Editor's note: This is another story in an occasional series about the epidemic of distracted driving and efforts to curb it.
By Marni Pyke
Think you can juggle coffee, a quick call to the boss and gridlock on the expressway?
Easy there, multitasker. Experts say you can't and it's just tempting fate to try.
When it comes to demanding actions such as driving and talking, our brains can't do two things at once, scientists explain.
"Your hands may be on the wheel but if your mind is off the road -- you're vision impaired," psychologist Joel Cooper said.
"Scientists have been unable to show people can truly multi-task -- doing two things at the same time as well as they do each individually."
Along with the myth of multi-tasking, safety advocates also want to debunk the popular notion that using hands-free phones is not a form of distracted driving.
A heated argument with your spouse absorbs the same attention away from the road whether it's on a cellphone or a hands-free system. Cognitively, it's just as dangerous, the Itasca-based National Safety Council reports after comparing more than 30 studies on cellphone use and driving.
"There's no difference in terms of safety," said Cooper, an assistant professor at the University of Utah and expert on distracted driving.
And that's why laws that ban cellphone use while driving but exempt hands-free devices give the public the mistaken impression you're safe as long as you don't hold a receiver, experts say.
"It sends a really bad message," said David Teater, National Safety Council senior director for transportation strategic initiatives.
Instead of exemptions for hands-free phones, more comprehensive laws are needed, safety experts say. Many, in fact, would like to see a total ban on cellphone use while driving.
If you've ever prided yourself on the ability to switch lanes while engaged in a phone conversation with your teenager, it's time for a reality check, safety advocates say.
Your brain is not doing both tasks at the same time. Instead, it shifts from job to job so rapidly you're not aware of the process.
"Switching between tasks is not truly multi-tasking, except for simple, basic things like breathing," University of Kansas cognitive psychologist Paul Atchley said.
While that may not matter if you're raking leaves and talking football with a neighbor, it's a crucial distinction when someone's behind the wheel.
As an accident reconstructionist, Kane County Sheriff's police Sgt. Craig Campbell investigates distracted driving crashes.
"When you're multi-tasking you're not giving 100 percent to any one task," Campbell said.
"When you're in charge of 3,500-plus pounds of metal, rubber and glass, it's imperative you pay full attention to the road."
When the brain is juggling actions, it can become overloaded, meaning not all available information is processed.
Studies have shown that drivers absorbed in cellphone conversations only recall 50 percent of the objects they pass on the road.
"It looks like you're looking down the road and have your hands on the wheel, but if you dig deeper, you're only processing half as much of the visual environment," Cooper said.
"We're trying to raise people's awareness of this invisible threat."
Carnegie Mellon University scientists took MRI images of the brains of study participants who drove on a simulator while listening to statements made on a cellphone. Next, they were asked to determine if the sentences were true or false. The images demonstrated less activity in areas of the brain used for vision, navigation and judging distance.
"Emotional conversations are particularly distracting. Conversations about directions are the worst," Atchley said.
Ever driven from one point to another without remembering how you got there?
This "inattention blindness" happens when drivers are cognitively distracted and the part of the brain that controls visual information isn't sending that data to the memory function.
"With a cellphone conversation, you can become so engrossed that you become blind to those driving cues you normally pick up on telling you to re-prioritize," Cooper explained.
A study by Transport Canada tracked the eye movements of drivers using hands-free phones and those without. The field of vision narrowed significantly with phones, meaning motorists missed out on traffic in other lanes, cut back on checking traffic lights and reduced monitoring of mirrors, researchers found.
Studies consistently revealed the same cognitive sins of omission among hands-free device drivers as those using conventional cellphones.
One University of Utah study found drivers with phones reacted more slowly than those with a .08 blood-alcohol concentration, the level at which drivers are presumed to be intoxicated and are violating the law.
"Drunk drivers are safer. They make mistakes, but they overcompensate by braking hard," said Atchley, who with Cooper has worked with the NSC on distracted driving issues.
These lost seconds are the difference between life and death, accident reconstructionist Campbell said. For example, at 55 mph, a car travels 80 feet per second.
"If you take your eyes off the road for half a second, you travel 40 feet and distracted drivers usually take their eyes off the road for longer than half a second," Campbell said.
"The difference between a serious crash and a crash with minor injuries is a matter of milliseconds."
Despite proof showing the dangers of hands-free phones, laws don't reflect that reality. In Illinois, the state bans cellphones in school and construction zones but permits hands-free devices. That policy is similar to Chicago's ban on hand-held cellphones.
It sends the erroneous message that if you're hands-free, you're safe, Teater said. He's encouraged, however, by recent polls showing an upswing in the number of people who view driving with hands-free phones dangerous.
"I think the public is starting to understand, and the more they understand, the more likelihood there is that laws get passed," Teater said.
Itasca police recently took the step of putting a slogan on the back of squad cars that reads, "Put down the phone & drive."
"There's a lot of drivers with cellphones both hands-free and hand-held that are accidents waiting to happen," Police Chief Scott Heher said.
"It's a complicated task -- it requires all your attention."