It’s Confirmed: Driving’s a Full-Time Job — How Texting Impairs Driving Performance

Tobey — Thu, 01 Sep 2011 14:55:21 +0000

Researchers and safety advocates have known for years that driving performance worsens when the driver is texting. Now we know just how much worse.

TTI research proves that keeping your eyes on the road really does make a difference. Texting while driving was found to double the reaction time of drivers, while myths, such as “texting while driving saves time,” were challenged by the study’s findings.

Federal statistics suggest that distracted driving contributes to as much as 20 percent of all fatal crashes, and that cell phones constitute the primary source of driver distraction. Researchers point to two numbers to illustrate the magnitude of the texting-while-driving problem: an estimated 5 billion text messages are sent each day in the United States, and at least 20 percent of all drivers have admitted to texting while driving.

The study consisted of three major steps. First, participants typed a story of their choice (usually a simple fairy tale) and also read and answered questions related to another story, both on their smart phone in a laboratory setting.

Each participant then navigated a test-track course involving both an open section and a section lined with construction barrels. Drivers first drove the course without texting and then repeated both lab tasks separately while driving through the course again. Throughout the test-track exercise, each participant’s reaction time to a periodic flashing light was recorded.

Reaction times with no texting activity were typically between one and two seconds. Reaction times while texting, however, were at least three to four seconds. Worse yet, drivers were more than 11 times more likely to miss the flashing light altogether when they were texting.

Texas Transportation Institute (TTI) Assistant Research Scientist Joel Cooper directed the study along with TTI colleagues Christine Yager, associate transportation researcher, and Sue Chrysler, manager of TTI’s Human Factors Program. The research involved 42 participants between the ages of 16 and 54 and was funded by the Southwest Region University Transportation Center.

In addition to the reaction-time element, researchers also measured each driver’s ability to maintain proper lane position and a constant speed. Major findings further documented the impairment of texting when compared to the controlled driving conditions. Drivers were less able to:

safely maintain their position in the driving lane when they were texting, and their swerving was worse in the open sections of the course than in the barreled sections.
maintain a constant speed while texting, tending to slow down in an effort to reduce the demand of the multiple tasks. By slowing down, a driver gains more time to correct for driving errors (such as the tendency to swerve while texting). Speed variance was also greater for texting drivers than for non-texting drivers.

This work will produce one of the first and only studies in the nation conducted in an actual driving environment. That distinction is important, researchers say, because while simulators are useful, the dynamics of an actual vehicle are different, and some driver cues can’t be replicated in a simulator. By using a closed course, researchers can create an environment similar to real-world driving conditions while providing a high degree of safety for the participants.

“Most research on texting and driving has been limited to driving simulators. This study involved participants driving an actual vehicle,” Yager says. “So one of the more important things we know now that we didn’t know before is that response times are even slower than we previously thought.”

The researchers also examined the productivity level of each driver, measuring the amount of texting activity they could perform while driving. Drivers were generally able to complete about half the exercise content behind the wheel compared to what they could do in the lab setting.

“There’s a general assumption by some people who believe they’re being more productive if they’re exchanging messages while they drive because they’re performing two tasks at once,” Cooper says. “But our findings suggest that the productivity level for each of those tasks drops to less than half what it should be. That indicates to us that texting while driving is not only unsafe, it’s also inefficient.”

The researchers say that another finding from the study dispels a common misconception that composing a text message is a more demanding task than reading one. In post-study interviews, a majority of study participants held that belief, but study results found significant impairment from both reading and writing.

“The findings of this study extend to other distracting activities involving reading and writing, such as checking email or Facebook, while driving,” notes Chrysler.

The total distance covered by each driver in the study was slightly less than 11 miles. In the interest of safety for both participants and the research staff, researchers minimized the complexity of the driving task, using a straight-line course that contained no hills, traffic or potential conflicts other than the construction-zone barrels. Consequently, the driving demands that participants encountered were considerably lower than those they would encounter under real-world conditions.

“It is frightening,” the researchers wrote, “to think of how much more poorly our participants may have performed if the driving conditions were more consistent with routine driving.”

TTI Studies Increased Crash Rates Along the DFW Connector

Tobey — Thu, 01 Sep 2011 14:35:16 +0000

Take a dynamic work zone that can change daily. Add distracted drivers. What do you get? That’s what the Texas Department of Transportation wanted to know. Jason Crawford, manager of the Texas Transportation Institute’s North Texas Region, began looking for answers.

What he and his team of researchers discovered is that more drivers are turning their attention away from driving while passing through a construction zone. The roadway in question is a $1 billion project known as the DFW Connector, which skirts the northwest side of the Dallas/Fort Worth International Airport. Over 200,000 motorists pass through it daily.

TTI researchers were asked to evaluate the work zone because of higher-than-normal crashes, especially at night and on weekends. A statistical review separated injury crashes from non-injury crashes. That analysis showed that injury crashes occurred less frequently than the national work zone average, while property damage crashes happened more often.

Researchers concluded that the higher night and weekend crash numbers were the result of driver distraction, since drivers failed to notice traffic flow changes resulting from lane and total freeway closures. Crawford notes, “There can’t be any lane closures during the day. All of the work that happens above traffic lanes or impacts highway lanes occurs overnight or on the weekends.”

Crawford describes the construction area as “one where you have a lot of merging traffic. You also have a lot of weaving traffic. There are temporary lane shifts the contractor has in place. If you’re not really paying attention and the lane shifts, you could sideswipe someone.”

Cell phones may be adding to the complexity of navigating the work zone. Average cell use while driving in the Dallas/Fort Worth area is 6 percent, according to National Highway Traffic Safety Administration estimates. TTI researchers noted 12 percent usage in the DFW Connector work zone. Researchers feel that cell phone use could be a contributing factor to increased property damage crashes, although data did not allow them to make a causal link.

“We’re trying to get drivers to slow down and pay attention. The landscape for that construction project can change almost on a daily basis as you’re going through. There are crashes. And, the rate of cell phone usage is twice what you’d normally see,” Crawford says.

The study determined that drivers do not accurately perceive the safety risks involved with distracted driving in a complex construction zone like the DFW Connector.

The contractor has already acted on the findings. “Since we came out with the cell phone study, the contractor has implemented a number of coordinated campaigns, through banners and bumper stickers,” says Crawford. “The campaigns encourage drivers to slow down and pay attention.” The banners state, “Please don’t text and drive. My Daddy Works Here,” and “Let us work safely. Drive 50 mph!”

“They’re trying to increase awareness, not only for their guys, but also for the motoring public,” Crawford explains.

The study also recommends changes to lane-shift locations and markings, lighting practices and site maintenance to make the DFW Connector the safest work zone possible.

Texas A&M Transportation Institute» driver awareness

It’s Confirmed: Driving’s a Full-Time Job — How Texting Impairs Driving Performance

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TTI Studies Increased Crash Rates Along the DFW Connector

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Safety Is No Laughing Matter

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