Criteria for a Driver Distraction Definition

Criteria for a Driver Distraction Definition
                                     Adapted from Savino (2009, pp. 17-23)

Please select “Yes” or “No” below whether you agree or not that the criterion shown should apply to a driver
   distraction definition. Explanation of each criterion is given in the Endnotes as indicated.

Measurement Process

1 Does the definition suggest a single and complete measurement procedure?1 ___Yes ___No
2 If so, is it easy to measure?2 ___Yes ___No
3 Does the measurement produce repeatable data?3 ___Yes ___No
4 Is the definition general enough that it can be used for driver distraction measured in simulator testing as well
    as field testing?4 ___Yes ___No
5 Does the definition have a single interpretation?5 ___Yes ___No
6 Can the results of data collected using the definition be easily represented graphically?6 ___Yes ___No
7 Is the definition applicable to engineering procedures and calculations?7 ___Yes ___No
8 Is it applicable to international driving conditions, driving infrastructure and vehicles?8 ___Yes ___No
9 Is the definition or at least the terms in it frequently used in the literature?9 ___Yes ___No
10 Consistency within the set of similar words used in the definition?10 ___Yes ___No
11 Avoids circularity?11 ___Yes ___No
12 Defines every key word in definition?12 ___Yes ___No
13 Key words prioritized in definition?13 ___Yes ___No
14 Written in simple, clear, concise English?14 ___Yes ___No
15 Uses SI units where appropriate?15 ___Yes ___No
16 Easily translatable from English to non-English languages?16 ___Yes ___No
Specify any other criteria you feel a definition should meet:
17 _______________________________________________________________

18 _______________________________________________________________

19 _______________________________________________________________

20 _______________________________________________________________

21 _______________________________________________________________

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Broadbent, D.E. (1979). Is a fatigue test now possible? Ergonomics 22, pp. 1227- 1290.
Hancock, P. A. and W. B. Verwey (1997). "Fatigue, workload and adaptive driver systems." Accident Analysis &
 Prevention 29(4): 495-506.
Landau, S. I. (2001). Dictionaries: The art and craft of lexicography.Cambridge, England: Cambridge University Press.
Muscio, B. (1921). Is a fatigue test possible? British Journal of Psychology. General Section, 12(1), 31-46. doi:
Savino, M.R. (2009). Standardized Names and Definitions for Driving Performance Measures (unpublished Master’s
  thesis), Medford, MA: Tufts University, pps. 17-23.

Endnotes [text in italics is quoted from Savino (2009)]

1 The definition must completely explain all aspects of the measurement procedure, from the time measurement begins
   until measurement is concluded. For example, Blanco, Hankey, & Chestnut (2005) defined lane departure "as the time
   from when the tire came into contact with the lane marker until the tire was no longer in contact with the lane marker
   and the vehicle was in the correct lane”. This definition offers a single and complete measurement procedure from
   measurement beginning (“tire came into contact with the lane marker”) until measurement end (“until the tire was no
   longer in contact with the lane marker and the vehicle was in the correct lane”). Conversely, the following lane
   departure definition, also from Blanco, Hankey, & Chestnut (2005), does not offer a complete 18 measurement
   procedure: "Defined as when the vehicle’s tire came into contact with the lane marker." Although the definition offers a
   clear point at which to begin measurement (“when the vehicle’s tire came into contact with the lane marker”), the
   definition does not state any point at which measurement is to end.
2 Practically speaking, ease of measurement is one of the most important criteria for a good driving performance
   definition. If a definition is not easy to measure, it will see limited use to researchers. Ease of measurement considers
   current, comprehensive measurement tools, such as video cameras, and on-board sensors frequently found on
   contemporary driving simulators and instrumented vehicles. Measurement ease also considers convenience for
   researchers: For example, if a researcher is measuring a lane departure, it might be more convenient to reference the
   departure in terms of tire contacting lane striping compared to vehicle body contacting the plane of the lane striping
   because the tire/striping contact is a directly visible intersection, as opposed to an indirect contact, such as a wing
   mirror over the lane striping.
3 Repeatability means that the findings are consistent if measurement were repeated. If the measurement were not
   repeatable, then there is potential that different experimenters may interpret the definition differently, therefore
   producing differing results. As an example of a repeatable definition, SAE J1761 3.155 defines headway as the “time
   between which the leading surfaces of two consecutive vehicles pass the same location along a roadway.” It is clear
   from the definition that headway is always measured from the leading surface of two consecutive vehicles traveling on
   the same roadway. The leading surface of vehicles is a point that will remain consistent and has only one
   interpretation. Conversely, the following definition for time headway is open to numerous interpretations: “Time
   headway - defined as the distance expressed in time between two vehicles” (Hakan 2000). No specific measurement
   reference points on the vehicles are specified in this definition, which leaves this definition open to many different
4 The more versatile the measurement procedure, the more useful it will be to any study. Human factors specialists
   conduct testing in both driving simulators and on the road in instrumented test vehicles. Because these two types of
   testing are popular, one definition that could be applied to both contexts would be ideal. For example, the location of
   the center of gravity is readily determined on a simulated vehicle but requires much more effort for a real vehicle.
5 Measure name clearly describes phenomenon in question. There is no ambiguity describing any driving performance
6 One advantage to summarizing data pictorially or graphically is that data can often be concisely summarized. Measures
   with definitions convenient for graphing have the potential to assist researchers. A second advantage is that pictures

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and graphs generally transcend language, providing readily accessible data to individuals whose native language is
   different from the language used in the research.
7 Proposed measurement definitions must be useful for carrying out engineering procedures and conducting calculations.
8 Needing consideration are left versus right-hand drive, differences in lane widths and shoulders, differences in lane
   markings (line width, solid versus dashed) and their regulatory implications, other differences due to traffic rules,
   customs and other characteristics.
9 Defined as measurement term being used at least three times in selected literature.
10 In order to create commonality between measurement terms across all measure categories, it is preferred to use
   common terminology. For example, the measure name “lane change” is consistent with the measure name, “lane
   departure,” because both share the common term “lane.”
11 Forms of circularity are illustrated below in terms of driver distraction definitions.
  The first two illustrations are adapted from Landau (2001), as quoted by Savino (2009, p. 14).

   11.1. Defines A in terms of B and B in terms of A:

                   LEXICAL UNIT                     DEFINITIONS
        A          Driver distraction               The state of a distracted driver
        B          Distracted driver                A driver who experiences distraction
        A          Distraction                      Inattention
        B          Inattention                      Distraction

   11.2. Defines A in terms of A but never define A, as illustrated here:

                   LEXICAL UNIT                     DEFINITIONS
        A          Distraction                      The state of being distracted.

        “Distracted” is then nowhere defined in the rest of the publication.

   Many definitions of driver distraction in the literature tend to be more subtlely circular, or even a “Catch-22”, tautology,
   contradiction, paradox, or conundrum. Some further artificial examples to illustrate the point are given:

   11.3. To define driver distraction, we need to be able to measure it, and to measure it we need a valid and reliable
      assessment tool. However, we cannot construct a tool with knowing what it is precisely that we wish to measure.
      [paradox, conundrum]
      [Note: Example adapted from the definition of fatigue as given by Music (1921), Hancock and Verwe (1997), and
      Broadbent (1979).]

   11.4. Driver distraction is defined as arising from any activity that is not driving-related that causes the driver to shift
      attention away from the driving task in the 5 seconds before a critical incident. A shift of attention away from the
      driving task is defined as driver distraction. [circular]
   11.5. Driver distraction is one form of inattention in which some trigger event compelled the driver's shifting of attention
      away from the driving task. The presence of a triggering event distinguishes a distracted driver from one who is
      simply inattentive. [contradiction]
12 Readers have a right to expect that if they do not know the meaning of a word used in a technical definition, they can
   find that word defined later in the paper. If they do not find the word, different readers will adopt their own internal
   subjective understanding of the word, which may be quite different for different readers.
13 Self-evident.
14 Simple: Avoid including difficult words in definitions of simpler words’ is a traditional rule that seems to make sense, but
   like so many lexicographic rules it is often impossible to apply. Concise: Dictionary definitions should not waste words.

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The art of defining depends not only on the ability to analyze and understand what the words mean, but equally on the
   ability to express such meanings succinctly.
15 The International System of Units (abbreviated SI from the French Système international d'unités) is the modern form
   of the measurement system. It is the world's most widely used system of units, both in everyday commerce and in
   science. Since human factors research is scientific in nature, all measures should be expressed in SI units.
16 Self-evident.

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