Pay first for a car that scores Good in the current crash tests, then for automatic emergency braking, Good-rated headlights, blind-spot monitoring and rear automatic braking. Those are the features with measured crash reductions in IIHS studies (50% fewer rear-end crashes, 19% fewer nighttime crashes, 14% fewer lane-change crashes, 78% fewer backing crashes). Partial automation has no demonstrated crash-reduction benefit and belongs last: only 1 of the 14 systems IIHS has rated earn Acceptable or better for keeping the driver engaged.
Safety features ranked by evidence
Each reduction is the IIHS estimate for the crash types the feature targets, from the study linked in the row. A feature can be valuable and still sit lower because it addresses fewer crashes or has less evidence behind it.
| Priority | Feature | What it does | Measured crash reduction (source) | What to verify on the trim |
|---|---|---|---|---|
| Foundation | Good crash-test results and rear-seat restraints | Occupant protection when a crash is not avoided. | Not a single percentage: the crash tests are the base every avoidance feature sits on. Cars rated Good in the current IIHS tests are the starting filter for every ranking on this site. IIHS ratings | Exact model year, body style, build date and the rear-passenger result in the updated moderate overlap test. |
| High | Automatic emergency braking (AEB) with forward collision warning | Warns of an imminent frontal crash and brakes if the driver does not. | Rear-end crashes cut 27% (warning only), 43% (low-speed autobrake), 50% (warning plus autobrake); injury rear-end crashes cut 56%. IIHS ref 2111 (Cicchino 2017) | The IIHS pedestrian and vehicle-to-vehicle front crash prevention results for the exact model year; whether AEB is standard on the trim. |
| High | Good-rated headlights | Lights the road far enough ahead to react at night. | Good-rated headlights linked to 19% fewer nighttime single-vehicle crashes, 23% fewer nighttime pedestrian crashes and 29% fewer nighttime injury crashes than Poor-rated lights. IIHS headlights research | The rating for the specific headlight package on the trim you buy, not the model. |
| Strong | Blind-spot monitoring | Warns of a vehicle alongside in an adjacent lane. | Lane-change crashes 14% lower; injury lane-change crashes 23% lower (the injury estimate was not statistically significant). IIHS ref 2143 | Both sides covered; warning only or active steering/braking intervention. |
| Strong | Rear automatic braking with camera and sensors | Brakes when a backing collision is imminent. | Backing crashes 78% lower for vehicles with a camera, parking sensors and rear autobrake combined; rear cross-traffic alert alone 22% lower. IIHS park-assist study | Whether the trim includes braking, not just a camera or sensors. |
| Useful | Lane departure warning or prevention | Warns, or briefly steers, when the car drifts out of its lane. | Single-vehicle, sideswipe and head-on crashes 11% lower; injury crashes of those types 21% lower. IIHS ref 2142 | Vibration versus beep warnings (vibration systems stay switched on more often); whether it steers or only warns. |
| Baseline | Electronic stability control (ESC) | Brakes individual wheels to stop a skid or spin. | Roughly halves the risk of a fatal single-vehicle crash. Required on all new U.S. passenger vehicles from model year 2012, so it is a used-car check, not an option. IIHS ESC study | Present and no fault light on any vehicle older than 2012. |
| Last | Partial automation (adaptive cruise plus lane centering, "hands-free" packages) | Holds speed, distance and lane position while the driver supervises. | No measured crash reduction beyond the AEB and lane-keeping features it is built on. IIHS rates only its driver-engagement safeguards, not a safety benefit. IIHS safeguard ratings | The IIHS safeguard rating for the exact system and software version; what it does when you stop looking at the road. |
This is a purchasing order, not a score. The percentages come from IIHS comparisons of the same models with and without each feature in police-reported crash data; they describe the studied systems and crash types, not every car or every situation.
What our 197 current models show
The catch with every feature above is that the rating belongs to a specific trim, package or software version, not to the model name. These counts come from the current IIHS records behind our ranking.
Pedestrian automatic braking, current models
The IIHS pedestrian test runs day and night at several speeds, so "has AEB" and "brakes for a pedestrian at night" are different claims. Of the 174 current models with a result:
| Good | 81 |
|---|---|
| Acceptable | 64 |
| Marginal | 8 |
| Poor | 21 |
Pedestrian front crash prevention is worth 10% of our safety score; the per-model result is on every ranking page. Headlights are shown per model but not scored, because on 25% of rated models the answer depends on the package.
Automatic emergency braking: the clearest payoff
Forward collision warning alerts the driver; automatic emergency braking applies the brakes when a frontal crash is imminent. In the IIHS comparison of police-reported crashes, warning alone was linked to 27% fewer rear-end crashes, low-speed autobrake to 43% fewer, and warning plus autobrake to 50% fewer, with injury rear-end crashes down 56%. Pedestrian AEB was linked to 27% fewer pedestrian crashes overall, but the early systems showed no benefit on unlit roads at night, which is why the current IIHS test includes nighttime runs.
The label is not enough. The current IIHS vehicle-to-vehicle test approaches stopped targets at 31, 37 and 43 mph, offsets a passenger-car and a motorcycle target, and checks the warning against a semitrailer. Systems that mastered the old low-speed test separate sharply here, so open the front crash prevention result for the exact model year instead of trusting "AEB standard" on a listing.
Is AEB mandatory? NHTSA's FMVSS 127 requires AEB, pedestrian AEB and forward collision warning on nearly all new light vehicles from September 1, 2029. In March 2026 the Department of Transportation told the D.C. Circuit it is preparing a notice of proposed rulemaking to amend parts of the standard, so treat the rule as under review rather than settled. Either way it says nothing about how well today's systems perform.
Five-minute AEB check: confirm the equipment by VIN or window sticker; open the IIHS rating for that model year and read both the vehicle-to-vehicle and pedestrian results; check for trim or build-date splits; make sure no driver-assistance warning stays lit after start-up; and ask for calibration records if the windshield, grille, bumper or radar has been replaced. Do not try to trigger AEB on a test drive.
Blind spot and backing: buy the system that can act
Blind-spot monitoring watches the adjacent lanes while you drive forward; IIHS found 14% fewer lane-change crashes for equipped models (23% fewer injury crashes, not statistically significant). Some cars add blind-spot intervention, which brakes or steers lightly when you start moving toward an occupied lane. A warning and an intervention are not the same feature even when the names sound alike.
For backing, four features do four different jobs: a camera shows, parking sensors warn about nearby objects, rear cross-traffic alert detects vehicles approaching from the side, and rear automatic braking can stop the car. IIHS measured 22% fewer backing crashes with rear cross-traffic alert alone and 78% fewer with a camera, sensors and rear autobrake together. Backup cameras have been required since May 2018, so the camera is the baseline; the braking is the upgrade worth paying for.
On the test drive: look for a blind-spot icon in the mirror rather than far away on the dash; check that the warning escalates with a sound or vibration when the turn signal is on; confirm whether rear braking is standard on this trim or only the sensors are; and check that the settings survive a restart. On a used car, a minor rear-corner bump can knock a radar sensor out of alignment without visible damage, so ask for a driver-assistance scan after any bumper or quarter-panel repair.
Lane support: warning, prevention and centering are three different things
Lane departure warning alerts you after the car begins drifting. Lane-keeping assist or lane departure prevention adds a brief steering or braking correction. Lane centering steers continuously and, paired with adaptive cruise control, becomes partial automation. IIHS found lane departure warning was linked to 11% fewer of the single-vehicle, sideswipe and head-on crashes it targets, and 21% fewer injury crashes of those types.
Two details decide whether you get that benefit. First, the system needs visible lane markings, so its value is higher for highway commuters than for slow urban trips. Second, a warning that annoys the driver gets switched off: IIHS-summarized research found vibration-based warnings were more likely to stay on than beeping ones. Evidence for basic lane departure warning should not be borrowed for lane centering; IIHS reports no crash-reduction advantage for partial automation over the same cars with only crash-avoidance features.
Six questions for the test drive:
- Can you feel and understand the warning without looking away from the road?
- Does the system tell a signaled lane change apart from drifting?
- Is the steering correction smooth and easy to override?
- Can warning timing or intensity be adjusted rather than switched off?
- Does the setting stay on after the car is restarted?
- Does the display clearly show when lane lines are detected?
On a used car, ask whether the forward camera was recalibrated after any windshield replacement; it is usually mounted to the glass.
Partial automation: convenience, not a safety upgrade
Packages sold as highway assist, hands-free or pilot systems combine adaptive cruise control and lane centering. The driver still has to watch the road and take over instantly. IIHS rates these systems only on the safeguards that keep the driver engaged (monitoring, escalating alerts, emergency stops, lockouts), and in its 2024 round 11 of 14 systems rated Poor, 2 Marginal and 1 Acceptable. The full table, including what each system does when you stop paying attention, is on our partial automation safeguard ratings page.
If two cars are otherwise equal, prefer the system with stronger safeguards. But a package costing thousands should not displace better crash results, headlights, tires or the proven avoidance features above.
Before paying for any package, ask five questions: Is the feature standard on this exact VIN or only available on the model? Has IIHS tested its performance? Does the result apply to the installed headlights, sensors and build date? Does the system warn, intervene or both? Is any windshield, bumper, radar or camera damaged or due for calibration?
Questions people ask
Which car safety feature has the biggest proven benefit?
Automatic emergency braking with forward collision warning. IIHS found 50% fewer police-reported rear-end crashes and 56% fewer injury rear-end crashes for equipped vehicles. For backing crashes, the combination of a camera, parking sensors and rear automatic braking cut crashes 78%.
Are good headlights really worth paying extra for?
Yes. IIHS found that Good-rated headlights were linked to 19% fewer nighttime single-vehicle crashes and 23% fewer nighttime pedestrian crashes than Poor-rated headlights. On 43 of the 173 current models with a headlight rating in our data, the rating depends on the trim or option package, so check the exact package before assuming the model is rated Good.
Is a hands-free driving package a safety feature?
Not by the evidence available today. IIHS says there is no evidence that partial automation reduces crashes beyond the AEB and lane-keeping features it is built on, and only 1 of the 14 systems it has rated earned Acceptable or better for driver-engagement safeguards. Treat it as a convenience and pay for crash tests, AEB and headlights first.
Is automatic emergency braking required on new cars?
Not yet. NHTSA finalized FMVSS 127 in 2024 with a compliance date of September 1, 2029, but in March 2026 the Department of Transportation told the D.C. Circuit it is preparing a proposed rule to amend parts of the standard. The 2029 date stands today but is under review, so check the IIHS front crash prevention rating for the exact model rather than relying on the mandate.
Do I need to pay for electronic stability control?
No. ESC has been required on every new U.S. passenger vehicle since model year 2012 and IIHS estimates it roughly halves the risk of a fatal single-vehicle crash. On a used car older than 2012, confirm it is fitted and that no fault light stays on.
Keep comparing
Sources
- IIHS: effectiveness of forward collision warning and automatic emergency braking (ref 2111)
- IIHS: headlights research
- IIHS: effects of blind-spot monitoring on lane-change crashes (ref 2143)
- IIHS: park-assist technology and backing crashes
- IIHS: effects of lane departure warning on police-reported crashes (ref 2142)
- IIHS: life-saving benefits of electronic stability control
- IIHS: how vehicle-to-vehicle front crash prevention is tested
- IIHS: advanced driver assistance research overview
- IIHS: partial automation safeguard ratings
- NHTSA: FMVSS 127 automatic emergency braking final rule; status of the March 2026 DOT notice of proposed rulemaking
- NHTSA: driver assistance technologies