APPENDIX C: DATA REDUCTION VARIABLES

1. Vehicle Number

Comment: Each vehicle will be assigned a vehicle number. Information will originate in the raw data stream.

FORMAT: Integer value.

2. Epoch Number
The Epoch file number is arranged by vehicle identification number, date and time. The first three numbers represent the vehicle identification number, the next two numbers represent the year (Ex. 03 for 2003), the next two numbers represents the month (Ex. 03 for March), the next two numbers represent the day of the month, the next four numbers represent the time in military time. The last six numbers are the epoch ID.

002 03 02 28 1209 000000

Comment: Each valid driving performance trigger will be assigned to an epoch. An epoch will consist of 1 minute of video prior and 30 seconds of video after the initial onset of a trigger. If a second trigger occurs within this 1.5-minute segment, the epoch will extend to include a full one minute prior to the onset of the initial trigger and 30 seconds after the onset of the last trigger.

3. Event Severity – A general term referring to all valid triggered occurrences of an incident, near-crash, or crash that begins at the precipitating event and ends when the evasive maneuver has been completed.

Invalid trigger – Any instance where a trigger appears but no safety-relevant event is present.

Non-subject conflict - Any safety-relevant event captured on video (incident, near-crash, or crash) that does not involve the driver.

Non-conflict - Any event that increases the level of risk associated with driving, but does not result in a crash, near-crash, or incident, as defined below. Examples include: driver control error without proximal hazards being present; driver judgment error such as unsafe tailgating or excessive speed; or cases in which drivers are visually distracted to an unsafe level.

Proximity Event - Any circumstance resulting in extraordinarily close proximity of the subject vehicle to any other vehicle, pedestrian, cyclist, animal, or fixed object where, due to apparent unawareness on the part of the driver(s), pedestrians, cyclists or animals, there is no avoidance maneuver or response. Extraordinarily close proximity is defined as a clear case where the absence of an avoidance maneuver or response is inappropriate for the driving circumstances (including speed, sight distance, etc.).

Crash-Relevant - Any circumstance that requires a crash avoidance response on the part of the subject vehicle. Any other vehicle, pedestrian, cyclist, or animal that is less severe than a rapid evasive maneuver (as defined above), but greater in severity than a “normal maneuver” to avoid a crash. A crash avoidance response can include braking, steering, accelerating, or any combination of control inputs. A “normal maneuver” for the subject vehicle is defined as a control input that falls inside of the 99 percent confidence limit for control input as measured for the same subject.

Near-crash - Any circumstance that requires a rapid, evasive maneuver by the subject vehicle, or any other vehicle, pedestrian, cyclist, or animal to avoid a crash. A rapid, evasive maneuver is defined as a steering, braking, accelerating, or any combination of control inputs that approaches the limits of the vehicle capabilities. As a guide: subject vehicle braking greater than 0.5 g, or steering input that results in a lateral acceleration greater than 0.4 g to avoid a crash, constitutes a rapid maneuver.

Crash - Any contact with an object, either moving or fixed, at any speed, in which kinetic energy is measurably transferred or dissipated. Includes other vehicles, roadside barriers, objects on or off the roadway, pedestrians, cyclists or animals.

Comment: Initial coding step. Invalid events result in no further coding. Non-subject and non-conflicts will only result in a brief narrative written, but no other coding. Other coding choices will determine which specific subset of variables that will be coded. Specified at early onset of data reduction software.

4. Trigger Type (C-N-I)
The triggers were specific data signatures that were specified during the sensitivity analysis performed after 10 percent of the data were collected. The specific data signatures that were used to identify valid events are as follows:

Lateral acceleration - Lateral motion equal or greater than 0.7 g.
Longitudinal acceleration - Acceleration or deceleration equal or greater than 0.6 g.
CI button – Activated by the driver upon pressing a button located on the dashboard when an incident occurred that he/she deemed critical.

Forward Time To Collision (FTTC) - Acceleration or deceleration equal to or greater than 0.5 g coupled with a forward TTC of 4 seconds or less.
All longitudinal decelerations between 0.4 g and 0.5 g coupled with a forward TTC value of ≤ 4 seconds and that the corresponding forward range value at the minimum TTC is not greater than 100 feet.
Rear Time To Collision (RTTC) - Any rear TTC trigger value of 2 seconds or less that also has a corresponding rear range distance of ≤ 50 feet AND any rear TTC trigger value where the absolute acceleration of the following vehicle is greater than 0.3 g.
Side object detection – Detects presence of other vehicles/objects in the adjacent lane.
Lane change cut-off – Identifies situations in which the subject vehicle cuts in too close either behind or in front of another vehicle by using closing speed and forward TTC.
Yaw rate – Any value greater than or equal to a plus AND minus 4-degree change in heading (i.e., vehicle must return to the same general direction of travel) within a 3-second window of time.

5. Driver Subject Number (C-N-I-B)
All primary drivers’ subject number will be a 3-digit number followed by the letter “A.” Any secondary drivers should be given the same 3-digit number followed by the letters “B,” “C,” and so on.

6. Onset of Precipitating Factor
Using video frame numbers, the reductionists will determine the onset of the precipitating event (i.e., onset of lead-vehicle brake lights for a lead vehicle conflict).

7. Resolution of the Event
Using video frame numbers, the reductionists will determine when the evasive maneuver (or lack thereof) has been executed and the level of danger has returned to normal.

EVENT VARIABLES

1. Event Nature (C-N-I)

This variable specified the type of crash, near-crash, or incident that occurred. The reductionists chose from the following variables that were modified from GES variables “Manner of Collision” and “Most Harmful Event.”

1=Conflict with a lead vehicle
2=Conflict with a following vehicle
3=Conflict with an oncoming traffic
4=Conflict with a vehicle in adjacent lane
5=Conflict with a merging vehicle
6=Conflict with a vehicle turning across subject vehicle path (same direction)
7=Conflict with a vehicle turning across subject vehicle path (opposite direction)
8=Conflict with a vehicle turning into subject vehicle path (same direction)
9=Conflict with a vehicle turning into subject vehicle path (opposite direction)
10 =Conflict with a vehicle moving across subject vehicle path (through intersection)
11=Conflict with a parked vehicle
12=Conflict with a pedestrian
13=Conflict with a pedal cyclist
14=Conflict with an animal
15=Conflict with an obstacle/object in roadway
16=Single vehicle conflict
17=Other
18=No known conflict (for RF sensor trigger)
99=Unknown conflict

2. Incident Type (Coded for Crashes and Near-Crashes only)

1 = Rear-end, striking
2 = Rear-end, struck
3 = Road departure (left or right)
4 = Road departure (end)
5 = Sideswipe, same direction (left or right)
6 = Opposite direction (head-on or sideswipe)
7 = Violation of stop sign or signal at intersection
8 = Straight crossing path, not involving sign/signal violation
9 = Turn across path
10 = Turn into path (same direction)
11 = Turn into path (opposite direction)
12 = Backing, fixed object
13 = Backing into traffic
14 = Pedestrian
15 = Pedalcyclist
16 = Animal
17 = Other (specify)
99 = Unknown

3. Pre-Event Maneuver (GES Variable Vehicle 1 Maneuver Prior to Event)
This represents the last action that the subject vehicle driver engaged in just prior to
the point that the driver realized impending danger. Note that the variables in italics
are those GES variables that were expanded.

1a = Going straight, constant speed
1b = Going straight ahead, accelerating
1c = Going straight, but with unintentional “drifting” within lane or across lanes
2 = Decelerating in traffic lane
3 = Accelerating in traffic lane
4 = Starting in traffic lane
5 = Stopped in traffic lane
6 = Passing or overtaking another vehicle
7 = Disabled or parked in travel lane
8 = Leaving a parked position
9 = Entering a parked position
10 = Turning right
11 = Turning left
12 = Making U-turn
13 = Backing up (other than for parking purposes)
14 = Negotiating a curve
15 = Changing lanes
16 = Merging
17 = Successful corrective action to previous action
18a = Maneuvering to avoid an animal
18b = Maneuvering to avoid a pedestrian/pedalcyclist
18c = Maneuvering to avoid an object
18d = Maneuvering to avoid a vehicle
97 = Other
99 = Unknown

Source/comment: GES Variable V21, Movement Prior to Critical Event. Also, very similar to VA PAR%Variable 19/20.
FORMAT: Integer value as listed above.

4. Judgment of Vehicle 1 Maneuver Prior to Event
This variable provided additional information about the pre-event maneuver as to whether this maneuver was either safe or legal.

1 = Safe and legal
2 = Unsafe but legal
3 = Safe but illegal
4 = Unsafe and illegal
99 = Unknown

5. Precipitating Factor (GES Variable V26, Critical Event)
The driver behavior or state of the environment that begins the event and the
subsequent sequence of actions that result in a crash, near-crash, or incident,
independent of who caused the event (driver at fault). The precipitating factor occurs
outside the vehicle and does not include driver distraction, drowsiness, or disciplining
child while driving.

A. This Vehicle Loss of Control Due to:

001 = Blow-out or flat tire
002 = Stalled engine
003 = Disabling vehicle failure (e.g., wheel fell off)
004 = Minor vehicle failure
005 = Poor road conditions (puddle, pothole, ice, etc.)
006 = Excessive speed
007 = Other or unknown reason
008 = Other cause of control loss
009 = Unknown cause of control loss

B. This Vehicle Traveling:

018a = Ahead, stopped on roadway more than 2 seconds
018b = Ahead, decelerated and stopped on roadway 2 seconds or less
021 = Ahead, traveling in same direction and decelerating
022 = Ahead, traveling in same direction with slower constant speed
010 = Over the lane line on the left side of travel lane
011 = Over the lane line on right side of travel lane
012 = Over left edge of roadway
013 = Over right edge of roadway
014 = End departure
015 = Turning left at intersection
016 = Turning right at intersection
017 = Crossing over (passing through) intersection
019 = Unknown travel direction
020a = From adjacent lane (same direction), over left lane line behind lead vehicle, rear-end crash threat
020b = From adjacent lane (same direction), over right lane line behind lead vehicle, rear-end crash threat

C. Other Vehicle in Lane:

050a = Ahead, stopped on roadway more than 2 seconds
050b = Ahead, decelerated and stopped on roadway 2 seconds or less
051 = Ahead, traveling in same direction with slower constant speed
052 = Ahead, traveling in same direction and decelerating
053 = Ahead, traveling in same direction and accelerating
054 = Traveling in opposite direction
055 = In crossover
056 = Backing
059 = Unknown travel direction of the other motor vehicle

Another Vehicle Encroaching into This Vehicle’s Lane:

060a = From adjacent lane (same direction), over left lane line in front of this vehicle, rear-end crash threat
060b = From adjacent lane (same direction), over left lane line behind this vehicle, rear-end crash threat
060c = From adjacent lane (same direction), over left lane line, sideswipe threat
060d = From adjacent lane (same direction), over right lane line, sideswipe threat
060e = From adjacent lane (same direction), other
061a = From adjacent lane (same direction), over right lane line in front of this vehicle, rear-end crash threat
061b = From adjacent lane (same direction), over right lane line behind this vehicle, rear-end crash threat
061c = From adjacent lane (same direction), other
062 = From opposite direction over left lane line.
063 = From opposite direction over right lane line
064 = From parallel/diagonal parking lane
065 = Entering intersection—turning in same direction
066 = Entering intersection—straight across path
067 = Entering intersection – turning into opposite direction
068 = Entering intersection—intended path unknown
070 = From driveway, alley access, etc. – turning into same direction
071 = From driveway, alley access, etc. – straight across path
072 = From driveway, alley access, etc. – turning into opposite direction
073 = From driveway, alley access, etc. – intended path unknown
074 = From entrance to limited access highway
078 = Encroaching details unknown

E. Pedestrian, Pedalcyclist, or other Non-Motorist:

080 = Pedestrian in roadway
081 = Pedestrian approaching roadway
082 = Pedestrian in unknown location
083 = Pedalcyclist/other nonmotorist in roadway
084 = Pedalcyclist/other nonmotorist approaching roadway
085 = Pedalcyclist/or other nonmotorist unknown location
086 = Pedestrian/pedalcyclist/other nonmotorist—unknown location

F. Object or Animal:

087 = Animal in roadway
088 = Animal approaching roadway
089 = Animal unknown location
090 = Object in roadway
091 = Object approaching roadway
092 = Object unknown location
099 = Unknown critical event

6. Evasive Maneuver (GES Variable V27 Corrective Action Attempted)
The subject vehicle driver’s reaction to the precipitating factor.

0 = No driver present
1 = No avoidance maneuver
2 = Braking (no lockup)
3 = Braking (lockup)
4 = Braking (lockup unknown)
5 = Releasing brakes
6 = Steered to left
7 = Steered to right
8 = Braked and steered to left
9 = Braked and steered to right
10 = Accelerated
11 = Accelerated and steered to left
12 = Accelerated and steered to right
98 = Other actions
99 = Unknown if driver attempted any corrective action

7. Vehicle Control After Corrective Action (GES Variable V28—Coded only
for near-crashes and crashes):

0 = No driver present
1 = Vehicle control maintained after corrective action
2 = Vehicle rotated (yawed) clockwise
3 = Vehicle rotated (yawed) counter-clockwise
4 = Vehicle slid/skid longitudinally – no rotation
5 = Vehicle slid/skid laterally – no rotation
9 = Vehicle rotated (yawed) unknown direction
20 = Combination of 2-9
94 = More than two vehicles involved
98 = Other or unknown type of vehicle control was lost after corrective action
99 = Unknown if vehicle control was lost after corrective action.

Contributing Factors

1. Driver Behavior: Driver 1 Actions/Factors Relating to the Event (VA PAR%Variable 17/18)
This variable provides a descriptive label to the driver’s actions that may or may not have contributed to the event.

0 = None
1 = Exceeded speed limit
2 = Inattentive or distracted
3 = Exceeded safe speed but not speed limit
4 = Driving slowly: below speed limit
5 = Driving slowly in relation to other traffic: not below speed limit
6 = Illegal passing (i.e., across double line)
7 = Passing on right
8 = Other improper or unsafe passing
9 = Cutting in, too close in front of other vehicle
10 = Cutting in, too close behind other vehicle
11 = Making turn from wrong lane (e.g., across lanes)
12 = Did not see other vehicle during lane change or merge
13 = Driving in other vehicle’s blind zone
14 = Aggressive driving, specific, directed menacing actions
15 = Aggressive driving, other, i.e., reckless driving without directed menacing
actions
16 = Wrong side of road, not overtaking
17 = Following too close
18 = Failed to signal, or improper signal
19 = Improper turn - wide right turn
20 = Improper turn - cut corner on left turn
21 = Other improper turning
22 = Improper backing, did not see
23 = Improper backing, other
24 = Improper start from parked position
25 = Disregarded officer or watchman
26 = Signal violation, apparently did not see signal
27 = Signal violation, intentionally ran red light
28 = Signal violation, tried to beat signal change
29 = Stop sign violation, apparently did not see stop sign
30 = Stop sign violation, intentionally ran stop sign at speed
31 = Stop sign violation, “rolling stop”
32 = Other sign (e.g., Yield) violation, apparently did not see sign
33 = Other sign (e.g., Yield) violation, intentionally disregarded
34 = Other sign violation
35 = Non-signed crossing violation (e.g., driveway entering roadway)
36 = Right-of-way error in relation to other vehicle or person, apparent recognition failure (e.g., did not see other vehicle)
37 = Right-of-way error in relation to other vehicle or person, apparent decision
failure (i.e., did see other vehicle prior to action but misjudged gap)
38 = Right-of-way error in relation to other vehicle or person, other or unknown cause
39 = Sudden or improper stopping on roadway
40 = Parking in improper or dangerous location, e.g., shoulder of Interstate
41 = Failure to signal with other violations or unsafe actions
42 = Failure to signal, without other violations or unsafe actions
43 = Speeding or other unsafe actions in work zone
44 = Failure to dim headlights
45 = Driving without lights or insufficient lights
46 = Avoiding pedestrian
47 = Avoiding other vehicle
48 = Avoiding animal
49 = Apparent unfamiliarity with roadway
50 = Apparent unfamiliarity with vehicle, e.g., displays and controls
51 = Apparent general inexperience driving
52 = Use of cruise control contributed to late braking
53 = Other, specify

2. Driver 1 Physical/Mental Impairment (GES Variable D3: Driver Physical/Mental Condition)

0 = None apparent
1 = Drowsy, sleepy, asleep
2 = Ill, blackout
3a = Angry
3b = Other emotional state
4a = Drugs-medication
4b = Drugs-Alcohol
5 = Other drugs (marijuana, cocaine, etc.)
6 = Restricted to wheelchair
7 = Impaired due to previous injury
8 = Deaf
50 = Hit and run vehicle
97 = Physical/mental impairment – no details
98 = Other physical/mental impairment
99 = Unknown physical/mental condition

Source: GES D3, Driver Physical/Mental Condition. Element 3 expanded to
separate anger from other emotions. Element 50 not applicable.
Coded in General State Variables: Driver’s General State, Causal/Contributing
Factors, and Precipitating Event.
FORMAT: 16-bit encoded value(s) as listed above.

3. Driver 1 Distracted By (GES Variable D7: Driver Distracted By)
This variable was recorded if the reductionists observed the drivers engaging in
any of the following secondary tasks 5-10 seconds prior to the onset of the
precipitating factor. For a complete definition of these tasks, see Appendix D.

00 = Not Distracted

15 = Cognitive distraction
97 = Lost in thought
01 = Looked but did not see
15a = Reading
15b = Talking/singing without obvious passenger
15c = Dancing to the radio
15d = Reading

03 = Passenger in vehicle
3a = Passenger in adjacent seat
3b = Passenger in rear seat
3c = Child in adjacent seat
3d = Child in rear seat

= Object/Animal/Insect in Vehicle
4a = Moving object in vehicle (i.e., object fell off seat when driver stopped
hard at a traffic light)
4b = Insect in vehicle
4c = Pet in vehicle
4d = Object dropped by driver
4e = Reaching for object in vehicle (not cell phone)

5 = Cell phone operations
05a = Talking/listening
06a = Dialing hand-held cell phone
06b = Dialing hand-held cell phone using quick keys
06c = Dialing hands-free cell phone using voice activated software
06d = Locating/reaching/answering cell phone

17 = PDA operations
15a = Locating/reaching PDA
15b = Operating PDA
15c = Viewing PDA

16 = In-vehicle system operations
7 = Adjusting climate control
8a = Adjusting the radio
8b = Inserting/retrieving cassette
8c = Inserting/retrieving CD
9 = Adjusting other devices integral to vehicle (unknown which device)
9a = Adjusting other known in-vehicle devices (text box to specify)

12 = External Distraction
12a = Looking at previous crash or highway incident
12b = Pedestrian located outside the vehicle
12c = Animal located outside the vehicle
12d = Object located outside the vehicle
12e = Construction zone

= Dining
13a = Eating with a utensil
13b = Eating without a utensil
13c = Drinking from a covered container (i.e., straw)
13d = Drinking from an uncovered container

= Smoking
14a = Reaching for cigar/cigarette
14b = Lighting cigar/cigarette
14c = Smoking cigar/cigarette
14d = Extinguishing cigar/cigarette

18. Personal Hygiene
18a = Combing/brushing/fixing hair
18b = Applying make-up
18c = Shaving
18d = Brushing/flossing teeth
18e = Biting nails/cuticles
18f = Removing/adjusting jewelry
18g = Removing/inserting contact lenses
18h = Other

19. Inattention to the Forward Roadway
19a = Left window
19b = Left rear-view mirror
19c = Center rear-view mirror
19d = Right rear-view mirror
19e = Right passenger window

3a. Time Distraction Began
Reductionists entered the video frame number corresponding to the time at which the driver became distracted or began to engage in the distracting task.

3b. Time Distraction Ended
Reductionists entered the video frame number corresponding to the time at which the driver disengaged from the distracting task or the driver’s attention returned to the forward roadway.

3c. Outcome (of Incident) Impacted
Reductionists also marked whether they believed that the secondary task that was present at the onset of the precipitating factor impacted the severity or the outcome of the event. Note that all distraction analyses conducted in this report only used those secondary tasks that were marked ‘yes’ or ‘not able to determine’.

1 = Yes
2 = No
3 = Not able to determine
99 = Unknown

4. Willful Behavior
Reductionists marked this variable when they believed that the driver was aware or cognizant of their poor behavior. There were 3 options, written in sequential order of increasingly willful or aggressive behavior.

1 = Aggressive driving
2 = Purposeful violation of traffic laws
3 = Use of vehicle for improper purposes (Intimidation/weapon)
99 = Unknown

Source/comment: This variable came from the Light/Heavy Vehicle Interaction Study Taxonomy.

5. Driver Proficiency
Reductionists marked this variable when it was believed that the driver was generally unaware of their poor driving behavior. There are 4 options, written in order of decreasing levels of proficiency (the last is the most drastic measure of poor driving proficiency).

1 = Violation of traffic laws
2 = Driving techniques (incompetent to safely perform driving maneuver)
3 = Vehicle kinematics (incompetent handling the vehicle)
4 = Driver capabilities (incompetent on what maneuvers are safe and
appropriate)

Source/comment: This variable came from the Light/Heavy Vehicle Interaction Study Taxonomy.

6. Driver 1 Drowsiness Rating (Coded for Crashes and Near-Crashes only)
An observer rating of drowsiness will be assigned for the 30 seconds prior to the event based on review of driver videos. For drowsiness levels above a criterion level of and ORD of 60 or above, a manual calculation of PERCLOS will be measured by the analyst. This variable will be coded for all crashes and near-crashes (Wierwille and Ellsworth, 1994).

7. Driver 1 Vision Obscured by (GES Variable D4: Vision Obscured by)
Reductionists will ascertain to the best of their ability whether the driver’s vision was obscured by any of the following:

0 = No obstruction
1 = Rain, snow, fog, smoke, sand, dust
2a = Reflected glare
2b = Sunlight
2c = Headlights
3 = Curve or hill
4 = Building, billboard, or other design features (includes signs,
embankment)
5 = Trees, crops, vegetation
6 = Moving vehicle (including load)
7 = Parked vehicle
8 = Splash or spray of passing vehicle [any other vehicle]
9 = Inadequate defrost or defog system
10 = Inadequate lighting system
11 = Obstruction interior to vehicle
12 = Mirrors
13 = Head restraints
14 = Broken or improperly cleaned windshield
15 = Fog
50 = Hit-and-run vehicle
95 = No driver present
96 = Not reported
97 = Vision obscured – no details
98 = Other obstruction
99 = Unknown whether vision was obstructed

8. Vehicle Contributing Factors (GES Variable V12, Vehicle contributing factors)
Reductionists will determine if any of the following contributed to the severity or the presence of an event.

0 = None
1 = Tires
2 = Brake system
3 = Steering system
4 = Suspension
5 = Power train
6 = Exhaust system
7 = Headlights
8 = Signal lights
9 = Other lights
10 = Wipers
11 = Wheels
12 = Mirrors
13 = Driver seating and controls
14 = Body, doors
15 = Trailer hitch
50 = Hit and run vehicle
97 = Vehicle contributing factors, no details
98 = Other vehicle contributing factors
99 = Unknown if vehicle had contributing factors

Environmental Factors: Driving Environment

1. Weather (GES Variable A20I, Atmospheric condition and VA PAR%Variable 4)
Reductionists will determine the type of weather using the video and record as part of the data reduction process.

1 = Clear
2 = Cloudy
3 = Fog
4 = Mist
5 = Raining
6 = Snowing
7 = Sleeting
8 = Smoke dust
9 = Other
99 = Unknown

2. Light (GES Variable A19I, Light Condition and VA PAR% Variable 7)
Reductionists will determine the type of ambient light conditions are present using the video and record as part of the data reduction process.

1 = Dawn
2 = Daylight
3 = Dusk
4 = Darkness, lighted
5 = Darkness, not lighted
99 = Unknown

3. Windshield Wiper Activation
Analysts will determine the windshield wiper activation through video reduction.

0 = Off
1 - On
99 = Unknown

4. Surface Condition (VA PAR%Variable 5)
Reductionists will determine the type of surface condition at the onset of the
precipitating factor and record as part of the data reduction process.

1 = Dry
2 = Wet
3 = Snowy
4 = Icy
5 = Muddy
6 = Oily
7 = Other
99 = Unknown

5. Traffic Density (Level of Service)
Reductionists will determine the level of traffic density at the time of the precipitating factor and record as part of the data reduction process.

1 = LOS A: free flow
2 = LOS B: Flow with some restrictions
3 = LOS C: Stable flow, maneuverability and speed are more restricted
4 = LOS D: Unstable flow – temporary restrictions substantially slow
driver
5 = LOS E: Flow is unstable, vehicles are unable to pass, temporary
stoppages, etc.
6 = LOS F: Forced traffic flow condition with low speeds and traffic
volumes that are below capacity. Queues forming in particular
locations.
99 = Unknown

Driving Environment: Infrastructure
1. Kind of Locality (VA PAR%Variable 8)
Reductionists will determine the kind of locality at the onset of the precipitating factor and record as part of the data reduction process.

1 = School
2 = Church
3 = Playground
4 = Open Country
5 = Business/industrial
6 = Residential
7 = Interstate
8 = Other
9= Construction Zone (Added)
99 = Unknown

2. Relation to Junction (GES Variable A9)
Reductionists will determine the whether the precipitating factor occurred near a roadway junction and record as part of the data reduction process.

Non-Interchange Area
00 = Non-Junction
01 = Intersection
02 = Intersection-related
03 = Driveway, alley access, etc.
04 = Entrance/exit ramp
05 = Rail grade crossing
06 = On a bridge
07 = Crossover related
08 = Other, non-interchange area
09 = Unknown, non-interchange
20 = Parking lot [Added]

FORMAT: Integer value as listed above.

Interchange Area
10 = Non-Junction
11 = Intersection
12 = Intersection-related
13 = Driveway, alley access, etc.
14 = Entrance/exit ramp
16 = On a bridge
17 = Crossover related
18 = Other location in interchange area
19 = Unknown, interchange area
99 = Unknown if interchange

3. Trafficway Flow (GES Variable A11)
Reductionists will determine the whether the roadway was divided at the time of the precipitating factor and record as part of the data reduction process.

1 = Not divided
2 = Divided (median strip or barrier)
3 = One-way traffic
99 = Unknown

4. Number of Travel Lanes (GES Variable A12)
Reductionists will determine the number of travel lanes at the time of the precipitating factor and record as part of the data reduction process.

1 = 1
2 = 2
3a = 3 lanes in direction of travel (divided or one-way trafficway)
3b = Undivided highway, 3 lanes total, 2 in direction of travel
3c = Undivided highway, 3 lanes total, 1 in direction of travel
4 = 4
5 = 5
6 = 6
7 = 7+
99 = Unknown

5. Traffic Control (VA PAR%Variable 1)
Reductionists will determine whether there was a traffic control device present and record as part of the data reduction process.

1 = No traffic control
2 = Officer or watchman
3 = Traffic signal
4 = Stop sign
5 = Slow or warning sign
6 = Traffic lanes marked
7 = No passing signs
8 = Yield sign
9 = One way road or street
10 = Railroad crossing with markings or signs
11 = Railroad crossing with signals
12 = Railroad crossing with gate and signals
13 = Other
99 = Unknown

Source: VA PAR%Variable 1.
Coded in General State Variables: Road/Traffic Variables.
FORMAT: Integer value as listed above.

6. Alignment (VA PAR%Variable 3)
Reductionists will determine whether there what the road alignment was at the onset of the precipitating factor and record as part of the data reduction process.

1 = Straight level
2 = Curve level
3 = Grade straight
4 = Grade curve
5 = Hillcrest straight
6 = Hillcrest curve
7 = Dip straight
8 = Up curve
9 = Other
99 = Unknown

DRIVER STATE VARIABLES

1. Driver 1 Hands on Wheel (C-N-I-B)
Reductionists will the number of hands the driver had on the steering wheel at the time of the precipitating factor and record as part of the data reduction process.

0 = None
1 = Left hand only
2 = Both hands
3 = Right hand only
99 = Unknown

2. Occupant Safety Belt Usage (C)
Reductionists will determine whether the driver had a seatbelt fastened at the time of the precipitating factor and record as part of the data reduction process.

1 = Lap/shoulder belt
2 = Lap belt only
3 = Shoulder belt only
5 = None used
99 = Unknown if used.

3. Driver 1 Alcohol Use (GES Variable V92)
Reductionists will determine whether drivers were using alcohol or under the influence of alcohol at the time of the precipitating factor and record as part of the data reduction process.

1a = Use observed in vehicle without overt effects on driving
1b = Use observed in vehicle with overt effects on driving
1c = Use not observed but reported by police
1d = Use not observed or reported, but suspected based on driver behavior.
2 = None known
99 = Unknown

4. Fault Assignment
1 = Driver 1 (subject vehicle)
2 = Driver 2
3 = Driver 3
4 = Driver 4
5 = Driver 5
6 = Driver 6
7 = Driver 7
8 = Driver 8
9 = Driver 9
10 = Driver 10
11 = Other (textbox)
99 = Unknown

5. Observer Rating of Drowsiness (ORD)

For crashes and near-crashes, reductionists rated the driver’s drowsiness on a scale of 0-100. The procedure for measuring ORD was developed and first used by Wierwille and Ellsworth (1994). This scale is broken down as is shown in Figure C-1.

Figure C-1. The observer rating of drowsiness scale where not drowsy is equal to 0 and extremely drowsy is equal to 100.

Reductionists were instructed to watch the driver’s face and body language for a period of time prior to the trigger. As described by Wierwille and Ellsworth (1994), signs indicative of drowsiness include rubbing face or eyes, facial contortions, moving restlessly in the seat, and slow eyelid closures. Reductionists were trained to look for these signs of drowsiness and make a subjective but specific assessment of the level of drowsiness. After watching the video data, reductionists employed a rating scale to record an ORD level. Please note that for a driver to be considered ‘”drowsy” in all of the analyses in this report, the ORD rating needed to be 60 or higher. The specific drowsy behaviors that reductionists used to rate a driver’s drowsiness level were as follows:

• Not Drowsy: A driver who is not drowsy while driving will exhibit behaviors such that the appearance of alertness will be present. For example, normal facial tone, normal fast eye blinks, and short ordinary glances may be observed. Occasional body movements and gestures may occur.
  
  
• Slightly Drowsy: A driver who is slightly drowsy while driving may not look as sharp or alert as a driver who is not drowsy. Glances may be a little longer and eye blinks may not be as fast. Nevertheless, the driver is still sufficiently alert to be able to drive.
  
  
• Moderately Drowsy: As a driver becomes moderately drowsy, various behaviors may be exhibited. These behaviors, called mannerisms, may include rubbing the face or eyes, scratching, facial contortions, and moving restlessly in the seat, among others. These actions can be thought of as countermeasures to drowsiness. They occur during the intermediate stages of drowsiness. Not all individuals exhibit mannerisms during intermediate stages. Some individuals appear more subdued, they may have slower closures, their facial tone may decrease, they may have a glassy-eyed appearance, and they may stare at a fixed position.
  
  
• Very Drowsy: As a driver becomes very drowsy eyelid closures of 2 to 3 seconds or longer usually occur. This is often accompanied by a rolling upward or sideways movement of the eyes themselves. The individual may also appear not to be focusing the eyes properly, or may exhibit a cross-eyed (lack of proper vergence) look. Facial tone will probably have decreased. Very drowsy drivers may also exhibit a lack of apparent activity and there may be large isolated (or punctuating) movements, such as providing a large correction to steering or reorienting the head from a leaning or tilted position.
  
  
• Extremely Drowsy: Drivers who are extremely drowsy are falling asleep and usually exhibit prolonged eyelid closures (4 seconds or more) and similar prolonged periods of lack of activity. There may be large punctuated movements as they transition in and out of intervals of dozing.

6. Average PERCLOS (Percentage Eyes Closed) (C, N)
For crashes and near-crashes where the driver’s observer rating of drowsiness is above a criterion level an ORD of 60, the average PERCLOS value for the 30 seconds pre-event period will be obtained through video reduction.

7. Driver 1 Eyeglance Reconstruction (C-N)
Eyeglances for the previous 30 seconds will be classified using the following categories and described as a timed, narrative sequence of the following numbers:
1 = Center forward
2 = Left forward
3 = Right forward
4 = Left mirror
5 = Right mirror
6 = Left window
7 = Right window
8 = Instrument panel
9 = Passenger
10 = Object
11 = Cell Phone
12 = Other

Comment: The analysis will include a recording of time the driver’s eyes were not “on the road,” i.e., straight ahead, forward right, or forward left. When possible, eyeglances will be characterized in greater detail than the general directions and areas listed above, e.g., when known, the specific object of regard will be noted in the narrative. For the instrument panel, for example, specific components such as the radio/CD will be noted in the narrative. When applicable and possible, the eyeglance reconstruction will also include an assessment of driver reaction time to a stimulus, e.g., braking reaction time following a potential crash-precipitating event.

Driver/Vehicle 2

1. Number of other Vehicle/Person (s)
Reductionists will identify the number of vehicles in the immediate environment and then record the following variables.

2. Location of other Vehicle/Persons
Reductionists will identify the location of vehicles in the immediate environment with respect to the subject vehicle and then record the following variables.

A = In front of subject vehicle
B = In front and to the immediate right of the subject vehicle
C = On the right side of the subject vehicle, closer to front seat of the vehicle.
D = On the right side of the subject vehicle, closer to rear seat of the vehicle.
E = Behind and to the immediate right of the subject vehicle.
F = Behind the subject vehicle
G = Behind and to the immediate left of the subject vehicle.
H = On the left side of the subject vehicle, closer to the rear seat of the vehicle.
I = On the left side of the subject vehicle, closer to the front seat of the vehicle.
J = In front and to the immediate left of the subject vehicle.

3. Vehicle/Person 2 Type (Modified version of GES Variable V5, Body Type)
Data reductionists will record what type of vehicles that are in the subject vehicle’s immediate surroundings.

1 = Automobile
14 = Sport Utility Vehicles
20 = Van-based truck (minivan or standard van)
30 = Pickup truck
50 = School bus
58a = Transit bus
58b = Greyhound bus
58c = Conversion bus
64a = Single-unit straight truck: Multistop/step van
64b = Single-unit straight truck: Box
64c = Single-unit straight truck: Dump
64d = Single-unit straight truck: Garbage/recycling
64e = Single-unit straight truck: Concrete mixer
64f = Single-unit straight truck: Beverage
64g =Single-unit straight truck: Flatbed
64h =Single-unit straight truck: Tow truck
64i = Single-unit straight truck: Other
64j = Single-unit straight truck: Unknown
64k = Straight Truck + Trailer
66 = Tractor only
66a = Tractor-trailer: Enclosed box
66b = Tractor-trailer: Flatbed
66c = Tractor-trailer: Tank
66d = Tractor-trailer: Car carrier
66e = Tractor-trailer: Livestock
66f = Tractor-trailer: Lowboy trailer
66g = Tractor-trailer: Dump trailer
66h = Tractor-trailer: Multiple trailers/enclosed box
66i = Tractor-trailer: Multiple trailers/grain
66e = Tractor-trailer: Other
93 = Other Large Construction Equipment
8 = Motorcycle or moped
9a = Ambulance
9b = Fire truck
9c = Police
10 = Other vehicle type
11 = Pedestrian
12 = Cyclist
13 = Animal
99 = Unknown vehicle type
4. Vehicle 2 Maneuver (GES Variable V21, Movement Prior to Critical Event)
Reductionists will record what the other vehicle’s actions were just prior to the onset of the precipitating factor.

1 = Going straight ahead
2 = Making right turn
3 = Making left turn
4 = Making U-turn
5 = Slowing or stopping
6 = Starting in traffic lane
7 = Starting from parked position
8 = Stopped in traffic lane]
9 = Ran off road right
10 = Ran off road left
11 = Parked
12 = Backing
13 = Passing
14 = Changing lanes
15 = Other
16 = Accelerating in traffic lane
17 = Entering a parked position
18 = Negotiating a curve
19 = Merging
99 = Unknown

5. Driver/Vehicle 2 Corrective Action Attempted (GES V27, Corrective Action Attempted)
Reductionists will record the corrective action attempted for each vehicle immediately surrounding the subject vehicle.

0 = No driver present
1 = No avoidance maneuver
2 = Braking (no lockup)
3 = Braking (lockup)
4 = Braking (lockup unknown)
5 = Releasing brakes
6 = Steered to left
7 = Steered to right
8 = Braked and steered to left
9 = Braked and steered to right
10 = Accelerated
11 = Accelerated and steered to left
12 = Accelerated and steered to right
98 = Other actions
99 = Unknown if driver attempted any corrective action

Coded: From PAR%and/or video.
Source: GES V27, Corrective Action Attempted.
Coded in General State Variables: Driver/Vehicle 2.
FORMAT: Integer value as listed above.

6. Driver/Vehicle 2 Physical/Mental Impairment (GES D3, Driver Physical/Mental Condition)
Reductionists will mark only for those crashes that a police accident report form is collected from the subject.

0 = None apparent
1 = Drowsy, sleepy, asleep
2 = Ill, blackout
3a = Angry
3b = Other emotional state
4 = Drugs and medication
5 = Other drugs (marijuana, cocaine, etc.)
6 = Restricted to wheelchair
7 = Impaired due to previous injury
8 = Deaf
50 = Hit-and-run vehicle
97 = Physical/mental impairment – no details
98 = Other physical/mental impairment
99 = Unknown physical/mental condition

7. Driver 2 Actions/Factors Relating to Crash/Incident (VA PAR%Variable 17/18)
Reductionists will code this for crashes and near-crashes only for each vehicle immediately surrounding the subject vehicle.

0 = None
1 = Exceeded speed limit
2 = Inattentive or distracted (coded in previous variable)
3 = Exceeded safe speed but not speed limit
4 = Driving slowly: below speed limit
5 = Driving slowly in relation to other traffic: not below speed limit
6 = Illegal passing (i.e., across double line)
7 = Passing on right
8 = Other improper or unsafe passing
9 = Cutting in, too close in front of other vehicle
10 = Cutting in, too close behind other vehicle
11 = Making turn from wrong lane (e.g., across lanes)
12 = Did not see other vehicle during lane change or merge
13 = Driving in other vehicle’s blind zone
14 = Aggressive driving, specific, directed menacing actions
15 = Aggressive driving, other, i.e., reckless driving without directed
menacing actions
16 = Wrong side of road, not overtaking
17 = Following too close
18 = Failed to signal, or improper signal
19 = Improper turn: wide right turn
20 = Improper turn: cut corner on left turn
21 = Other improper turning
22 = Improper backing, did not see
23 = Improper backing, other
24 = Improper start from parked position
25 = Disregarded officer or watchman
26 = Signal violation, apparently did not see signal
27 = Signal violation, intentionally ran red light
28 = Signal violation, tried to beat signal change
29 = Stop sign violation, apparently did not see stop sign
30 = Stop sign violation, intentionally ran stop sign at speed
31 = Stop sign violation, “rolling stop”
32 = Other sign (e.g., Yield) violation, apparently did not see sign
33 = Other sign (e.g., Yield) violation, intentionally disregarded
34 = Other sign violation
35 = Non-signed crossing violation (e.g., driveway entering roadway)
36 = Right-of-way error in relation to other vehicle or person, apparent
recognition failure (e.g., did not see other vehicle)
37 = Right-of-way error in relation to other vehicle or person, apparent
decision failure (i.e., did see other vehicle prior to action but
misjudged gap)
38 = Right-of-way error in relation to other vehicle or person, other or
unknown cause
39 = Sudden or improper stopping on roadway
40 = Parking in improper or dangerous location, e.g., shoulder of
Interstate
41 = Failure to signal with other violations or unsafe actions
42 = Failure to signal, without other violations or unsafe actions
43 = Speeding or other unsafe actions in work zone
44 = Failure to dim headlights
45 = Driving without lights or insufficient lights
46 = Avoiding pedestrian
47 = Avoiding other vehicle
48 = Avoiding animal
49 = Apparent unfamiliarity with roadway
50 = Apparent unfamiliarity with vehicle, e.g., displays and controls
51 = Apparent general inexperience driving
52 = Use of cruise control contributed to late braking
53 = Other, specify