Rolling Retest Feature of Virginia's Ignition Interlock Law: Safety Device or Safety Hazard?

Thousands of drivers in Virginia and other states are now required to put a breath-testing Ignition Interlock device on their car. 

These devices are intended to prevent anybody with more than .02 alcohol on their breath from starting their car.  However, the law also requires the device to demand a "Rolling Retest" at random intervals after the car is on the road. 

Even as Virginia has tightened up the laws about texting and driving; and there is a growing campaign against distracted driving, this law requires a person to perform a complicated breath test while driving down the highway!  In point of fact, they say that you have two minutes to pull over and provide the test, so you don't have to do it while driving.   However, some folks can't pull over, and some cops will roust you if you stop alongside the highway to use your phone anyway!  

The exact text of the Virginia Rolling Retest law is pasted below.  

"Ignition interlock system" means a device that (i) connects a motor vehicle ignition system to an analyzer that measures a driver's blood alcohol content; (ii) prevents a motor vehicle ignition from starting if a driver's blood alcohol content exceeds 0.02 percent; and (iii) is equipped with the ability to perform a rolling retest and to electronically log the blood alcohol content during ignition, attempted ignition and rolling retest.

"Rolling retest" means a test of the vehicle operator's blood alcohol content required at random intervals during operation of the vehicle, which triggers the sounding of the horn and flashing of lights if (i) the test indicates that the operator has a blood alcohol content which exceeds 0.02 percent or (ii) the operator fails to take the test.

Virginia Code  § 18.2-270.1

Also, here is link to a great bit by comedian Dan Cummins, talking about his interlock device, describing the hazard that is actually created by this "safety device."