Safety Tech Features That Have the Strongest Evidence Behind Them

Automatic Emergency Braking (AEB) detects an imminent collision using cameras, radar, or a combination of both, and applies the brakes automatically if the driver doesn't respond in time. IIHS research has found that front AEB systems are associated with meaningful reductions in rear-end crashes — both in frequency and severity — and systems that detect pedestrians have shown additional benefits for reducing pedestrian-involved crashes.

AEB is arguably the single most evidence-backed active safety feature available on passenger vehicles today. NHTSA has moved toward requiring it as standard equipment on new vehicles, which reflects its documented impact. Keep in mind that AEB systems vary — some activate only at low speeds, while others are effective across a wider speed range. Understanding those differences matters when comparing vehicles. See our detailed explanation at Automatic Emergency Braking: What Triggers It and What It Can't Do.

Lane Departure Warning alerts the driver when the vehicle drifts across a lane marking without a turn signal active. Lane Keeping Assist goes a step further by applying gentle steering input to guide the vehicle back within the lane. Roadway departure crashes — where a vehicle leaves its lane and strikes another vehicle, a barrier, or leaves the road — account for a significant share of serious and fatal crashes in the U.S.

IIHS studies have linked LDW systems to reductions in injury crashes involving lane departures, and LKA provides an additional layer of intervention when the driver doesn't respond to an alert. Together, these systems target a crash type that is both common and frequently fatal, which is why researchers place them among the higher-priority technologies for real-world impact.

Blind-Spot Monitoring uses radar sensors to detect vehicles in the zones alongside and slightly behind your vehicle that mirrors don't fully reveal. A visual indicator — typically in the mirror housing — alerts the driver when a vehicle is present in that zone. Many systems add an audible or tactile alert if you activate the turn signal while a vehicle is detected.

Research from IIHS has found that BSM is associated with reductions in lane-change crashes, which are a common source of property damage and injuries on highways. While the effect size is more modest than AEB, the crash type it addresses happens frequently enough that the cumulative benefit across a vehicle's lifetime is meaningful. Rear Cross-Traffic Alert, which often pairs with BSM, extends similar protection when reversing out of parking spaces.

Rear AEB applies the brakes automatically when the vehicle detects an obstacle while reversing. This is distinct from a standard rear-view camera or parking sensors, which only alert the driver — rear AEB intervenes physically if the driver doesn't stop in time. IIHS research has found rear AEB is associated with reductions in backing crashes, which disproportionately involve children, pedestrians, and objects in tight spaces.

Backing crashes may seem minor compared to highway collisions, but they account for a notable share of pedestrian fatalities involving passenger vehicles. The physical intervention component is what separates rear AEB from alert-only systems in terms of documented impact.

Forward Collision Warning detects a closing gap to a vehicle or object ahead and alerts the driver — typically with an audible chime, a visual indicator on the windshield or dashboard, or both — giving them time to brake before AEB would activate. FCW and AEB are often paired, but they're functionally distinct: FCW notifies, AEB acts.

Research has found FCW alone reduces rear-end crashes compared to vehicles without it, though the effect is somewhat smaller than when AEB is also present. FCW's value is highest when the driver remains attentive enough to respond to the warning — which is exactly the scenario it's designed for. In vehicles where full AEB isn't available, FCW still provides a documented safety benefit.