If you haven't bought a car for a while, some of the more new-fangled technology and "autonomous" assist features may be new to you. These are features that help drivers do a better job of driving, without actually doing the driving.
Lane Keep Assist (LKA) may go by a few different names (Lane Trace Assist, for example), and some automakers have copyrighted names for systems that include this feature (like Nissan's "ProPilot Assist"). But the goal is pretty self evident: To keep a driver in his lane.
Some vehicles will only offer an audible warning, but most automakers who are adding this feature offer some kind of actual physical intervention. It could be the application of brakes on the left side if you get too close to the left lane marker. Or, more aggressively, some automakers apply steering assist.
How does the feature work? Through the use of cameras. It could just be the front camera, but a lot of vehicles now have cameras on the side mirrors -- not only for this function but also for around-view back-up cameras.
If you turn on your blinker to change lanes, LKA is deactivated because the car knows your intention to cross the lane marker.
Where systems like this often fail, however, is in construction zones where new lane lines are painted over old lane lines. I've had several instances of LKA trying to nudge me in the wrong lane. So, while systems like this are helpful for a momentary lack of concentration (like your mom sitting in the passenger seat and point at something in a different direction), they are not a substitute for actual driving.
I have to admit, the first time I was in a vehicle with the steer assist, it freaked me out. It was kind of like a hacker was taking over and pushing me in a direction I couldn't control -- but most systems are more mellow. You'll feel a nudge of the wheel if the car doesn't agree with the line you're taking in the lane, but you can easily override the nudge.
However, if you've never experienced this, it's still a creepy feeling.
Luckily, if you don't want the assist, there are usually buttons to turn this feature on and off. In some cases you may have to page through system settings on the info screen to turn it off, but I haven't found a vehicle yet where "off" isn't an option.
As an FYI, a really great resource for safety features on vehicles is “My Car Does What?” It’ll show you images and icons as well as describe what the feature does.
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