There have been studies that compare text messaging on cellphones and other hand-held devices to driving drunk. And several states have already banned texting while driving. But according to Car and Driver, no one has done a real-world test — until now.

In an article that appears in the current issue of the magazine, the editors hooked up a Honda Pilot with a red light on the windshield. Car & Driver’s editor and chief, Eddie Alterman, 37, and the magazine’s intern, Jordan Brown, 22, both took turns behind the wheel on a test track. When the light came on, the drivers hit the brakes.

From Car and Driver:

First, we tested both drivers’ reaction times at 35 m.p.h. and 70 m.p.h. to get baseline readings. Then we repeated the driving procedure while they read a text message aloud (a series of Caddyshack quotes). This was followed by a trial with the drivers typing the same message they had just received. Both of our lab rats were instructed to use their phones exactly as they would on a public road, which, if Jordan’s mom or Eddie’s wife are reading this, they never do.

Our test subjects then got out of the vehicle and concentrated on getting slightly intoxicated. They wanted something that would work quickly: screwdrivers (vodka and orange juice). Between the two of them, they knocked back all but three ounces of a fifth of Smirnoff. Soon they were laughing at all our jokes, asking for cigarettes, and telling us about some previous time they got drunk that was totally awesome. We had them blow into a Lifeloc FC10 breath-alcohol analyzer until they reached the legal driving limit of 0.08 percent blood-alcohol content. We then put them behind the wheel and ran the light-and-brake test without any texting distraction.

Car and Driver performed each test five times, dropping the slowest time. The magazine found that reaction time was much worse for both drivers when they were texting while driving than when they were under the influence of alcohol.

At 35 miles an hour, Mr. Alterman’s average reaction time was .57 seconds, but while texting it rose to 1.36 seconds, more than twice his average reaction time of .64 seconds while under the influence. Mr. Brown fared better, but his average reaction time of .45 seconds rose to .52 seconds while texting, worse than his average time of .46 seconds while driving drunk.

The results of the tests at 70 miles an hour were better in terms of reaction times. But at highway speeds, the extra distance traveled before coming to a complete stop was much greater. For example, Mr. Alterman traveled an average of four feet farther while driving drunk and an average of 70 feet farther while texting.

“The prognosis doesn’t improve when you look at the limitations of our test,” writes Mike Austin, the author of the Car and Driver article. “We were using a straight road without any traffic, road signals, or pedestrians, and we were only looking at reaction times.”

Copyright 2009 The New York Times Company