Automated steering, braking and acceleration, whether in or out of traffic, is no safer than having a human driver do the same, an Insurance Institute for Highway Safety (IIHS) confirmed in a study published in July. Using crash records and insurance data, the IIHS found that this partial automation, including features like adaptive cruise control and lane keeping, offers little added benefit over simpler functions like automatic emergency braking.

The Highway Loss Data Institute (HLDI) conducted a 2021 study of BMW and Nissan vehicles that have been on the road for several years, finding that features that warn or intervene in an emergency reduce the frequency of insurance claims, and the reductions increase gradually as a feature stacks on another.

The difference between these and semi-automated features is that adaptive cruise, lane keeping, etc., usually need to be turned on to work, and most drivers only do so occasionally.

A new study from the IIHS confirmed the early, showing that “partial automation in these vehicles offers no additional safety benefits beyond those of crash avoidance features such as automatic front emergency braking (AEB).”

In the previous study, HLDI found that property damage liability claims were 8 percent lower for Nissan Rogues equipped with forward collision warning and AEB. But no benefit was added with adaptive cruise control or Nissan’s ProPilot Assist partial automation system. BMW and Mini told the same story. Forward collision warning and automatic emergency braking reduced both collisions and property damage, but BMW’s Driving Assistant Plus partial automation system did not further affect the numbers.

“With more and more automakers rolling out complete suites of ADAS technology, it is imperative for a consumer to understand how the assist function works, when it works and when it doesn’t, and its limitations (such as in adverse weather conditions, for example), said Robby DeGraff, director, product and consumer information at AutoPacific Newsweek.

“This responsibility falls equally on dealerships at the point of sale to explain to the new (or used) vehicle buyer, and on automakers to ensure that the terminology and marketing used to depict the safety assistance feature in question makes clear sense. Misunderstanding and overshooting these systems can be deadly,” he said.

HLDI data does not show whether the system was activated or the type or road where the insurance claim arose. To adjust for this, the IIHS limited its new study to front-end and lane-departure crashes that partial automation could potentially prevent. He came to the same conclusion about collision avoidance features.

However, the IIHS saw an initial benefit from the partially automated features before digging deeper into the data. It found that “the benefits of ProPilot Assist were the same on high-speed roads where IIHS research indicates that partial automation is more likely to be activated and on low-speed roads where the additional comfort it provides is minimal at best.”

The IIHS says it suggests other features of equipped vehicles or their drivers were responsible for the decline, including non-acceptable headlights, which increase a vehicle’s nighttime crashes by 15 percent over acceptable-rated headlights. For BMW, the IIHS found that neither lane departure prevention alone nor in combination with partial automation had a significant effect on crash rates.

“AutoPacific gauges consumer demand for various hands-on and hands-off autonomous driving systems available today and possibly on the horizon. Interest certainly varies, for example, our latest FADS (Future Attribute Demand Study) revealed the 23 percent of all new vehicle buyers surveyed want a hands-off, semi-autonomous highway-only system like GM’s Super Cruise or Ford’s Blue Cruise on a highway like Tesla’s Full Self Driving still in testing, it saw the biggest jump in demand (+6 percent, Regardless of the different level of range, younger consumers, men and candidates for electric vehicles want it the most.” DeGraff.

Previously, the IIHS evaluated partial automation systems from BMW, Ford, General Motors, Genesis, Lexus, Mercedes-Benz, Nissan, Tesla and Volvo. According to IIHS President David Harkey, “most of these do not include adequate measures to prevent misuse and prevent drivers from losing their attention to what is happening on the road.”

The IIHS said the Teammate system available on the Lexus LS is the only system tested that earns an acceptable rating. The best systems in the GMC Sierra and Nissan Ariya earn marginal scores. Partial Ford systems in the Mustang Mach-E, Genesis G90, Mercedes-Benz C-Class sedan, Tesla Model 3 and Volvo S90 also earn poor ratings.