It’s actually worse than we thought. If you study the statistics on highway fatalities related to cellphone use, things don’t look all that bad. New York reported only one death related to using a phone in 2011, and Louisiana didn’t have any at all.

But according to the National Safety Council (NSC), this may have more to do with the way information is gathered (and the way records are kept) than the actual mayhem on the highways. NSC studied 180 fatal crashes in the two-year period between 2009 and 2011 involving driver phone use, and it found that only slightly more than half of them (52 percent) had made into national statistics on cell fatalities.

NSC thinks the actual number of such deaths is “much greater than what is being reported,” said Janet Froetscher, NSC president and CEO. The group thinks, based on national highway statistics, that it’s likely that a quarter of all crashes, including minor fender benders, involve cellphones. Fatalities on the roads were up more than 5 percent in 2012, the first increase in seven years.

John Ulczycki, a vice president of NSC, told me that the group has concluded that the federal database is so incomplete that the feds should stop trying to compile accurate numbers. Instead, he said, it would be better to make an informed estimate of such deaths, which is the current practice with drunk driving. Ulczycki said that his group's study was very thorough, in many cases looking at court cases arising from fatal crashes, because cellphone use is often uncovered during that process. "The police are looking for illegal activity, and cellphone use isn't even illegal," he said. "They're more likely to look for running stop lights or something like that."

Drivers often don’t admit using their phone after a crash, and in some cases — as when a solo driver dies in an accident — it’s impossible to accurately measure the phone’s role. But even in cases where drivers were upfront about electronic distraction being a factor, only half were reported nationally.

The state reporting data that is used to compile the federal stats is deeply suspect because it’s so inconsistent. In 2011, when New York supposedly had one fatal cell crash and Louisiana had zero, Tennessee reported 93. That same year, Texas reported 40, which also seems low.

Only 10 states have laws prohibiting the use of hand-held phones by driving adults. Now here’s a shocker: David Teater, an NSC senior director, told me that there’s really no difference in the danger between hand-held and hands-free phone use. “The problem is the cognitive distraction,” he said. More than 30 studies have looked at the supposed benefits of hands-free phones and they haven’t been able to find any.”

It’s the multi-tasking that impairs the performance, not holding the phone, an NSC white paper says. “A driver’s response to sudden hazards, such as another driver’s behavior, weather conditions, work zones, animals or objects in the roadway, often is the critical factor between a crash and a near-crash,” the report said. “When the brain is experiencing an increased workload, information processing slows and a driver is much less likely to respond to unexpected hazards in time to avoid a crash.”

It's all in this paper, “Understanding the Distracted Brain.” Read it here.

Jim Motavalli ( @jmotavalli ) writes about cars, technology and the environmental world to anyone curious enough to ask.

Cellphone driving deaths: Toll is higher than you think
National Safety Council study shows that cell-related traffic fatalities are significantly under-reported. And hands-free laws don't matter.