California residents who use Apple CarPlay to access their iPhone while driving probably know that the system is supposed to reduce distraction. However, a study from the road safety charity IAM RoadSmart has cast doubt on Apple’s claims. In fact, using CarPlay may be more dangerous than texting or driving while high on marijuana.

As part of the study, 20 drivers in a simulation were asked to travel a route three times: once without using CarPlay, once while using voice commands to carry out tasks and once while using touch controls for those same tasks. The simulator recorded drivers’ reaction times and checked their ability to maintain a safe speed and stay in their lane.

Researchers found that drivers’ reaction times increased 36% and 57% when drivers used, respectively, the CarPlay voice and touch controls. Compare this to the 35% increase found in drivers who text and the 21% increase in those impaired by marijuana. The study also analyzed 20 other drivers who used Android Auto. The results were similar as reaction times rose 30% and 53% for Android Auto’s voice and touch controls.

Further research is needed to show why CarPlay is so distracting. The study’s authors suggest that drivers perceive built-in screens to be safer than handheld ones. The extra features may also contribute to inattention.

It should also be kept in mind that drivers can be distracted by everything from billboards to food and conversations with passengers. It’s not always technology that causes negligence. Nevertheless, distracted drivers are responsible for the accidents they cause, and victims may file a personal injury claim against such a driver’s insurance company in the effort to be reimbursed for medical bills and other losses. They may want a lawyer to assist with the filing and negotiating.