Key takeaways
- NHTSA, the US vehicle safety regulator, says that even the highest level of automation available to consumers “requires the full engagement and undivided attention of drivers.”
- Driver-assistance features either warn you of a danger or act to avoid it. Automatic emergency braking is an example of acting.
- Automakers use different names for the same features, so check your owner’s manual for what your car actually does.
- NHTSA says higher levels of automation, where the system does all the driving, are not available to consumers today.
This article is general information, not safety or legal advice. Features differ by make, model and year. Always read your owner’s manual.
Why this matters
NHTSA reports that 39,254 people died in motor vehicle crashes in the US in 2024, and says many crashes are tied to human error. Driver-assistance technology aims to reduce that by warning drivers or stepping in. Many of these systems rely on cameras and sensors and on software that recognises lanes, vehicles and pedestrians. NHTSA’s pages explain what each system does, rather than how it is built, and that is what this article covers.
Warning systems
These alert you but don’t act on their own.
- Forward collision warning monitors your speed, the speed of the car ahead and the gap between you, and warns you if you get too close. NHTSA stresses that it “only provides a warning” and doesn’t take action.
- Lane departure warning watches lane markings and alerts you if you drift out of your lane. It also only warns.
- Blind spot warning alerts you, with a sound or a light, to vehicles in adjacent lanes you may not see when changing lanes.
- Rear cross traffic warning alerts you, when reversing, to possible collisions outside your backup camera’s view.
Systems that act
These can intervene.
- Automatic emergency braking (AEB) applies the brakes automatically to avoid or reduce the impact of a forward crash. NHTSA calls AEB “the next wave of potentially significant advances in vehicle safety.”
- Pedestrian AEB uses forward sensors to detect a pedestrian in your path and brakes if you haven’t acted.
- Rear automatic braking uses parking sensors and the backup camera to brake if a collision is likely in reverse.
- Blind spot intervention applies light braking or steering input if you start changing lanes into a car you can’t see.
Systems that help you drive
- Adaptive cruise control adjusts your speed to keep a set distance from the car ahead.
- Lane centering assistance applies steering to keep the car centred in its lane, using a camera.
- Lane keeping assistance corrects the steering or brakes individual wheels if the car is about to drift out of its lane unintentionally.
Other systems NHTSA lists include automatic high beams and automatic crash notification, which alerts emergency responders and shares your location after a serious crash. Backup cameras are different: NHTSA says it has required them on all new vehicles since May 2018, and it adds that they are “not a replacement for mirrors or turning around to look.”
The levels of automation
NHTSA’s page shows automation in six levels:
| Level | Name used by NHTSA |
|---|---|
| 0 | Momentary driver assistance |
| 1 | Driver assistance |
| 2 | Additional assistance |
| 3 | Conditional automation |
| 4 | High automation |
| 5 | Full automation |
NHTSA’s key point is this: “even the highest level of driving automation available to consumers requires the full engagement and undivided attention of drivers.” It also says higher levels, called automated driving systems, “are not available to consumers today,” while advanced driver-assistance systems are what you can buy now. Be wary of marketing names that imply a car “drives itself.”
What to do as a driver
- Stay in charge. The system is an aid, not a replacement for your attention.
- Learn your car’s features, and what its warnings sound and look like. Names differ between manufacturers.
- Check what a used or new car actually has before buying. NHTSA’s site lets you search by vehicle for some features.
- Don’t expect the same performance in all conditions. Weather, faded lane markings and dirty sensors can limit what a system can do. NHTSA’s pages we read don’t list these limits, so your owner’s manual is the place to check.
Frequently asked questions
Is a car with “autopilot” self-driving? NHTSA says no car for sale to consumers is at the level where the driver can stop paying attention. Always follow your car’s instructions.
Does my car have AEB? Many recent cars do, but check your owner’s manual or ask a dealer.
Do these systems use AI? Most rely on cameras, sensors and software that recognise road scenes. How each carmaker builds its software varies, and NHTSA’s pages don’t go into it. For one example of a carmaker’s software platform, see our article on Toyota’s Arene software.
Information checked on: October 30, 2026. NHTSA updates its pages, so check the latest.
Sources
- NHTSA, Automated Vehicle Safety (nhtsa.gov)
- NHTSA, Driver Assistance Technologies (nhtsa.gov)