conditions have been met, the LaneSense system will monitor if the driver’s hands are on the steering wheel and provides an audible and visual warning to the driver when the driver’s hands are not detected on the steering wheel. The system will cancel if the driver does not return their hands to the wheel.
Page 232 of the 2017 Users Manual:
LaneSense Indicator Light
This light will appear either white, yellow, or green in the instrument cluster.Depending on which color it appears, it could mean one of the following:
• White — The LaneSense Indicator Light turns on and is white when the LaneSense system is on, and none, or only the left, or right, lane marking has been detected.
• Yellow — The LaneSense Indicator Light turns yellow when the LaneSense system is on, and has detected a lane drift situation. It will begin to flash when the system sense the lane has been approached and the vehicle is in a lane departure situation.
• Green — The LaneSense Indicator Light turns green when the LaneSense system is on, both lane markings have been detected
So the Pacifica will, within limits, nudge you back from the line. It will make no further effort to keep you in the lane unless you drift over to one side again. So "ping pong" scenarios can develop.
As noted above, the more "assists" we get while driving, the more likely it is our attention will wander or be easily distracted ("what's the title of the song on the radio?")
If you saw the video of the Uber incident that killed the woman with a bike, the backup dirver was looking in their lap.
When I worked in the railroad industry many years ago, one of the challenges was devising what are called "dead man" systems to detect when a locomotive engineer is not paying attention, possibly due to a medical incident. Unlike some of the systems used in subway systems, which require pressure on a throttle handle and which the operator can rest at station stops, these systems were designed to allow some freedom since the train can go hours without a stop -- requiring a touch or other action at a time interval after it detected a "hands off" situation. The locomotive engineers were often just as ingenious in finding ways to get around the deadman systerm -- investigations find that root cause of many accidents in all industries are users working very hard to defeat the safety systems. Read on another thread how someone figured out how to power open the sliding doors while still moving.
Until we get to true self-driving cars, we are going to be in this dangerous zone where driver assist systems lead to attention fatigue for the average driver.