Headlines today, all citing the same study by the Virginia Tech Transportation Institute:

From the press release for the study (emphasis mine):

In VTTI’s studies that included light vehicle drivers and truck drivers, manual manipulation of phones such as dialing and texting of the cell phone lead to a substantial increase in the risk of being involved in a safety?critical event (e.g., crash or near crash). However, talking or listening increased risk much less for light vehicles and not at all for trucks. Text messaging on a cell phone was associated with the highest risk of all cell phone related tasks.

From a New York Times article containing further detail about the VTTI study (emphasis again mine):

In the two studies, there were 21 crashes and 197 near crashes — defined as an imminent collision narrowly avoided — from a variety of causes, including texting. There were also about 3,000 other near crashes that were somewhat easier for the truckers to avoid, the researchers said. There also were 1,200 unintended lane deviations.To determine how the events compared to safer conditions, the researchers compared what occurred in the dangerous situations to 20,000 segments of videotape chosen at random.

In the case of texting, the software detected 31 near crashes in which the cameras confirmed the trucker was texting, though no actual collisions occurred. In the random moments of videotape, there were six instances of truckers’ texting that did not result in the software detecting a dangerous situation.

I couldn’t find the study data on the VTTI web site, but I found some PowerPoint presentations and other documents about the study. None of them quoted a “crash risk.” The increased risks were for “crash/near crash” incidents. The numbers quoted by the Times make it pretty clear that “crash/near crash” included crashes, near crashes, “other near crashes” and unintended lane deviations, because that’s the only way the odds ratio comes out to 23:

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Do I think texting while driving is a bad idea? Yes. Do I think you’re 23 times more likely to have an accident while texting than while not texting? I don’t know. The VTTI study suggests not, and it might suggest the opposite: while texting, you’re less likely to have an accident (but more likely to brake, swerve, or change lanes unintentionally). I can’t say whether the study suggests either of these things with statistical significance, because I don’t have the data, but it does seem to be the case that the study subjects, when texting, were more likely to swerve or slam on their brakes, but not crash.

I can think of some possible reasons for this, too: if you’re texting, you’re probably not sleeping (sleeping being a significant risk factor for actual crashes, but probably not for swerving and braking), and if you’re texting, you might know you’re creating a dangerous situation and be more prepared to swerve or brake suddenly.