Figure 1.1: A compressed video image from the 100-Car Study data. The driver’s face (upper left quadrant) is distorted to protect the driver’s identity. The lower right quadrant is split with the left-side (top) and the rear (bottom) views; photographic montage illustrating views from the in-vehicle cameras.

Figure 1.2: The main DAS unit mounted under the “package shelf” of the trunk; photograph of the main data acquisition system (DAS) unit mounted under the “package shelf” of the trunk.

Figure 1.3: Doppler radar antenna mounted on the front of a vehicle. Photograph of the Doppler radar antenna mounted on the front of a vehicle, covered by one of the plastic license plates used for this study.

Figure 1.4: The incident pushbutton box mounted above the rear-view mirror; Photograph of the incident push button box mounted above the rearview mirror. The portion on the right contains the driver face and left road view camera hidden by a smoked Plexiglas cover.

Figure 1.5: Flow chart of the data reduction process; block diagram illustrating the data reduction process.

Figure 1.6: Trigger criteria settings for Phase II and Phase IV using the distribution of valid events. Graphical depiction of the distribution of valid critical incidents and the distribution of invalid critical incidents; note that this distribution and criterion placement is unique for each trigger type.

Figure 1.7: Incident event frequency; scatter plot showing the frequency of each vehicle’s involvement in crash, near-crash, and incident events versus the number of baseline epochs selected for each vehicle.

Figure 2.1: Inattention-based events 1; bar chart illustrating the percentage of the total number of crashes and near-crashes identified in the 100-Car Study and the percentage of the total number of baseline epochs in which these types of inattention (secondary task, driving-related inattention, secondary task plus non-specific eyeglance, drowsiness, non-specific eyeglance, secondary task plus driving-related inattention, driving-related inattention plus non-specific eyeglance, drowsiness plus non-specific eyeglance, driving-related inattention plus drowsiness, secondary task plus driving-related inattention plus non-specific eyeglance, or secondary task plus non-specific eyeglance plus drowsiness) were identified as a contributing factor (N = 69 crashes, 761 near-crashes, and 4,977 baseline epochs).

Figure 2.2: Inattention based events 2; bar chart illustrating the percentage of crashes and near-crashes in which these types of inattention (secondary task, drowsiness, driving-related inattention, secondary task plus driving-related inattention, secondary task plus drowsiness, driving-related inattention plus drowsiness) were identified as a contributing factor (N = 69 crashes, 761 near-crashes, and 19,827 baseline epochs).

Figure 3.1: Lighting; bar chart illustrating the percentage of secondary-task-related, drowsiness-related, and total baseline epochs for the different lighting levels (dawn, daylight, dusk, darkness lighted, and darkness not lighted) observed.

Figure 3.2: Weather; bar chart illustrating the percentage of secondary-task-related, drowsiness-related, and total baseline epochs for each type of weather (clear, rain, misting, snowing, sleeting, fog, and other).

Figure 3.3: Roadway type; bar chart illustrating the Percentage of secondary-task-related, drowsiness-related, and total baseline epochs by type of roadway (divided, not divided, one-way, and no lanes).

Figure 3.4: Roadway alignment; bar chart illustrating the percentage of secondary-task-related, drowsiness-related, and total baseline epochs by type of roadway alignment (straight level, curve level, straight grade, curve grade, straight hillcrest, curve hillcrest, and other).

Figure 3.5: Traffic density; bar chart illustrating the percentage of secondary-task-related, drowsiness-related, and total baseline epochs by type of traffic density (free flow, restricted flow, stable flow, unstable flow, flow is unstable, and forced flow).

Figure 3.6: Surface conditions; bar chart illustrating the percentage of secondary-task-, drowsiness-related and total baseline epochs for all surface conditions (dry, wet, snowy, icy, muddy).

Figure 3.7: Traffic control; bar chart illustrating the percentage of secondary-task-related, drowsiness-related, and total number of baseline epochs for each type of traffic control device (no traffic control, officer or watchman, yield, stop sign, traffic signal, one-way sign, no passing sign, slow or warning, railroad crossing, traffic lanes marked, and other).

Figure 3.8: Junction; bar chart illustrating the percentage of secondary-task-related, drowsiness-related, and total number of baseline epochs for each relation to junction (non-junction, intersection, intersection-related, interchange, alley or driveway, entrance/exit ramp, rail grade crossing, parking lot, an other).

Figure 4.1: Frequency; graph illustrating the frequency of inattention-related crashes and near-crashes by driver in order from low frequency to high frequency (mean 3.6).

Figure 4.2: Involvement in crashes; bar chart illustrating the average age of the high- and low-involvement drivers in inattention-related crashes and near-crashes.

Figure 4.3: Age group; bar chart illustrating the frequency of inattention-related crashes and near-crashes for each age group by involvement group.

Figure 4.4: Gender; bar chart illustrating the gender breakdown of high- and low-involvement drivers.

Figure 4.5: Driving experience; bar chart illustrating the average years of driving experience for drivers with high- and low-involvement in inattention-related crashes and near-crashes.

Figure 4.6: Involvement in traffic violations; bar chart illustrating the number of self-reported involvement in traffic violations and collisions for 5 years prior to the onset of the 100-Car Study.

Figure 4.7: Personality scores - extraversion; bar chart illustrating the personality scores for the extraversion scale demonstrating significant differences between drivers with high and low involvement in inattention-related crashes and near-crashes.

Figure 4.8: Personality scores - openness; bar chart illustrating the personality scores for the openness to experience scale demonstrating significant differences between drivers with high and low involvement in inattention-related crashes and near-crashes.

Figure 4.9: Personality scores – agreeableness; bar chart illustrating the personality scores for the agreeableness scale demonstrating significant differences between drivers with high and low involvement in inattention-related crashes and near-crashes.

Figure 4.10: Personality scores – conscientiousness; bar chart illustrating the personality scores for the conscientiousness scale demonstrating significant differences between drivers with high and low involvement in inattention-related crashes and near-crashes.

Figure 4.11: Frequency of inattention-related crashes; scatter diagram illustrating the frequency of inattention-related crashes and near-crashes by driver in order for Low, Moderate, and High frequency.

Figure 5.1: Frequency distribution of the number of inattention-related baseline epochs; graph illustrating the frequency distribution of the number of inattention-related baseline epochs that each driver was involved (N = 101). Note: Subjects were sorted by frequency of involvement to allow the reader to see the range of values.

Figure 6.1: Drivers’ eyes off roadway; bar chart illustrating the total mean time drivers’ eyes were off the forward roadway during the 6-second segment of time prior to the onset of the conflict.

Figure 6.2: Glances away from the forward roadway; bar chart illustrating the mean number of glances away from the forward roadway occurring during 5 seconds prior and 1 second after the onset of the conflict or during a 6-second baseline driving epoch.

Figure 6.3: Length of longest glance; bar chart illustrating the mean length of longest glance initiated during the 5 seconds prior and 1 second after the onset of the conflict.

Figure 6.4: Depiction of visual angle; drawing showing a depiction of degrees of visual angle from center forward that objects in the cockpit of an automobile are generally located.

Figure 6.5: Longest glance away from roadway; bar chart illustrating the percentage of the location of the longest glance away from the forward roadway by severity.

Figure C-1. Drowsiness Scale; a diagram showing the observer rating of drowsiness scale where not drowsy is equal to 0 and extremely drowsy is equal to 100.