In a move that surprised many, the National Transportation Safety Board recently urged states to ban all drivers from using cellular technology—including hands-free and Bluetooth sets. The board can neither pass such a law nor compel states to do so. But it raises a big question: How could employers communicate with mobile workers with no cell phones?

Employers can be liable. We spoke with Matt Howard, CEO of ZoomSafer, which provides technology intended to promote safe driving. Howard reports that 38 states regulate drivers’ use of wireless communication, but most ban only texting while driving. A few states, including Connecticut and California, require drivers to use only hands-free devices. And the federal Department of Transportation issued a rule effective January 3, 2012, that drivers of commercial motor vehicles may not use hand-held mobile phones. They may answer, place, or end a call if they can do so by pushing a single button or using, but not holding, a device within their reach. And the rule has teeth. Howard reports that a driver who violates it can be subject to a fine of $2,700.

His most urgent message to employers: If a “distracted driver”—the catch phrase for someone who texts or talks on the phone at the wheel—is driving a company-owned vehicle on business and causes an accident that injures or kills someone else, the employer can be found vicariously liable. And, judges are not looking kindly on employees who are reckless because they’re distracted. In one recent case, a train engineer was texting his girlfriend and missed warning signals and lights visible from as much as 450 feet away. Result? He plowed into a train stopped ahead of him, derailing many cars on both trains and injuring scores of people.

And Howard talks about a scary case in which he was involved. A recently hired commercial van driver in Ohio was texting while driving, drove over the median, and killed a 19-year-old college student. In court, the judge asked whether the employer had conducted a background check and a motor vehicle records review on the driver. The answer was yes to both. Had it checked his cell phone records? No. Those records would have shown that the driver routinely sent 5,000 texts each month. The employer paid hugely for the accident.

Hands-free doesn’t solve the problem. A 2009 study by researchers at the University of Utah reported that “equivalent deficits in driving performance were obtained for users of both hand-held and hands-free cell phones.” Connecticut passed its hands-free law in 2005. But the state had the largest percentage increase in traffic fatalities in the nation between 2009 and 2010, while fatalities nationwide dropped to their lowest number in six decades. And cell phone violations—only for drivers using hand-held sets—skyrocketed to more than 10,000 in 2010.

Comments Howard, “Fear and greed, unfortunately, drive most of our behavior. Laws won’t do it. Picking up the phone when it beeps or boops is a Pavlovian response.” With 6 million people driving employer-provided vehicles equipped with employer-provided smartphones, “The amount of potential liability is huge.” And if the employee is driving a personal vehicle and using a personal cell phone? If his boss texts or calls him about an upcoming sales meeting, and the employee crashes while answering, the employer can be liable for any damage or injuries.

What can employers do? ZoomSafer and several other companies, including Cellcontrol, make and sell devices that can be installed in company vehicles to block all cell signals except calls to 911. The software senses when a vehicle is moving and begins blocking signals. It is sensitive enough to detect speeds of more than 0 miles per hour, but employers can, if they wish, set them to block only at higher speeds. “Different employers have different levels of tolerance for risk,” says Howard, “ranging from 0 percent all the way up to 100 percent, so they can vary their settings accordingly.”

Settings could also be varied according to whether an individual driver’s route is in a busy or densely populated area, as opposed to a more rural one. Note that similar devices designed for consumers that can block the cell signals of other mobile phone users are illegal, according to the Federal Communications Commission. ZoomSafer’s technology blocks signals only to and from the cell phone in the commercial vehicle where it’s installed. Consumers can buy and have installed similar devices for personal cars, such as the vehicle that a newly licensed teenager will be driving.

Will states adopt NTSB’s recommendation? Howard believes that’s highly unlikely in the near future, although he does acknowledge that the federal government’s positions on seat belt use, blood alcohol levels, and speed limits have been widely influential. He believes that the current trend at both state and federal levels is to promote hands-free rules; there are currently two bills in Congress to that effect. And, he says, even adopting NTSB’s rule won’t solve the problem. “Laws and regulations are easy, but they don’t change behavior. Technology does change behavior.” For more information, see http://ZoomSafer.com.