Safety benefits stack up from driver assistance features: IIHS

Washington, DC (Apr. 26, 2026) – The safety benefits from features like automatic emergency braking, lane departure prevention and high-beam assist stack up as multiple systems are bundled together and updated versions deliver better results, a new study from the Highway Loss Data Institute shows.

“These technologies are awesome,” said Matt Moore, chief insurance operations officer at HLDI and the Insurance Institute for Highway Safety. “As they improve and become more common, we are seeing compounding crash reductions.”

To better understand this evolution, HLDI’s latest study examined the impact of the advanced driver assistance systems offered on 2015-23 Mazda vehicles, comparing six feature bundles and four other stand-alone systems.

The most basic bundle consisted of a single feature — front automatic emergency braking (AEB), which in all these vehicles included forward collision warning. The most comprehensive bundle included front AEB with pedestrian detection, adaptive cruise control, high-beam assist, lane departure warning, lane departure prevention, rear AEB, and Driver Attention Alert — a feature designed to detect when the driver is fatigued or distracted.

Bigger bundles, bigger benefits

Not only were the larger bundles more comprehensive, but they also included more advanced versions of the technologies in the smaller bundles. That’s because they were offered on newer vehicles. At the same time as Mazda was introducing new features, it was refining the older ones. Thus, while all the bundles included front AEB, the biggest bundles included a more advanced version of it.

The reductions in claim frequency were substantial, especially under property damage liability (PDL) and bodily injury liability (BIL) coverages. PDL coverage pays for crash damage that the at-fault driver’s vehicle causes to other people’s vehicles or property. BIL coverage pays to treat injuries caused to people in other vehicles or other road users.

The most basic bundle was associated with a 13% reduction in PDL claim rates and a 9% reduction in BIL claim rates. In general, those benefits grew with the addition of each new technology, and the most comprehensive bundle was linked to a 39% drop in PDL claim rates and a 21% fall in BIL claim rates, though the latter figure was not statistically significant.

The bundle that added Driver Attention Alert was a notable exception, delivering no greater benefits with the addition of the new feature. It’s possible that the alert came into play too rarely to affect claim rates, as it only activates after about 20 minutes of driving between 41 mph and 86 mph and may not function on roads without clear lane markings.

The most noticeable added reductions came with the addition of front AEB with pedestrian detection and rear AEB. Along with reducing pedestrian crashes, the updated front AEB systems were most likely better than their predecessors at preventing crashes with other vehicles. Rear AEB delivered big benefits because it prevents many of the low-speed parking lot incidents that make up the bulk of insurance claims.

“If you’re worried about rising repair costs, the smartest thing you can do is get a vehicle with rear AEB and make sure it is turned on,” Moore said.

Effective stand-alone systems

In addition to the bundles, HLDI was able to evaluate the effects of several other features.

Blind spot detection and rear cross traffic alert, which detects vehicles approaching from the side when the driver is backing up, could not be assessed separately because in Mazda vehicles they come together. Both use the same radar sensors in the rear bumper. The combination was associated with a nearly 10% reduction in PDL claim frequency and a 13% reduction in BIL claim frequency.

Curve-adaptive headlights and the heads-up display, which projects key information such as the vehicle speed and navigation guidance directly onto the windshield, were each associated with slightly smaller reductions.

In contrast, the effects of a feature called Traffic Sign Recognition were unclear. This feature uses a forward-sensing camera or recorded information in the navigation system to identify and display traffic signs such as speed limit and stop signs. The lack of a clear benefit may stem from system limitations or may simply be the result of a small sample size, since fewer vehicles are equipped with it than other features.

Most bundles and individual systems were associated with increases in claim severity, which represents the cost paid to settle the claim. In part, those increases represent the higher cost of replacing sensors and other components that the crash avoidance systems rely on, which are often damaged in the crashes that do occur. However, another important factor is that crash avoidance systems primarily eliminate crashes that occur at slower speeds. That takes low-dollar claims out of the equation and skews the average cost upward.

A better indicator of the features’ economic impact can be found in the overall losses. The product of claim frequency and claim severity, it is the figure that affects the insurance company’s bottom line. All bundles and features except Traffic Sign Recognition were associated with lower overall losses under PDL coverage. A few were associated with minor increases under collision coverage, which covers damage to the policyholder’s own vehicle.

Read the original press release with charts, or download the complete study (24-page PDF).

About the Insurance Institute for Highway Safety

The Insurance Institute for Highway Safety (IIHS) is an independent, nonprofit scientific and educational organization dedicated to reducing deaths, injuries and property damage from motor vehicle crashes through research and evaluation and through education of consumers, policymakers and safety professionals. Learn more at www.iihs.org.

The Highway Loss Data Institute (HLDI) shares and supports this mission through scientific studies of insurance data representing the human and economic losses resulting from the ownership and operation of different types of vehicles and by publishing insurance loss results by vehicle make and model.

Both organizations are wholly supported by these auto insurers and insurance associations.

SOURCE: Insurance Institute for Highway Safety (IIHS)

Tags: advanced driver assistance systems (ADAS), Insurance Institute for Highway Safety (IIHS)