The companies that make and market smartphones like to tout all the things the devices can do. But they’ve been keeping quiet about one major advance: technology designed to stop motorists from texting while driving. At a time when U.S. traffic fatalities are spiking, their choice not to implement automated blocking is literally killing us.

This came to light in recent New York Times coverage of a product liability lawsuit related to a 2013 Texas crash in which a driver checking her iPhone for text messages hit another vehicle, killing two adults and leaving a child paralyzed.

Lawyers for the victims’ families turned up a revealing 2008 patent filing by Apple for technology that would automatically lock out calls and texts after using sensors to determine whether a phone was moving and being used by a driver. Apple got its patent in 2014 but hasn’t put the technology in place.

Instead, the maker of the world’s most popular smartphone is emphasizing what drivers can do to keep from being distracted, like turning off their phones, manually disabling texting or using voice commands to compose or listen to text messages. Other companies encourage motorists to use apps to stop incoming texts.

This approach not only lets wireless companies off the hook but also overlooks the compulsive nature of smartphone use. Almost all adult motorists know that texting while driving isn’t safe, according to an AT&T survey. Vehicle safety research has shown that texting while driving triples a driver’s crash risk.

Almost half of us, though, do it anyway. Why? The “ping” of an incoming text activates the part of the brain that enjoys and expects pleasure, like being contacted by a friend or loved one, a University of Connecticut researcher has found.

And if nothing bad happens when we combine driving with sending messages, we eventually convince ourselves that we’re good at multitasking, despite the science supporting the other side — including the latest traffic fatality figures, which show a 7.2 percent jump in U.S. motor vehicle deaths between 2014 and 2015.

While weaknesses in the collection and investigation of crash data mean that it’s unclear exactly how many of these tragic accidents were caused by distracted driving, the risks of on-the-road smartphone use are clear, not just to motorists and scientists but also to wireless companies, the recent Times article pointed out.

It’s no coincidence that the 2014-2015 surge in crash deaths is the biggest spike since 1965-1966 — two years before the U.S. government mandated seat belts, the first in a number of safety features that have cut traffic deaths nationwide. Smartphone companies have a tool of their own that could be equally effective, and there’s no justification for not requiring them to use it.