Measuring Distraction: Methods & Techniques

I tend to drive 10-15 ++ above most posted limits on hiways and freeways. I have logged nearly 1 million miles of acutal driving at 10 - 15 miles above the posted limits (55,65,70 MPH) without a single accident and very few incidents (deer etc). Most of these miles have been durning day time hours, 70% or so. About 30% of them have been on snow or other incliment weather. So I'm saying I drive about 80 - 95 MPH when I can and I drive to conditions the rest of the time and have almost no problems, except speeding tickets. The reason I'm writing this is because I have always maintained that a good part of the reason I have had no accidents is because I HAVE to pay attention to the road! This is just an observation I have made over the years, based on the fact that when I'm driving the speed limit for whatever reason I tend to not pay attention very well. Nothing is happening, well not enough for me to constantly pay attention anyway. The traffic lanes are wide, and the signs are pretty good and I generally know where I'm going so I don't really have much to do but hang out and keep the vihicle going down the road when driving slow or within limits. I guess my question is, other than the speed differential between vihicles is there a corrilation between setting speed limits to low and higher traffic accident rates? chazmic1

The number of times I have been driving behind an individual who was holding a phone to their ear while making a left or right turn is alarming. More often than not the person attempts to make the turn with one hand, and at a very slow speed (annoying other drivers and tying up traffic in the intersection) - despite the slow speed they almost always drive their car into the oncoming traffic lane (too wide a turn) while others swerve to miss them. When horns are honked in anger they don't so much as turn their heads? Do people care that they are putting lives at risk? How can you drive safely with one hand, while putting your concentration into the conversation you are having? And if you're not putting concentration into the conversation - why take the call at all? Have we gone so far that phone calls come before personal safety? Would you use a table saw while on the phone? I think not. We need laws to protect our loved ones - the facts are already here!

The number of times I have been driving behind an individual who was holding a phone to their ear while making a left or right turn is alarming. More often than not the person attempts to make the turn with one hand, and at a very slow speed (annoying other drivers and tying up traffic in the intersection) - despite the slow speed they almost always drive their car into the oncoming traffic lane (too wide a turn) while others swerve to miss them. When horns are honked in anger they don't so much as turn their heads? Do people care that they are putting lives at risk? How can you drive safely with one hand, while putting your concentration into the conversation you are having? And if you're not putting concentration into the conversation - why take the call at all? Have we gone so far that phone calls come before personal safety? Would you use a table-saw while on the phone? I think not. We need laws to protect our loved ones - the facts are already here!

Wierwille and Tijerina (1998) using a narrative crash database from North Carolina were able to put together a simple regression model that relates eye glance behavior to crash rates. This model, although simple, is built upon actual crash data and reasonable assumptions. The model requires as input the following parameters:

• Average Glance Length
• Number of Glances, and
• Frequency of device use

The data for the fuel gage was present in the Wierwille and Tijerina article as were data on the frequency of using radio controls. I used additional data that we have gathered on-road over several years from a variety of studies and data that were present in other articles to generate a range representing the types of new devices that are coming onto the market. In addition to using these data for glance length and number of glances, I estimated that a typical frequency of use for such a device would be 20 times per week. This represents two times per commute trip and would probably be a reasonable estimate for a navigation system with traffic information or a mobile internet type of application. In contrast, the radio control use frequency was 56 times per week. From these data, the model predicted a crash rate of 7 to 32 times higher for the newer devices relative to the simple visual task of checking a fuel gage.

Reference
Wierwille, W.W.and Tijerina, L. (l998). Modelling the Relationship between Driver In-Vehicle Visual Demands And Accident Occurrence. In Vision in Vehicles VI. North Holland Press, Amsterdam.

In the world today, I have met people that can not chew gum and walk, however I have met people that can and do it quite well. Like anything some people have more ability than others when it comes with coordination and multitasking responsibly. Many argue that cell phones are the cause of people's lack of driving skills, I think they only amplify the issue that too many people do not know how to drive safely. Cell phones are a no more a problem than the passanger that is talking to the driver. The interaction is the same but the mode of delivery is different. If cell phones were required to have the ear piece and microphone that so many of them have, it would solve some of the problems we face. But we will always have those people that lack both common sence and decency to pull over for an important phone call that takes more attention to drive safely.

That's why they are called accidents. That is the most insane comment I've read. Are you smoking crack? I hope you get in a minor accident and get to pay your proposed $3,000 fine for the first 30 days of vehicel impoundment, then you hit some ice and hit someone from behind, not causing any bodily injuries, but some minor car damage, then get found at fault because you were the one behind the other person, then you can pay the $36,500 fine. moron.

I don't believe that all drivers should be lumped into one category and then compared to a technology they are using in their vehicle while driving. Each driver has a different driving ability. There have been numerous times when I have come up on someone while I was talking on the phone, and I noticed them going slow, or swerving back and forth. I commented to the person I was talking to that they were probably drunk, but then when I got next to them, they were on the phone. I've seen people who can't drive without a phone, let alone with one. A test should be developed for driving and talking on a phone. I took a motorcycle test and I have an 'm' on my license. I should take a phone test and get a 'p' on my license. Then, I would be allowed to drive and talk. i.e., Drive an obstacle course while answering detailed questions over your cell phone.

We don't need to test and measure and come up with neat ways to track cell phone use with regard to accidents. We all already know it's unsafe. (Stand up comics are already making jokes about it.) Why do we need to wait for a certain number of people to die or become seriously injured before we do something about it? It's called preventative measures. I myself have been on the road with other drivers who I thought were drunk or otherwise incapcitated only to find out while passing them (to get at a safe distance from them) that they were on a cell phone. And it's true, I've been near other horrible drivers who were not on a cell phone. But just because there are other distractions, it doesn't mean we shouldn't regulate one. Those people without common sense (too numerous for my taste) who engage in conversations on their phones while driving will only stop if they have a good reason to - i.e., a law. We've got to stop accidents before they happen. I personally don't want to die just because some idiot can't wait until they get home to gossip.

This paper points towards a promising direction of research, i.e. to develop devices to measure driver alertness. Computer vision techinques should be utilized to develop devices that can monitor driver gaze and maybe sound an alarm when the attention is shifted from the road for more than a specified amount of time. Our research group is developing methods based on a single camera to track gaze and identify head rotations. We currently classify rotation in all viewing directions, detect eye/mouth occlusion, detect eye blinking, and recover the 3D gaze of the eyes. Such research can help develop low cost devices that can prevent driver distraction by helping the driver realize when he/she is distracted. For more information on our research efforts, visit UCF Computer Vision Lab - Projects

Responsible driving must be the number one priority of all drivers. Unfortunately, those who drive with full attention to the road are decreasing and decreasing rapidly. Good drivers need help. We need laws that can give law enforcement the tools to curb the irresponsible behavior of so many drivers on the road today. Celluar phones have their place but NOT when being used by the driver of a moving vehicle. The weight of national agencies is needed now to require/encourage states to ban cellular phones AND loud stereo systems that make it impossible for drivers to hear sirens or to sense other vehicles around them.

The writer of the original comment is obviously a ba driver and should not have been issued a driver's license. Cell phones do occupy one hand. unless the phone is laid down. i have seen many people do right hand or left hand turns with only one hand without having anything in their other hand. I have seen people make slow turnsith out a cell phone. The cell phone is being blamed for a lot for which it shouldn't be. The positives far and away out weigh the negatives anytime. I have two cell phones in my car. and can choose to use or not to use them. And I have driven over a million miles without an accident.

The driver has responsibility. And government has responsibility also. government's responsibility is to not go crazy with over regulation nor over punishment. the punishment schedule suggested is outrageously harsh and unrealistic. Every driver needs to do a realistic assesment of their ability to drive before they get behind the wheel. being too tired or too distractable should cause the driver to not start out operating a vehicle. What is needed is public education on how to make that assessment. the same assessment needs to be done to the vehicle as well.

We don't truly know that cell phones cause accidents. We do know they save a lot of miles driving. Or hunting for a phone booth in an unsafe neighborhood (at any time of day or night!) Or calling emergency services when a few minutes might make the difference between life and death. It is certain that cell phones have saved far more lives than they have inconvenienced. Regulating them out of use is NUTS!

I have to have grave doubts as to the accuracy of such reports. And to their endless retelling and expansions? Like the fish that got away??? Most of the tests given up as proof deal with unrealistic "test conditions" Such as a fake car with movie screens around you and then measuring how fast you can flash your lights at a green square that suddenly appears. And then they only test a few people. And what would happen if someone with a cell phone did better than someone without??? The integrity of the methods of testing is severely in doubt.

It is not the technology that is the trouble. The technology as it is right now is perfectly fine. Improvements will happen naturally. But the big trouble that will not ever be corrected by technology, the part that cannot be manufactured, is the NUT BEHIND THE WHEEL. i do not scan everything all the time while i am driving. I have good peripheral vision and i use the senses i have developed in over a million miles without an accident.

A cell phone has its place in the hand of the responsible driver. We should encourage responsibility in every aspect of life. And not by government regulation. Not by restricting choices. Not by dictating foolish regulations based on at best anecdotal research. I thank god when i see someone using a cell phone. if i have an accident after I have passed them i hope they would make a call that might save my life or someone elses.

Reasonable? The number of glances? I can pick a cd out of a box. open the jewel case, pop the cd off the plastic hub, use my pinky to open the tray, put the cd in the tray, and press play all with no glances at all. And i rarely pick the wrong cd. Before i take a glance off the road i try to the best of my ability to make sure it is safe to do so. and i would rather take six glances at intervals at a cd than six glances at a fuel gauge. Changing a cd or a cassette may take six times as many glances as a fuel guage but that does not mean it is six times more dangerous. Such unsophisticated assumptions are what throw the whole driver distraction research studies right into the trash pile. Measuring arcane variables and saying they have a role in this subject is just plain foolishness.

There are many distractions that canc cause collisions or near ones for that matter. Most are due either to teen drivers or cell phone use. There too many teenagers that get into a car and when there are others with them, they get distracted easily and tend to pay less attention to what they are doing. The same goes for mobile phone users. When one hand is holding the phone, they tend to pay less attention to where or how they are driving. Most people tend to pay close attention when speaking on a phone and this is also true for mobile phones. Anyway, most reports and persons who think that they are authorities always say that it is the dialing procedure which causes more of a distraction when in fact it is the actual usage thereof. Most hospitals, gas stations, and airlines require mobile phones to be turned off, and some other electronic devices for that matter, and it should not be any different than on the highway. After this, the next problem would be passing laws to limit the number of passengers that a minor may transport, even though aside from the use of mobile phones, that is also still a big problem.

Consider this familiar scenario: Bob is traveling at 55 mph on the interstate. Paul is traveling at 58 mph and is catching up to Bob. Bill is traveling at 75 and is catching up to both of them. Paul decides to change lanes to pass Bob but does not realize how fast Bill is approaching him. When Paul pulls out into the left lane, Bill rearends him. Bill needs to understand the "burden" of his speed. With a 1.6 second perception reaction time and a drag factor of 0.70, it will take him 444.41 feet to slide to a stop. With the same variables, it will take Paul 296.61 feet to stop. One problem is that Paul does not appreciate how much faster Bill is traveling. Therefore, he pulls out in front of him. A second problem is that Bill does not recognize the possibility that Paul might pull out in front of him. Neither of them is driving defensively.

Barry states that he feels cell phones are receiving undue criticism. Sure, Barry, people are distracted inserting tapes and CD's, fiddling with coffee mugs, putting on make-up, etc. A cell phone up to ones face is just so obvious. The position alone impares peripheral vision and takes a hand off the wheel. At least the make-up and CD can wait until a turn is made (not that I condone excessive attention to any of these other devices, etc.), however, people feel less compelled to drop the phone and interupt their phone conversation to make that same turn. And, I've seen plenty of these apes jump curbs, swerve wide, or near miss other cars and pedestrians. They also simply impede traffic flow by being overly cautious with distraction. When people can't accept responsibility for their actions, it's time to regulate them. I'm not a fan of regs, but when my safety is concerned, I say bring on the regs and fines. Hands-free only. First time offense warrants a steep fine. Second offense disconnects and disqualifies the driver from wireless service. The wireless companies should embrace hands-free cause it will encourage the mindless babblers to talk for many more minutes. Hands-free regs would bring on a huge stock jump for the wireless industry. They should lobby to have themselves regulated so they can enjoy the hand-free installation boom.

Your statement that a driver's primary task is driving is absolutely correct. Any distraction from his primary task will add risk. In a perfect driving situation, we would not have any unnecessary distractions. No cell phones, navigation systems, daytime running lights, radio/CD players, etc. Obviously a "perfect driving situation" rarely or never exists. However we must reduce these distractions to a minimum. Would we allow commercial airline pilots to be as distracted as an automobile driver ? Absolutely not !

Alternatives to Near Misses: Braking Time & Unsafe Distances

If a long period of time is not practical for the evaluation, then a short duration on-road evaluation in an instrumented vehicle or a driving simulator could be used. The data from such an evaluation, however, include the effects of learning to use both the vehicle and the in-vehicle ITS, of being watched, and of performing contrived driving scenarios. For simulators, there are also fidelity issues to consider. Data from this method include: obstacle avoidance and lane maintenance. Obstacle avoidance is measured in two ways: braking time and occurrence of unsafe distances. Olson and Sivak (1986) measured the time from the first sighting of an obstacle until the accelerator was released and the driver contacted the brake. Their data were collected in an instrumented vehicle driven on a two-lane rural road. Drory (1985) used the same measure in a simulator to evaluate the effects of different types of secondary tasks. Burger, Smith, Queen, and Slack (1977) used the brake reaction time distance between the cohort vehicle and the subject driver's vehicle. In addition they also calculated the minimum area surrounding a vehicle that should have been clear of other vehicles at the initiation of a specific maneuver and through the completion of the maneuver. This measure is similar to near misses described previously. To simplify the analysis in a later study, Burger, Mulholland, Smith, Sharkey, and Bardales (1980) used 60-foot criterion for gaps during lane changes. More recently, Korteling (1994) used car-following performance distance. In a series of on-road tests at Veridian, vehicle decelerations greater than 0.4 g were used to indicate unsafe following behavior.

Measuring Lane Maintenance

The risk of lane infringement and run-off-the-road accidents has been inferred from lane exceedances. This measure has already been used to evaluate in-vehicle ITS. For example, based on findings in a study of the safety aspects of Cathode Ray Tube (CRT) touch panel controls in automobiles, Zwahlen, Adams, and DeBald (1988) stated, "the probabilities of lane exceedence during the operation of a CRT touch panel (driving at 40 mph, along a straight, level, smooth roadway; under ideal driving conditions) are 3% and 15% for lane widths of 12 feet and 10 feet, respectively, which are unacceptable from a driver safety point of view." Summala, Nieminen, and Punto (1996) used lane exceedances to evaluate location of a display in an automobile cockpit. Imbeau, Wierwille, Wolf, and Chun (1989) reported that the variance of lane deviation increased if drivers performed a display reading task. The data from both these studies were collected in a driving simulator. A similar measure, Time-to-Line-Crossing (TLC), was developed to enhance preview-predictor models of human driving performance. TLC equals the time for the vehicle to reach either edge of the driving lane. It is calculated from lateral lane position, the heading angle, vehicle speed, and commanded steering angle (Godthelp, Milgram, and Blaauw, 1984). Godthelp (1986) reported, based on field study data, that TLC described anticipatory steering action during curve driving.

Eye Glance Measures

When data can be collected in only a single car and only on the driver (not the vehicle), glance behavior has been used to infer safety impacts. Glance duration has long been used to evaluate driver performance. For example, in an early study, Mourant and Rockwell (1970) analyzed the glance behavior of eight drivers traveling at 50 mph on an expressway. As the route became more familiar, drivers increased glances to the right edge marker and horizon. While following a car, drivers glanced more often at lane markers. Burger, Beggs, Smith, and Wulfeck (1974) discussed the importance of considering long-duration glances away from the forward scene during safety evaluations and suggested using 2.00 sec as the definition of a long-duration glance. In research more relevant to evaluating the safety impacts of in-vehicle systems, Zwahlen, Adams, and DeBald (1988), cited previously, investigated the eye scanning behavior when driving in a straight path while operating a simulated CRT touch panel display (radio and climate controls). Similarly, Imbeau, Wierwille, Wolf, and Chun (1989), also cited previously, used time glancing at a display to evaluate instrument panel lighting in automobiles. Not unexpectedly, higher complexity messages were associated with significantly longer (+0.05s more) glance times. Kurokawa and Wierwille (1991) found, in a study of control label abbreviation effects, that labels could produce small but reliable reductions in number of glances to the instrument panel. Fairclough, Ashby, and Parkes (1993) used glance duration to calculate the percentage of time that drivers looked at navigation information (a paper map versus an LCD text display), roadway ahead, rear view mirror, dashboard, left-wing mirror, right-wing mirror, left window, and right window. Data were collected in an instrumented vehicle driven on British roads. The authors concluded that this "measure proved sensitive enough to (a) differentiate between the paper map and the LCD/text display and (b) detect associated changes with regard to other areas of the visual scene" (p. 248). These authors warned, however, that reduction in glance durations might reflect the drivers' strategy to cope with the amount and legibility of the paper map. These authors also used glance duration and frequency to compare two in-vehicle route guidance systems. The data were collected from 23 subjects driving an instrumented vehicle in Germany. The data indicate, "as glance frequency to the navigation display increases, the number of glances to the dashboard, rear-view mirror and the left-wing mirror all show a significant decrease" (p. 251). Based on these results, the authors concluded, "Glance duration appears to be more sensitive to the difficulty of information update. Glance frequency represents the amount of. "Visual checking behavior" (p. 251).

Differences Between Simulator and On-Road Driver Performance

Olson and Sivak (1984), cited previously, used both laboratory and field studies to evaluate the effects of glare from rearview mirrors on driver performance. The laboratory study implied a reduction in seeing distance of 50% but, in the field study, the loss even at the highest glare level was only 15%. Korteling (1990) used the RT of correct responses and error percentages to compare laboratory, stationary, and on-road driving performance. RTs were significantly longer in on-road driving than in the laboratory.

Summary

If near misses cannot be collected then the following measures have been used to infer safety impact: braking time, distance to following vehicle, distance to obstacle, vehicle deceleration, probability of lane exceedence, and glance duration. If comparative data (i.e., in-vehicle ITS present versus absent) cannot be collected, then the following criteria have been used to infer safety impact:

• Braking time less than the time required to brake prior to hitting the obstacle
• Distance to following vehicle, less than braking distance
• Distance to obstacle, less than braking distance
• Vehicle deceleration, greater than 0.4 g
• Probability of lane exceedence, less than 3% for 12 foot lane and 15% for 10 foot lane
• Glance duration, less than or equal to 2 seconds

The type of question you were asked raises the issue in my mind of whether the safety impact of various in-vehicle technologies can be evaluated based on comparison to the safety impact of somewhat comparable non-technology tasks. These are tasks that generally seem to be acceptable safety risks, such as talking to passengers or adjusting the radio. What do you think of this idea as a way to set a criterion level of acceptable safety? The impact measures can be some of the ones you listed but applied to specific baselines of driver performance doing societally acceptable tasks, not just with and without an ITS device.

In all science, measurement is the process of assigning numbers to objects in a systematic manner. The scientist interested in measurement must always answer two questions:

1. (representation problem) How is the assignment of numbers to objects justified?
2. (uniqueness problem) To what degree is this assignment unique?

Reliability is an index of the consistency of a measure and addresses the representation problem. Validity is an index of the truth of a measure and is related to the uniqueness problem. Good measures are both reliable and valid.

Good research must also be generalizable. This means that results can correctly be applied to real-world systems. Generalizability depends upon three factors: subject representativeness, variable representativeness, and setting representativeness (see Kantowitz, 1992 for detailed explanations of these terms.) We can't guarantee that a measure, even if reliable and valid, will work properly unless it is observed in a research setting that is generalizable.

Without getting bogged down in technical details (see Kantowitz, 1992 if you want to slog through details), the best way to select a measure that will work is to be guided by theory. It is poor science to select a measure just because it is easy to obtain. It is almost impossible to select a single measure that captures all the essential characteristics of a complex system, such as a driver in a vehicle. Theory must be used to select a set of measures that are useful and appropriate.

Selecting Measures for Driver Distraction

It might seem that the best way to measure driver distraction would be simply to ask drivers if they were distracted by some event. This is called obtaining a subjective opinion. We can make this process appear even more scientific by asking the driver to rate (perhaps on a five-point scale from 1-5) how distracted they were. This is called a rating scale. Unfortunately, people are not always able to give subjective ratings in a consistent manner (see Nygren, 1991). Even with a lot of fancy statistical treatments, it can be difficult to interpret subjective ratings. They are used because they are easy to obtain and because sometimes they can be correlated with better measures of distraction.

The best measures are objective rather than subjective. This includes measures of how the vehicle is located on the roadway, how hard the driver is pushing on the brake pedal, and how long it takes the driver to react to a signal. Physiological measures are also objective but they are best for determining long-term states of the driver, such as fatigue, rather than specific reactions to particular signals.

Since distractions are related to driver attention, theories of attention can help us select the best measures. An important class of measures require the driver to perform another task, called a secondary task, while driving (Kantowitz & Simsek, 2000). If the driver is distracted, there is less attention available to perform the secondary task. So objective performance on the secondary task can be interpreted, using a theory or model of attention, as an index of driver distraction. For example, a secondary task might require a driver to push a button on the steering wheel when an auditory tone is heard inside the vehicle. The time from the onset of this tone until the driver pushes the button, called reaction time, would be a measure of distraction. If reaction time is high, the driver was distracted when the tone came on. If reaction time is low with a rapid response to the tone, we can rule out distraction.

However, there is no unique secondary task for measuring driver distraction. Many secondary tasks have been studied and several are useful (Kantowitz & Simsek, 2000). Some typical secondary tasks would include memorizing telephone numbers, doing mental arithmetic and pressing buttons when signals are presented inside the vehicle. But most of these secondary tasks are scored either by reaction time or by proportion of correct responses. So the best measures of driver distraction are time and/or correct responses provided a secondary task has been selected that meets the criteria explained in the first section of this answer.

Conclusion

There is no single best measure of driver distraction. Objective measures are better than subjective measures. Secondary-task measures of driver distraction offer the best opportunity for success because they can be related to theories of attention. Even so, it is not simple to select the most appropriate secondary task.

References

Kantowitz, B.H. (1992) Selecting measures for human factors research. Human Factors, 34, 387-398.

Kantowitz, B.H. & Simsek, O. (2000, in press) Secondary-task measures of driver workload. In P. Hancock & P. Desmond (Eds) Stress, workload and fatigue. Mahwah, NJ: Erlbaum.

Nygren, T.E. (1991) Psychometric properties of subjective workload measurement techniques: Implications for their use in the assessment of perceived mental workload. Human Factors, 33, 17-34.

Why do we need 'tests' etc to see if cell phones are dangerous? (to give some 'panel' a job?) COMMON SENSE and observation gives the rest of us the answer as to 'is cell phone use while driving, dangerous?' Duh - wake up and look around at the cars in traffic along side of you and observe their driving while they are on the phone! Driving needs your FULL ATTENTION at all times!!!! Cars should be designed so that cell phones only work when the car is in 'park' thereby letting the driver give his full attention to the conversation on the phone (or map search or whatever it is that would otherwise distract the driver) while he is safely parked along side of the road or pulled into a parking lot, etc. and thereby making the roads SAFER FOR THE REST OF US!!

How can we get a copy of that report?

I don't know what branch of the government you work for - my guess is the IRS - it is certainly not DOT. I rather doubt that you can back up your claim that cell phones have saved a lot more lives than they have "inconvenienced." (By the way, I think inconvenience is an interesting euphamism for death.)

This would be the easiest to find: Haigney, D. and Taylor, R., 1999. “Mobile phone use while driving: Phone operation vs. vehicle transmission.” Ergonomics Society annual conference, Contemporary Ergonomics, 78-82