According to the Financial Times1, “GM is preparing to launch the world’s first mass-produced cars with eye- and head-tracking technology that can tell whether drivers are distracted, according to people with knowledge of the plans.”  There is no mention in the article when this launch would take place, nor does the article specifically mention that the technology could also be used to stop—or at least deter—intoxicated driving.

Scientific research into the plausibility of using eye tracking to identify intoxication has been going on for years.  In law enforcement, suspected drunk drivers are often given a horizontal gaze nystagmus (“HGN”) roadside sobriety test.  This simple test involves a properly trained police officer asking the drunk driving suspect to follow his/her finger with the eyes only.  The officer then observes the driver’s eyes closely, and if they begin to jerk while moving across a horizontal plane (from side to side), it is possible that the driver is intoxicated.

The HGN test has been used in this manner by law enforcement since at least the late 1970s when Dr. Marcella Burns began her research into standardizing field sobriety testing.  Training in the proper administration of HGN has since become commonplace.  Whether or not the police follow this training is, of course, a whole different matter2, but the science behind the HGN test itself appears sound.

The scientific study of human eye movements began in the late 19th century and employed a variety of measurement techniques.3  In the late 1940s, researchers used cameras to record the eye movements of pilots in the cockpit.4  It was the advent of digital technology and image processing in the 1970s that marked the opening of a new era of video-based eye monitoring.5  Today, many companies offer video-based eye monitoring systems at affordable prices.6

Ethanol’s effects on eye movements are well known.  Ethanol intoxication slows the initiation and the velocity of saccadic eye movements and, most importantly, reduces the gain of slow eye movements.7  Saccades are rapid, ballistic movements of the eyes that abruptly change the point of fixation.  They range in amplitude from the small movements made while reading, for example, to the much larger movements made while gazing around a room.8

The technology necessary to prevent drunk driving based on eye movement is not new.  In 1995, a patent was granted for technology that would - according to the patent application abstract - offer an integrated vehicle operator monitoring system for a vehicle including a device for monitoring operator identity to ensure a vehicle operator is authorized to operate the vehicle, a device for monitoring operator intoxication, and a device for monitoring operator drowsiness.9

There are, of course, limitations to the use of this technology.  “Personal calibration is necessary because individual differences constitute some of the most important factors contributing to gaze tracking errors.  This task is a troublesome process for users of passive eye monitoring systems because it requires the user to cooperate by looking at a series of reference points (around twenty markers).  Another major problem that limits the use of passive eye-gaze monitoring is that the user’s head must remain within a limited volume.”10  It would seem however that this limitation may not be as much a problem for an automobile since the driver’s head tends to stay in approximately the same place, though any driver can recount instances of reaching down at a stop light to pick up a fallen object, and any parent can recount looking to the back seat to shush noisy children.

Aside from the possible limitations, in order for eye-movement technology to become widespread in automobiles, it would have to be passive (requiring little to no driver interaction to operate), seamless (the driver need not even be aware of its presence), and inexpensive.  It would appear that eye-movement technology has the potential to satisfy all three of these criteria.

Assuming that the technology goes into the 2016 GM vehicle launch, the question becomes: how long before it begins to positively impact driver safety?  It seems like it will take a long time, at least 10 years or more.  This is true even if GM remains at or near the top for vehicles sold because in 2013 there were 15.6 million vehicles sold according to NYDailyNews,11 but only 2.8 million of these were GM vehicles.12  Also, there are currently somewhere around 254 million registered vehicles in the United States,13 and the majority of the vehicles on the road are more than 6 years old! 14

Of course all of this seems to beg the question: when will autonomous cars start hitting the road? While the answer to that question may seem a long way off, with all of this rapidly changing technology, one thing seems certain: technology will eventually eliminate intoxicated driving on our roads!

by Patrick T. Barone &
Robert A. Andretz, Esq.

Patrick T. Barone is an adjunct professor at Cooley Law School where he teaches "Drunk Driving Law and Practice."  Mr. Barone is also the co-author of two books on DUI-related issues, including Defending Drinking Drivers (James Publishing), a well-known and highly respected multi-volume national legal treatise.  He is a frequent lecturer on trial practice and drunk driving defense tactics. He can be contacted on the web at: www.baronedefensefirm.com.

Endnotes

1. http://www.ft.com/cms/s/0/e5787fea-30e9-11e4-8313-00144feabdc0.html#axzz3CAzQUrIE (accessed September 2, 2014).

2.  JL Booker, End-position nystagmus as an indicator of ethanol intoxication, Science and Justice 2001: 41(2): 113-116 (2001).
3.  R. I. Hammoud, Passive Eye Monitoring:  Algorithms, Applications and Experiments, Springer Science & Business Media (February 1, 2008).
4.  Id.
5.  Id.
6.  Id.
7.  Nawrot, Disruption of Eye Movements by Ethanol Intoxication Affects Perception of Depth From Motion Parallax, Psychological Science, Vol15, No 12 (2004).
8.  Purves D, Augustine GJ, Fitzpatrick D, Neuroscience, 2nd ed (2001).
9.  Patent No. US5729619 A, http://www.google.com/patents/US5729619 (accessed September 2, 2014).
10.  Hammoud, supra at 15.
11.  Auto sales reach six-year high of 15.6 million vehicles sold, Ford F-Series takes the lead, http://www.nydailynews.com/autos/auto-sales-reach-six-yearhigh-demand-peaked-article-1.1567645 (accessed September 2, 2014).
12.  http://media.gm.com/media/us/en/gm/news.detail.html/content/Pages/news/us/en/2014/Jan/gmsales.html (accessed September 2, 2014).
13.  http://en.wikipedia.org/wiki/Passenger_vehicles_in_the_United_States (accessed September 2, 2014).
14.  Id.

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