Driver-Assist Features & Their Limits
Many vehicles now brake on their own, nudge you back into your lane and keep a set distance from the car ahead. These features prevent crashes, but they aren’t self-driving. Drivers who trust them too much stop paying attention, and that causes crashes.
- All drivers
- Fleet drivers
Photo: dashboard display showing adaptive cruise control and lane keeping active, driver’s hands on the wheel
Common features
| Feature | What it does | Limits |
|---|---|---|
| Automatic emergency braking | Brakes if a crash is about to happen | May not stop in time at higher speeds; may miss pedestrians, cyclists, stopped vehicles or debris |
| Lane departure warning / lane keeping | Warns or steers when drifting out of a lane | Needs clear lane lines; struggles in rain, snow, construction zones and sharp curves |
| Adaptive cruise control | Keeps a set distance from the car ahead | May not react to stopped cars, merging traffic or motorcycles |
| Blind spot monitoring | Warns of vehicles beside you | Doesn’t replace a head check; fast cars may not show |
| Backup camera and rear braking | Shows or brakes for objects behind | Can’t see everything; dirty lenses blind it |
No car you can buy drives itself
Systems sold to drivers today, even ones with names suggesting autopilot, require you to watch the road and be ready to take over at any moment. You’re responsible for driving.
Using them safely
- Read the owner’s manual to learn what your systems do and don’t do.
- Keep your eyes on the road and hands on the wheel.
- Keep cameras and sensors clean of dirt, snow and ice.
- Turn off lane keeping and adaptive cruise in work zones, heavy rain or snow if they behave unpredictably.
- Get repairs and recalibration after windshield replacement or bumper damage, since sensors can be knocked out of alignment.
Don’t use driver assist as permission to be distracted. Checking your phone because “the car is driving” is one of the most dangerous habits on the road. See Distracted Driving.
Standards & references
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