Partially automated vehicle systems encourage driver distraction, according to a safety group study.

Following the habits of a group of Volvo drivers and a group of Tesla drivers, the Insurance Institute of Highway Safety found that both tended to adapt to the two brands’ driver-assistance systems in order to engage in nondriving activities, including eating and, inevitably, looking at their phones.

The findings show that people are much more likely to multitask on the road when such systems are on. To enable their extracurricular activities, the drivers learned to engage with their vehicles at certain intervals in order to prevent more urgent warnings from the systems about their distraction, IIHS said.

“This demonstrates why partial automation systems need more robust safeguards to prevent misuse,” said David Harkey, the nonprofit group’s president, in a press release on the study result.

For obvious safety reasons, drivers should monitor progress down the road despite such systems being in operation so they can resume control if things go awry, IIHS said. Being distracted with nondriving activities can compromise that necessary alertness.

The distracted behavior took place despite the vehicle brand and its accompanying partial-automation system, and regardless of the level of city or highway driving study participants did. In fact, the longer the study went on, the more likely the drivers were to be driven to distraction.

LEARN MORE: Traffic Safety Group, Senators Call for ADS Scrutiny