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From page 241... ... 243 A P P E N D I X B - D A T A B A S E D I C T I O N A R Y Database Dictionary Introduction Two master datasets were developed for NCHRP Project 17-89 – one for Static and Dynamic PTSU facilities (PTSU) and one for Bus-on-Shoulder facilities (BOS) Read the entire page →
From page 242... ... 244 Appendix A provides more specific and detailed information on how variables associated with these segmentation criteria (number of lane, lane width, etc.) were measured. Read the entire page →
From page 243... ... 245 Table B-1. NCHRP Project 17-89 Site Types Basic Freeway Segment (BFS) Read the entire page →
From page 244... ... 246 Applicability: All County Variable name: County Format: XXXX Type: Character Method of measurement: Agency-provided Values: Ohio DOT's three letter abbreviation for a county in Ohio, value of "none" in other states. Ohio facilities use county-based mileposts Applicability: All Route Variable name: Route Format: XXX Type: Integer Method of measurement: General knowledge Values: A state's numerical designation of the route. Read the entire page →
From page 245... ... 247 The three comparison site types are indistinguishable from one another by inspection alone; the differentiation occurs because each comparison site will be located in the same metropolitan area as a PTSU site. A comparison site located in the same metropolitan area as a BOS site, for example, will be designated as a BOS comparison site. Read the entire page →
From page 246... ... 248 Method of measurement: Observed in Google Earth Values: Indicates the number of managed lanes, such as high occupancy vehicle (HOV) or high occupancy toll (HOT) Read the entire page →
From page 247... ... 249 Opening Date Known Variable name: OpeningKnown Format: XXXXX Type: Boolean Method of measurement: Assigned by research team based on confidence in prior variable Values: If the opening date is known with certainty or is more than 1 year prior to the start of the crash data analysis period, this variable will be set to TRUE. Acceptable values are True and False Applicability: S-,D-PTSU This variable is not included in the BOS database Conversion Date Variable name: Conversion Format: YYYY-MM-DD Type: Integer-Integer-Integer Method of measurement: Agency-provided. Read the entire page →
From page 248... ... 250 Dimensional Units: Degree, minutes, and seconds of latitude and longitude Values: The first portion of this field, prior to the comma, represents the degrees, minutes, and seconds of latitude north of the equator of a site's starting point. The second portion of the field, after the comma, represents the degrees, minutes, and seconds of longitude west of the Prime Meridian of a site's starting point. Read the entire page →
From page 249... ... 251 Values: The milepost in a state's route inventory data corresponding to the end of the site. If a state provides milepost data in GIS format, the GIS file will be imported to Google Earth to enable a visual comparison to EndCoord and assignment of an EndMillepost value based on this comparison. Read the entire page →
From page 250... ... 252 Format: X.XXXX Type: Real Number Dimensional Units: Miles Method of measurement: Computed by summing the Length values of each segment in a specific speed-change lane. Often a speed change lane consists of only one segment and SCLaneLength equals Length Values: The distance between the gore point and the taper point of a speed change lane, measured along the left edge of the travelled way of the freeway Applicability: ENSCL, EXSCL Number of Lanes on Ramp Variable name: RampLanes Format: X Type: Integer Method of measurement: Observed in Google Earth Applicability: All Speed Change Lane Type, Lane 1 Variable name: SCLType1 Format: X Type: Character Method of measurement: Classification assigned by research team Values: The codes for this variable have the following meanings  A – PTSU adds from an entrance speed-change lane or drops onto an exit speed- change lane  B – PTSU is present before and after the speed-change lane. Read the entire page →
From page 251... ... 253  C – PTSU is between the rightmost general purpose lane and a parallel-style speed change lane.  D – PTSU starts or ends at the gore by a general purpose lane converting to PTSU  E – PTSU starts or ends at the gore by PTSU adding from or dropping onto the ramp. Read the entire page →
From page 252... ... 254 Figure B-4. Definitions of PTSU Transition Segment, End Areas if Taper Present Figure B-5. Read the entire page →
From page 253... ... 255 Method of measurement: Assigned by team based on opening day of facility and years of crash data used for analysis Values: The four-digit year, two-digit month, and two-digit day that is the last day of the analysis and modeling period for this project. This will typically be December 31 of a year that is five years after the year of StartDay. Read the entire page →
From page 254... ... 256 Values: The length of a curve that is within the limits of analysis site. If a curve is completely within the limits of the analysis site, CurveLenInSeg is equal to CurveLen. Read the entire page →
From page 255... ... 257 Dimensional Units: Feet Method of measurement: Computed with macros from pins dropped in Google Earth Values: The width in feet of the portion of the right shoulder used for PTSU. If the shoulder does not have a second edge line or it located at edge of pavement, RShoulderPTSU is equal to RShoulder. Read the entire page →
From page 256... ... 258 Method of measurement: Measurements with ruler tool in Google Earth Values: The length within a segment that rumble strips are present on the right shoulder. Applicability: All Length of Left Side Rumble Strips Variable name: LRumble Format: XXX Type: Real Number Dimensional Units: Feet Method of measurement: Measurements with ruler tool in Google Earth Values: The length within a segment that rumble strips are present on the left shoulder. Read the entire page →
From page 257... ... 259 Median Width Variable name: MedianWidth Format: XX.X Type: Real Number Dimensional Units: Feet Method of measurement: Computed with macros from pins dropped in Google Earth Values: The distance from the inside edge of the inside shoulder in the increasing direction of travel to the inside edge of the inside shoulder in the decreasing direction of travel. This width does not include the shoulder itself Applicability: All. Read the entire page →
From page 258... ... 260 includes the portion of a shoulder used for left side S-,D-PTSU but not the portion of a shoulder used for left side BOS. Applicability: All. Read the entire page →
From page 259... ... 261 Dimensions illustrate measurement of the following variables: 1. Right Shoulder Width 2. Read the entire page →
From page 260... ... 262 Weaving Length Variable name: WeavingLength Format: XXXX Type: Integer Method of measurement: Manually measured in Google Earth with Ruler Tool Values: The length of the weaving section in feet, measured from gore point to gore point, where a gore point is defined as the location where the edge line of the freeway and edge line of the ramp are 2 feet apart Applicability: All segments where "Weaving" = "One-Sided" Note: A number of variables that follow refer to upstream and downstream ramps, as well as ramps within a site (for speed change lane sites) Read the entire page →
From page 261... ... 263 Values: R and L Length of a transition segment that is with 800' or less from the start or end of PTSU. Read the entire page →
From page 262... ... 264 Distance to Upstream Start of PTSU Variable name: DistToStart Format: X.XX Type: Real Number Dimensional Units: Miles Method of measurement: Computed with arithmetic from other variables Values: The upstream distance from the start of the segment to the start of PTSU, measured along the left edge of the travelled way of the freeway. The distance is measured to the start of the overall PTSU facility, even if there are short intermittent sections where shoulder traffic uses a permanent auxiliary or speed change lane or is not present through an interchange. Read the entire page →
From page 263... ... 265 Sign Type Variable name: SignType Format: XXXXXX Type: Character Method of measurement: General knowledge Values: Indicates if an S-PTSU facility has static or dynamic signs Applicability: S-PTSU This variable is not included in the BOS database The next group of columns in the site data worksheet contain average values for each of the AADT variables (the site's AADT, downstream exit ramp AADT, etc.) and the number of days in each year studied, which is used to compute the average AADTs. Read the entire page →
From page 264... ... 266 Values: The proportion of a typical weekday's (Tuesday through Thursday) volume during each hour of the typical weekday within the year of HourlyYear. Read the entire page →
From page 265... ... 267 Weekend Hourly Volume Proportion, for each hour of the day Variable name: WeekendVol0 through WeekendVol23 (24 unique variables) Format: XXXX Type: Integer Values: The proportion of a typical weekend (Saturday and Sunday) Read the entire page →
From page 266... ... 268 Crash ID Variable name: CrashID Format: XXXXXXX Type: Assumed to be Integer Values: A state's unique identification number for the crash Applicability: All Route Variable name: Route Format: XXX Type: Integer Values: A state's numerical designation of the route Applicability: All Direction of Freeway Variable name: DirectionFreeway Format: XXX Type: Character Values: INC for increasing milepost direction (northbound or eastbound) or DEC for decreasing milepost direction (southbound or westbound) Read the entire page →
From page 267... ... 269 Day of Crash Variable name: Day Format: DD Type: Integer Values: The day on which the crash occurred (1 through 31) Applicability: All Hour of Crash Variable name: Hour Format: HH Type: Integer Values: The hour in which the crash occurred (0 through 23) Read the entire page →
From page 268... ... 270 Applicability: All, but was not available for all states Bus Involvement Variable name: BusInvolved Format: XXX Type: Character Values: Acceptable value of "yes" if state's crash data indicated one of the vehicles involved in the crash is a bus Applicability: BOS, BOSCOMP PTSU Open/Close Status For each direction of each PTSU facility, the research team developed a table with one row for every hour of the five-year analysis period. This table has approximately 24 x 365 x 5 = 43,800 rows. Read the entire page →
From page 269... ... 271 Example of PTSU Open/Close Status Worksheet Day Hour I‐66 EB I‐66 WB I‐85 NB … Weekday 12:00 AM 0 0 0 … Weekday 1:00 AM 0 0 0 … … … … … … Weekday 4:00 PM 0 .974 1 … … … … … … … Weekend 11:00 PM .006 .005 0 … Read the entire page →

From page 241...

... 243 A P P E N D I X B - D A T A B A S E D I C T I O N A R Y Database Dictionary Introduction Two master datasets were developed for NCHRP Project 17-89 – one for Static and Dynamic PTSU facilities (PTSU) and one for Bus-on-Shoulder facilities (BOS)