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A P P E N D I X D Project 7 and Project 8 Environmental Data Dictionary Event Variables the event should be considered a one- or two-vehicle event. Consider the event a two-vehicle event if the crash resulting Driver ID from the incident would probably have involved two vehicles or Enter the driver ID (from Slacker Tool) in the following for- if either driver's maneuvers were influenced by the presence of mat 00##. the other vehicle (e.g., if DV1 maneuvered to avoid V2). Con- sider the event a one-vehicle event if the presence of other vehi- cles presented no immediate threat and had no effect on DV1's Date maneuvers or behaviors. Enter the date on which the event occurred in the following format: mm/dd/yyyy. Vehicle/Nonmotorist 2 Type 00a = Not applicable (baseline epoch). Time 00b = Not applicable (single-vehicle event, no object). Enter the GMT time at the point of the trigger in the follow- 01 = Automobile. ing format: hh:mm AM/PM. If the time is obviously wrong 02 = Van (minivan or standard van). (e.g., it says 10:00 PM but it is daylight), write "time is wrong" 03 = Pickup truck. in the text box. 04 = SUV (includes Jeep). 05 = School bus. 06 = Transit bus. Day of Week 07 = Greyhound bus. Using a calendar, enter the day of week on which the event 08 = Conversion bus. occurred. 09 = Single-unit straight truck: multistop/step van. 10 = Single-unit straight truck: box. 11 = Single-unit straight truck: dump. Vehicles/Nonmotorists Involved 12 = Single-unit straight truck: garbage/recycling. 00 = Not applicable (baseline epoch). 13 = Single-unit straight truck: concrete mixer. 01 = 1 vehicle (subject vehicle only or subject vehicle + 14 = Single-unit straight truck: beverage. object). 15 = Single-unit straight truck: flatbed. 02 = 2 vehicles. 16 = Single-unit straight truck: tow truck. 03 = 3 vehicles. 17 = Single-unit straight truck: other. 04 = 4 or more vehicles. 18 = Single-unit straight truck: unknown. 05 = Subject vehicle + pedestrian. 19 = Straight truck + trailer. 06 = Subject vehicle + pedalcyclist. 20 = Tractor-trailer: cab only. 07 = Subject vehicle + animal. 21 = Tractor-trailer: cab + trailer. 08 = Other. 22 = Tractor-trailer: flatbed. 23 = Tractor-trailer: tank. Note: For some events (e.g., those involving transient encroach- 24 = Tractor-trailer: car carrier. ment into an oncoming lane), it is difficult to decide whether 25 = Tractor-trailer: livestock. 123

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124 26 = Tractor-trailer: lowboy trailer. 16 = Boulder. 27 = Tractor-trailer: dump trailer. 17 = Loading dock. 28 = Tractor-trailer: multiple trailers. 18 = Loading equipment (e.g., forklift or pallets). 29 = Tractor-trailer: multiple trailers, grain. 19 = Cargo. 30 = Tractor-trailer: other. 31 = Other large construction equipment. Overhanging Objects (Only If Struck or Potentially 32 = Ambulance. Struck by Top of Truck or Trailer) 33 = Fire truck. 34 = Motorcycle or moped. 20 = Tree branch. 35 = Police car. 21 = Overhanging part of sign or post. 36 = Vehicle pulling trailer (other than tractor-trailer). 22 = Bridge/overpass. 37 = Other vehicle type. 23 = Building. 38 = Pedestrian. 24 = Telephone wires. 39 = Pedalcyclist. 40 = Deer. 41 = Other animal. Nonfixed Objects 42 = Object (single-vehicle event with relevant object). 25 = Vehicle parts, including tire parts. 43 = Unknown. 26 = Spilled cargo. 27 = Dead animal in roadway. Note: Highly abridged version of GES V5, body type; codes 28 = Broken tree limbs or other tree/shrub parts. above do not match GES codes. 29 = Trash/debris. 30 = Construction barrel. Relevant Object 31 = Construction cone. Choose the most relevant object (i.e., one that was struck in a crash or that constituted a crash threat) for near crashes and Other crash-relevant conflicts. 98 = Other. 99 = Unknown object hit. 00a = Not applicable (baseline epoch). 00b = Not applicable (single-vehicle event, no relevant Note: GES A06, first harmful event. Options in italics are not object; e.g., shoulder only). A06 codes. 00c = Not applicable (multivehicle event, pedestrian, ani- mal, etc.). 01 = Parked motor vehicle. Vehicle/Nonmotorist 2 Position (in Relation to V1) The vehicle in Figure D.1 represents the subject vehicle (V1, Fixed Objects the truck). The relative position of Vehicle 2 (in relation to 02 = Building. V1) is coded for the time in which the critical event occurs 03 = Impact attenuator/crash cushion. (i.e., the event creating the crash risk). Vehicles in the adja- 04 = Bridge structure (e.g., abutment). cent left lane are coded J, I, H, or G, depending on their posi- 05 = Guardrail. tion. Vehicles in the adjacent right lane are coded B, C, D, or 06 = Concrete traffic barrier or other longitudinal barrier (e.g., Jersey barrier). 07 = Post, pole, or support (e.g., sign or light). Front 07a = Mailbox. J A B 08 = Culvert/ditch/edge of road. I C 09 = Curb. 10 = Embankment. 11 = Fence. H D 12 = Wall. 13 = Fire hydrant. 14 = Shrubbery or bush. G F E 15 = Tree (not overhang; see below). Rear Figure D.1. Vehicle diagram.

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125 E, depending on their position. Also code the position of ani- Environmental Variables mals, pedestrians, pedalcyclists, and objects. Environmental variables are coded at the time of the trigger. 00a = Not applicable (baseline epoch). 00b = Not applicable (single-vehicle event, no object). Light Condition K = Top of vehicle. 01 = Daylight. 02 = Dark. Driver/Vehicle 1 variables 03 = Dark but lighted. Driver/Vehicle 1 (DV1) is always the study subject driver/ 04 = Dawn. vehicle (i.e., the truck or truck driver). 05 = Dusk. 09 = Unknown. Driver Seat Belt Worn? Note: GES A19. 00 = No. 01 = Yes. 02 = Unknown. Weather 01 = No adverse conditions. Possible to Do Observer Rating of Drowsiness? 02 = Rain. 03 = Sleet. 00 = Yes. 04 = Snow. 01 = No, wearing sunglasses. 05 = Fog. 02 = No, not enough video. 06 = Rain and fog. 03 = No, cannot see driver's eyes. 07 = Sleet and fog. 08 = Other (smog, smoke, sand/dust, crosswind, hail). Driver 1 Vision Obscured 09 = Unknown. 00 = No obstruction. Comment: GES A20. 01 = Rain, snow, smoke, sand, dust. 02 = Reflected glare, sunlight, headlights. 03 = Curve or hill. Roadway Surface Condition 04 = Building, billboard, or other design features (includes 01 = Dry. signs, embankment). 02 = Wet. 05 = Trees, crops, vegetation 03 = Snow or slush. 06 = Moving vehicle (including load). 04 = Ice. 07 = Parked vehicle. 05 = Sand, oil, dirt. 08 = Splash or spray of passing vehicle or any other vehicle. 08 = Other. 09 = Inadequate defrost or defog system. 09 = Unknown. 10 = Inadequate lighting system (includes vehicle or object in dark area). Comment: GES A15. 11 = Obstruction interior to vehicle. 12 = Mirrors. Relationship to Junction 13 = Head restraints. 14 = Broken or improperly cleaned windshield. 00 = Nonjunction. 15 = Fog. 01 = Intersection. 16 = Other vehicle or object in blind spot. 02 = Intersection related. 97 = Vision obscured, no details. 03 = Driveway, alley access, etc. 98 = Other obstruction. 03a = Parking lot. 99 = Unknown whether vision was obstructed. 04 = Entrance/exit ramp. 05 = Rail grade crossing. Note: GES Variable D4. Element 16 added because of relevance 06 = On a bridge. to large trucks. 07 = Crossover related.

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126 08 = Other. 02b = Grade down. 09 = Unknown. 03 = Hillcrest. 04 = Sag. Comment: GES variable A09. Baseline epoch coded at time of trigger. Note: GES V A14, with expansion of grade choices. Coded in relation to subject vehicle; baseline epoch coded at time of trigger. Trafficway Flow 00 = Not physically divided (center two-way left-turn Traffic Density lane). 01 = Not physically divided (two-way trafficway). Code the traffic density for the time before the precrash event. 02 = Divided (median strip or barrier). 03 = One-way trafficway. 01 = LOS A: Free flow. (Individual users are virtually unaf- 09 = Unknown. fected by the presence of others in the traffic stream. Free- dom to select desired speeds and to maneuver within the Note: GES variable V A11. Coded in relation to subject vehi- traffic stream is extremely high. The general level of com- cle; baseline epoch coded at time of trigger. fort and convenience provided to the motorist, passenger, or pedestrian is excellent.) 02 = LOS B: Flow with some restrictions. (In the range of sta- Number of Travel Lanes ble traffic flow, but the presence of other users in the traffic 01 = 1. stream begins to be noticeable. Freedom to select desired 02 = 2. speeds is relatively unaffected, but there is a slight decline 03 = 3. in the freedom to maneuver within the traffic stream from 04 = 4. LOS A because the presence of others in the traffic stream 05 = 5. begins to affect individual behavior.) 06 = 6. 03 = LOS C: Stable flow; maneuverability and speed are 07 = 7+. more restricted. (Traffic flow is in the stable range but is 09 = Unknown. beginning to enter the range of flow in which the operation of individual users becomes significantly affected by interac- Note: GES V A12. Per GES, if road is divided, only lanes in tions with others in the traffic stream. The selection of speed travel direction are counted. If undivided, all lanes are counted. is now affected by the presence of others, and maneuvering Coded in relation to subject vehicle; baseline epoch coded at within the traffic stream requires substantial vigilance on the time of trigger. Count all contiguous lanes at the time and part of the user. The general level of comfort and conven- location of the incident; for example, include entrance or exit ience declines noticeably at this level.) lanes if contiguous. Do not include lanes if blocked by cones 04 = LOS D: Unstable flow; temporary restrictions substan- or barrels. tially slow the driver. (This category represents high-density but stable traffic flow. Speed and freedom to maneuver are severely restricted, and the driver or pedestrian experiences Roadway Alignment a generally poor level of comfort and convenience. Small 01 = Straight. increases in traffic flow generally cause operational problems 02a = Curve right. at this level.) 02b = Curve left. 05 = LOS E: Flow is unstable; vehicles are unable to pass, 09 = Unknown. temporary stoppages, etc. (Operating conditions are at or near capacity level. All speeds are reduced to a low but rel- Note: GES V A13, with expansion of curve choices. Coded in atively uniform value. Freedom to maneuver within the relation to subject vehicle; baseline epoch coded at time of traffic stream is extremely difficult and is generally accom- trigger. plished by forcing a vehicle or pedestrian to give way to accommodate such maneuvers. Comfort and convenience levels are extremely poor, and driver or pedestrian frustra- Roadway Profile tion is generally high. Operations at this level are usually 01 = Level (or unknown). unstable because small increases in flow or minor pertur- 02a = Grade up. bations within the traffic stream will cause breakdowns.)

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127 06 = LOS F: Forced traffic flow condition with low speeds Note: Any area with one or more traffic cones, barrels, and so and traffic volumes that are below capacity; queues form forth is considered to be a construction zone. in particular locations. (This condition exists whenever the amount of traffic approaching a point exceeds the Truck Pre-Event Speed amount that can traverse the point. Queues form behind such locations. Operations within the queue are charac- Note: The pre-event speed is coded for the period just before terized by stop-and-go waves and are extremely unstable. the occurrence of the critical event or just before any avoidance Vehicles may progress at reasonable speeds for several maneuver or both. For example, when braking is involved, hundred feet or more and then be required to stop in a the pre-event speed is the speed just before the beginning of cyclic manner. LOS F is used to describe operating condi- braking. If there is no avoidance maneuver, enter the speed at tions within the queue, as well as the point of the break- the time of the trigger. down. In many cases, operating conditions of vehicles or pedestrians discharged from the queue may be quite good. 999 = Unknown. Nevertheless, it is the point at which arrival flow exceeds discharge flow, which causes the queue to form. LOS F is an appropriate designation for such points.) General Variables 09 = Unknown/unable to determine. Event Comments Note: This text variable permits analysts to provide any com- Construction Zone Related ments on the event, including information not captured 00 = Not construction zone related (or unknown). by data variables, assumptions made about the event affect- 01 = Construction zone (occurred in zone). ing coding, and coding issues that arose. Ordinarily this 02 = Construction zone related (occurred in approach or will not contain information that is captured by the coded otherwise related to zone). variables.