Cover Image

Not for Sale



View/Hide Left Panel
Click for next page ( 88


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 87
A P P E N D I X B Project 5 Data Dictionary Coding Key for RDCWS Alerts be certain what happened during that portion of the clip. If one eye location could be determined and the other eye's LDWS and CSWS alerts were coded using different criteria; location could not, location was still coded. Reviewers were driver behavior, however, was rated in the same way for each confident in coding eye position when only one eye could be set of alerts. Those criteria are listed first below. Specific cat- seen because normally eyes move in parallel. If the driver's egories regarding scenario details were different for each sys- eyes were away before the alert and in transition at the time of tem. Each of the scenario coding keys is described after the the alert, the last forward glance code reflected where they driver behavior key. were looking at the time of the alert, not where they had pre- viously been looking. For more details on eye location, see the Driver Behaviors information on Location of Eyes at Time of Alert. The criteria for classifying a glance as a specific location are the same as Location of the driver's eyes during the last nonforward glance the criteria for eye location at the time of the alert. and time from the last nonforward glance. If the driver's eyes were on the forward scene at the moment 0 = Always looking forward at the forward scene. of the alert but had looked away during some portion of the 1 = Left outside mirror or window. clip before the alert, this location was recorded. Reviewers also 2 = Looking over left shoulder. recorded the amount of time between when the driver's gaze 3 = Right outside mirror or window. began to return to the forward scene and the moment of the 4 = Looking over right shoulder. alert, according to the driver-vehicle interface (DVI) display 5 = Interior rearview mirror. on the computer monitor. The actual moment of the alert was 6 = Head down, looking at instrument panel or lap area. not counted; the time represents the time between the change 7 = Head down, looking at center console area. (Console in gaze and the alert. Time was recorded in 10ths of seconds. means the area where the stereo, thermostat, and clock are If the driver was always looking forward, the time from the last nonforward glance was left null because that category was not located.) 8 = Driver wearing sunglasses or glasses with glare. (Glare pro- applicable. If the driver was looking away 0.1 s before the alert and then was looking forward at the time of the alert, the time hibited the ability to classify where the eyes were looking.) 9 = Cannot accurately evaluate eye location. (This was coded from the last nonforward glance was recorded as 0. If the eyes were not visible, typically because of glare, for any portion of as 9 when reviewers were unsure of the eye position or clas- the clip, the location was coded as 9 because one could not be sification within a reasonable level of confidence, although certain there was not a glance away. The only exception to this not because of glasses. Typically, reviewers could see the rule is when reviewers could not see the driver's eyes and then actual eye but could not determine where the gaze was the eyes became visible so that reviewers could see the eyes directed. Eyes in transition were often coded as 9 because it and there was a glance away before the alert. This situation was unclear where the driver's gaze was at that particular negates the fact that reviewers could not see the eyes at the moment.) beginning of the clip, because there was a nonforward glance 10 = Other. (For example, the driver may clearly be looking after the portion during which the eyes were unclassifiable. If at the passenger side floor. When a glance was coded as other, the eyes were unclassifiable again, before the alert but after the the location was noted in the notes section. The most com- glance, the eyes were coded as 9 because reviewers could not mon position recorded as other was the rearview mirror.) 87

OCR for page 87
88 Location of Eyes at Time of Alert but reviewers believed that they could confidently identify the location of the drivers' eyes. In these instances, eye loca- This category was coded at the actual time of the alert. Eye loca- tion was recorded.) tion was coded by what reviewers could see of the driver's eyes 9 = Cannot accurately evaluate eye location. (The code 9 at the time of the alert, even if they could not see the eyes before was chosen when reviewers were unsure of the eye posi- the alert. Reviewers coded the location of the driver's eyes even tion or classification within a reasonable level of confi- if they could see only one eye because it was assumed that the dence but not because of glasses. Typically, reviewers driver's eyes moved in parallel. Because of the absence of an eye- could see the actual eye but could not determine where tracking camera and the limitations of the face camera, there the gaze was directed. Eyes in transition were often coded was often some ambiguity about where the drivers were look- as 9 because it was unclear where the driver's gaze was at ing. Reviewers needed to be confident in the location of the that particular moment.) driver's eyes to code as a specific location. In many instances, 10 = Other. (For example, the driver may clearly be looking reviewers were confident that the driver's eyes were not looking at the passenger side floor. When a glance was coded as other, forward but could not tell specifically where the eyes were look- the location was noted in the notes section. The most com- ing. These instances were coded as 9s. One such example is when mon position recorded as other was the rearview mirror.) the driver appeared to be looking at the camera. In this situa- tion, it was difficult to determine if the driver was looking at the camera intentionally, glancing out the corner, or looking Eyes on Task at Time of Alert slightly out the left window; therefore, it was coded as 9. 0 = No. (The classification of no was used only when review- Another example is when the driver was looking toward the ers could confidently determine that the driver's eyes were curve that elicited the alert. The exact location of the driver's off the task of driving at the time of the alert [e.g., the driver eyes could not be determined in these instances, although a was looking at a friend or the stereo system].) notation was made in the notes field. The determination of 1= Yes. (The classification of yes does not mean looking whether glances were still forward or if they were glances away forward; it means that the driver's eyes were on the task of was also difficult and subjective. Reviewers agreed on an area or driving. Looking at the instrument panel, for example, was box they considered to be looking forward; this allowed for considered on task.) slight glances but even many scans across the forward scene 2 = Cannot determine (For instance, the driver was wear- were considered glances away. This process defined looking for- ing glasses with glare or reviewers could not see the driver's ward narrowly and essentially as meaning straight forward. eyes for some other reason. This classification was also Glances toward the right of the forward scene, the right area of used when reviewers could not tell if the eye location was the windshield, were glances away and were coded as 9s. on task. For instance, the driver was looking out the win- dow [e.g., toward a curve in the road], but it was unclear 0 = Looking forward at forward scene. (Looking forward whether the driver was looking at the road and traffic or at included looking at the head-up display [HUD].) a fancy building that was distracting the driver's attention. 1 = Left outside mirror or window. In any case, reviewers did not know whether the driver was 2 = Looking over left shoulder. (The driver's gaze needed on task.) to look over the driver's shoulder but the driver's chin did not necessarily need to cross over the driver's shoulder.) Eyes in Transition 3 = Right outside mirror or window. 4 = Looking over right shoulder. (The driver's gaze needed To classify the eyes as in transition, the driver's eyes must to look over the driver's shoulder but the driver's chin did have been in transition at the time of the alert and must have not necessarily need to cross over the driver's shoulder.) started the transition at least 0.1 s before the alert. The eyes 5 = Interior rearview mirror. could not be at the beginning of a transition or the end of one; 6 = Head down, looking at instrument panel or lap area. they must have been in the transition at the time of the alert. (Looking at the HUD was not considered part of the instru- ment panel.) 0 = No. 7 = Head down, looking at center console area. (Console 1 = Yes, toward forward scene. means the area where the stereo, thermostat, and clock 2 = Yes, away from forward scene. are located.) 3 = Cannot tell. (Cannot tell was selected when the driver 8 = Driver wearing sunglasses or glasses with glare. (The was wearing sunglasses or reviewers could not see the driver's glare prohibited the ability to classify where the eyes were eyes for some other reason; therefore, researchers were looking. In some instances, drivers were wearing sunglasses, uncertain whether the eyes were in transition.)

OCR for page 87
89 Visual Response to Alert and Time Startle Response to Visual Response This was subjective and the classification as such was often If the driver initiated a visual response to the alert, review- hotly debated. The driver had to be visibly rattled. The driver's ers coded the time it took for the response by recording the startle was observed by body response or dialogue or both. number of 10ths of a second. The time counted was the time Cursing was not sufficient to be coded as startle, because between the alert and when the look was initiated, not includ- it may have resulted from anger or frustration, not startle. ing the moment of the alert or the moment of response. If the This category tried to capture startle to either the situation response was initiated within 1.0 s, the driver was considered or the alert. to have looked in response to the alert. The amount of time it took to look in response was always recorded for applicable 0 = No. situations, even if this was greater than 1.0 s. If the driver was 1 = Yes. already looking at the road and continued to look forward, the code was null (not applicable). If reviewers were not Steering in Response sure of the location of the driver's eyes, the time to visual response was left as null. The time to visual response was 0 = No steering in response to alert. (Small, jerky reactions recorded for Week 1, even though there was no alert to or slight wiggling in response to the alert or to the situation which to respond. The rationale for coding this was that a was classified as 0 and was not considered steering.) baseline would provide an idea of what a normal time to 1 = Driver steered partially or fully in response to the alert. visual response was compared with the time to response with (Steering, for review purposes, was an evasive maneuver in an alert. an attempt to avoid striking a vehicle; thus there must have been a significant amount of steering.) 0 = Looked in response. (The driver initiated a look in response to the alert within 1.0 s. Glances qualified as a look Hand Location at Time of Alert in response.) 1 = Did not look in response to alert. (The driver did not Both hands were not often visible, so reviewers coded what look within 1.0 s of the alert.) could confidently be inferred from the scene. At times, play- 2 = NA. (This option was always used for Week 1 because ing the video farther helped determine what was ambiguous there was no alert during Week 1; thus we could not code in a still frame at the time of the alert. For instance, at the time this category, although we still coded the time to visual of the alert there may have been a small blur near the steering response. This option was also selected when the driver was wheel. On continuation of the video the blur may have moved already looking forward at the time of the alert.) and come into view as a hand. 3 = Cannot tell. (The driver was wearing sunglasses or other glasses with glare, and reviewers could not tell where 0 = Cannot see the position of either hand or cannot the driver's eyes were.) determine the position of either hand. (Reviewers coded 0 if a hand could be seen but they could not tell if it was on the wheel.) Visual Occlusion 1 = At least one hand on steering wheel. (This was coded Occlusion was coded with regard to the driver as well as to when the position of one hand could not be determined reviewers. For instance, heavy rain or bright sun might have but reviewers could see that at least one hand was on the occluded the scene for both parties, whereas blurry video steering wheel.) occluded the scene only for the reviewer. The occlusion did 2 = Both hands on the steering wheel. not necessarily have to impact the reviewers' ability to code 3 = At least one hand off the steering wheel. (This was the scene. coded when the position of one hand could not be deter- mined but at least one hand was clearly off the steering 0 = None. wheel.) 1 = Sun or headlight glare. (This classification includes 4 = One hand on, one hand off the steering wheel. (The when the scene was whitewashed from the sun. Only head- classification was 4 when reviewers could clearly see both light glare was included in this section; taillight glare was hands and one was on the wheel but the other was off.) coded as other.) 5 = Both hands off the steering wheel. (This classification 2 = Other, specified in notes section. (The most common was used when reviewers could clearly see both hands and entry was taillight glare.) both were off the wheel.)

OCR for page 87
90 Secondary Driving Behaviors to the stereo but also adjusting the stereo. The car lighter was coded under the smoking section.) Audio was used to assist in coding whenever possible. For instance, reviewers may have heard the radio station change and seen the driver look at the console; this would indicate Smoking in-car system use. The default for nondriving behaviors was 70 = Lighting. (This classification includes the in-car lighter.) none, coded as 0. 71 = Reaching for cigarettes or lighter. (This classification includes the in-car lighter.) Cell Phone 72 = Smoking. 10 = Conversation, in use. (Conversation could be coded for listening, talking, or both while using the cell phone.) Grooming 11 = Reaching for phone. (This classification was used 80 = High involvement. (High involvement includes apply- when the driver reached for the handheld phone to speak ing makeup or brushing hair.) on that phone. If the driver reached for the phone simply 81 = Low involvement. (Low involvement includes scratch- to answer the phone and talk on the headset the driver ing or running one's fingers through his or her hair.) was wearing, the classification was other. Simply answer- 90 = Other/multiple behaviors, specified in notes section. ing the phone involves far less physical activity by the (Behaviors may include whistling or classifications that driver than reaching for the phone and holding it during reviewers were unsure of [e.g., if the driver's lips were mov- a conversation.) ing but there was no audio, the behavior might be singing 12 = Dialing phone. or conversation].) Headset, Hands-free Phone Seat Belt 20 = Conversation. (This was selected when reviewers could 0 = Yes. tell that the driver was in a conversation.) 1 = No. 21 = Reaching for headset. 2 = Cannot tell. 22 = Unsure of activity level. (The driver was wearing a headset but it was not clear whether the headset was in use. Curve Speed Warning System The driver may have been listening to someone or wearing Scenario Elements it in case of an incoming call.) Road Type 0 = Freeway/interstate. Eating 1 = Ramp. (A ramp was defined as an entrance or exit ramp 30 = High involvement. (High involvement includes such from a freeway or any ramp that connected two arterial activities as eating a burger or unwrapping food.) roads.) 31 = Low involvement. (Low involvement includes such 2 = Ramp near merge point. (Near was defined as being activities as eating candy or grabbing chips.) within 10 s of the merge point or within 10 s of arriving at the straightening of the ramp leading to a merge.) 3 = Surface road. Drinking 4 = Other. (Enter in notes.) 40 = High involvement. (High involvement includes situa- tions in which the driver was trying to open a straw or bottle Road Condition or was blowing on a hot drink.) 41 = Low involvement. (Low involvement includes situa- Glare and reflection helped determine whether the road was tions in which the driver was sipping a drink or drinking dry or wet. without looking.) 50 = Conversation. (The driver and someone in the car were 0 = Dry. carrying on a conversation. The driver can be listening 1 = Wet. (Any moisture on the road led to the classification during the clip, talking during the clip, or doing both.) as wet; there did not need to be standing water. The road 60 = In-car system use. (The driver was actively adjusting was classified as wet if it was wet from snow but not snow something. For example, the driver was not just listening covered.)

OCR for page 87
91 2 = Snow covered. (Snow covered included ice covered if it 0 = Confidence not high. was observed, but it was never observed. If any portion of 1 = Confidence high. the road, including turn lanes, was covered in snow, the classification was snow covered.) Nearby Overpass or Underpass The criteria were that the driver had to pass an overpass or Precipitation underpass 5 s before the alert or 10 s after the alert. Spots on the windshield or wiper activity helped determine if there was precipitation. 0 = No. 1 = Yes. 0 = None. 1 = Rain. (Light rain and drizzle were classified as rain, as Change in Number of Through Lanes were downpours.) 2 = Snow. (This category included sleet. Several cues helped 0 = No. indicate that the precipitation was snow. Snow tended to be 1 = Yes. larger and fall more slowly than rain, it looked like white flurries, and was present on the ground, reinforcing the Does the Vehicle Branch? classification as snow. Precipitation that occurred in December through February was assumed to be snow This addresses whether the vehicle is or will be taking a branch rather than rain. Snow could be coded in other months, but that triggers the CSWS alert. the assumption that the precipitation was snow was not as strong.) 0 = Not branching, and the alert is not triggered by a branch. (This can occur on a curvy rural road, for instance, or after the vehicle has exited onto a ramp and is approach- Number of Through Lanes ing a curve.) Turn lanes and dedicated exit lanes are not included in the 1 = Not branching, but passing branch that triggers alert. count of the number of through lanes. 2 = Branching onto segment that triggers alert. (This includes taking an exit or driving in a dedicated exit lane.) 1 = 1. 3 = Branching but alert was triggered by curve on initial 2 = 2. roadway. 3 = 3. 9 = No confidence in identifying the curve. 4 = 4 or more. Branch Type When Branch Is Triggering Alert Recent Lane Change If the roadway is a ramp, the ramp being traveled is not con- To be considered a recent lane change, the lane change had to sidered a branch. For instance, if the vehicle has exited the free- occur no more than 5 s before the alert or the car had to be in way onto an exit ramp and the roadway classification is ramp, the process of a lane change at the time of the alert. an alert triggered by a curve along that ramp would be coded as 0, no branch, because the vehicle is already on the ramp. 0 = No. 1 = Yes, toward branch that triggered the alert. 0 = A branch does not trigger the alert. 2 = Yes, away from the branch that triggered the alert. 1 = Ramp. 3 = Yes, but there was no branch triggering the alert or the 2 = Turn lane. branch triggering the alert is unknown. 3 = Michigan left. 4 = Intersection. 5 = Other. Curve Confidence 9 = No confidence in identifying the curve. This field was used to indicate when reviewers could not accu- rately determine which branch or curve triggered the alert. Road Geometry Most of the events categorized as confidence not high resulted from CSWS behavior that stems from artifacts of the map or 0 = Straight. CSWS implementation details. 1 = Curve.

OCR for page 87
92 2 = Approaching curve. (This classification constituted sit- the road, including turn lanes, was covered in snow, the uations in which the driver was approaching but not in a classification was snow covered.) curve at the time of the alert. The driver had to be driving through the curve within 5 s after the alert in order to be Precipitation classified as approaching curve.) Spots on the windshield or wiper activity helped determine if there was precipitation. Notes A notes section recorded any unusual events or ambiguous 0 = None. situations not covered by categories for a particular question. 1 = Rain. (Light rain and drizzle were classified as rain, as This section also contains general notes on the clip if there were downpours.) was anything significant taking place that was not adequately 2 = Snow. (This category included sleet. Several cues helped covered by the coding process. Examples of items captured in indicate that the precipitation was snow. Snow tended to be the notes section are described below, but other, unforeseen larger and fall more slowly than rain, it looked like white flur- events are also noted. ries and it was also present on the ground, reinforcing the classification as snow. Precipitation that occurred in Decem- Visual Occlusion ber through February was assumed to be snow rather than rain. Snow could be coded in other months, but the assump- Rear taillights, glare from rain and wetness on the road, blurry tion that the precipitation was snow was not as strong.) video, dirty windshield, temporary incapacitation, sneezing, flying debris, faulty wiper or defroster, and object in or over Road Curvature the driver's eyes. 0 = Straight. Nondriving Behaviors 1 = Right-hand curve. 2 = Left-hand curve. Whistling, two or more behaviors, if there is no audio and the driver is clearly talking or singing but reviewers could not tell which, attempting to avoid insect in car, adjusting mirrors, read- Lane Marking Change ing map, reading other materials, checking watch, or yawning. 0 = No. 1 = Yes. LDWS Scenario Elements Road Type Boundary Type 0 = Freeway/interstate. This field refers to which type of boundary was on the side of the 1 = Ramp. alert. For example, for an imminent LDW to the left in which 2 = Ramp near merge point. (Near is defined as being within there was a solid lane boundary to the left, it would be coded 10 s of the merge point or within 10 s of arriving at the as 0. Options 4 and 5 refer to double-boundary situations. straightening of the ramp leading to a merge.) 3 = Surface road. 0 = Solid. 4 = Other. (Enter in notes.) 1 = Dashed. 2 = Double solid. 3 = No marking. Road Condition 4 = Solid/dashed. Glare and reflection helped determine whether the road was 5 = Dashed/solid. dry or wet. 6 = Curb. 7 = Cannot tell. 0 = Dry. 1 = Wet. (Any moisture on the road led to the classification Continuous Incidental Feature as wet; there did not need to be standing water. The road was classified as wet if it was wet from snow but not snow This feature applies to continuous markings on the road that covered.) are not lane lines but may appear as lane lines to the LDWS-- 2 = Snow covered. (Snow covered included ice covered if it for example, tar markings, shadows, or tire marks on wet was observed, but it was never observed. If any portion of pavement.

OCR for page 87
93 0 = No. 0 = Median/open space. 1 = Yes. 1 = Solid barrier. 2 = Turning lane. 3 = Empty lane. Badly Placed Boundary 4 = Adjacent same-direction vehicle. At times the LDWS's real or virtual boundary was not prop- 5 = Fixed, discrete objects. erly placed according to actual conditions on the roadway. 6 = Construction zone. 7 = Stalled/slow traffic in adjacent lane. 0 = No. 8 = Curb. 1 = Yes. 9 = Other/unknown. 10 = Adjacent opposing-direction vehicle. Boundary Interaction Additional Driving Circumstances Ultimately, the position of the vehicle's tires was used to determine its position in the lane. At the time of the alert, if These circumstances are intentional maneuvers by the driver the tires were on or over the lane line, the crossed/straddled that help explain why the vehicle crossed the boundary or, in the line option was selected. case of corrected per the alert, the action the driver took after the alert. 0 = Crossed/straddled line at alert. 1 = Lane change at alert. 0 = None. 2 = Centered/slightly off-center in lane. 1 = Cut behind a car. 3 = Drifted in lane. 2 = Clear a temporary obstacle. 3 = Make room for a large truck. 4 = Corrected per the alert. Postboundary Maneuver 5 = Early or late exit/merge. This field evaluates the first maneuver the vehicle makes after the alert. For example, if the vehicle was drifting in the lane False Alert Comments at the time of the alert, then crossed the lane line, and finally returned to its original lane, only the eventually crossed option 0 = None. would be selected. The fact that the vehicle had ultimately 1 = Cannot identify target. (For a radar-induced alert.) returned to its original lane was addressed in the additional driv- 2 = Target seems far. (For a radar-induced alert, the target ing circumstances field, option corrected per the alert, which had to be within two-thirds of the lane width from the is detailed in the Additional Driving Circumstances section. vehicle to be considered valid.) 3 = Appears too sensitive. (This classification is usually 0 = Eventually crossed. applied when it appeared that the driver was not drifting.) 1 = Eventually returned to original lane. 4 = Other. (List in notes.) 2 = Stayed in lane. Lighting Issues Beyond the Boundary 0 = None. The area within two-thirds of a lane width and outside the 1 = Possible road reflection. boundary in question was considered in this evaluation. 2 = Recent change in road illumination. Although the choices were not mutually exclusive, no attempt was made to quantify everything beyond the boundary. Notes If the alert was propagated by the camera, the area directly to the right or left of the vehicle was evaluated. If, how- A notes section recorded any unusual events or ambiguous ever, information from the radar produced the alert, every situations not covered by categories for a particular question. effort was made to discern which object(s) had provoked This section also contains general notes on the clip if anything the alert based on available maneuvering room (AMR) bin significant was taking place that was not adequately covered information. by the coding process.