Traffic Control Devices and Measures for Deterring Wrong-Way Movements (2018) / Chapter Skim
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Pages 5-23
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5 This chapter provides information regarding the methodologies used to develop a divided highway multistate crash dataset. This dataset was used to determine the characteristics of wrong-way crashes and wrong-way drivers.
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6 research team found that 255 wrong-way crashes occurred on high-speed divided highways. Next, researchers reviewed the crash diagrams and associated narratives for the wrong-way driving crashes that occurred on high-speed divided highways.
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7 type variable to remove divided non-freeway facilities with two-way left-turn lanes or other miscellaneous median lanes (e.g., bus lanes)
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8 shape file consists of geolocation markers every 1/10 of a mile along California highways. Similar to the instance of defining segments with wrong-way crashes, the research team performed an analysis to match the HSIS road inventory table to the referenced shape file.
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9 Pe rc en ta ge o f W ro ng -W ay C ra sh es Figure 1. Percentage of wrong-way crashes by day of the week.
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10 75 percent of the wrong-way crashes that occurred on highspeed divided highways with four lanes (two in each direction) and a grass median.
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Figure 2. MUTCD median width at wrong-way entry points with median openings by state (n = 277)
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12 of the wrong-way drivers, while males represented two-thirds of the wrong-way drivers. Figure 5 shows the age of the wrong-way drivers on highspeed divided highways by state and overall.
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13 Figure 5. Age of wrong-way drivers on high-speed divided highways by state and overall.
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14 no history of wrong-way crashes. Because of the different approach to developing the dataset, the method of analysis was modified slightly.
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15 that crashes attributed to wrong-way maneuvers at ramps, median openings only (no intersecting roadway) , and crossing the median were relatively small (8 percent, 7 percent, and less than 1 percent, respectively)
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16 Expanded Variable Name Short Variable Name Variable Description Type of Intersection Control IntersectionTC_TTI Type of control at intersection of minor and major roadways. 1 is none; 2 is STOP signs; 3 is YIELD signs; 4 is traffic signal.
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17 The probability of wrong-way crashes was used as the response variable in all the analyses. The datasets were made up of roughly a 50/50 split between sites with a history of wrong-way crashes and randomly selected control sites.
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18 point was known. Although not included in the modeling process, researchers believe this result would also be true for a DO NOT ENTER sign placed in the median on the far right side.
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19 The presence of either the near right outside ONE WAY sign or near left inside ONE WAY sign was associated with a reduction in the risk of nighttime wrong-way crashes. The odds of nighttime wrong-way crashes reduced by a factor of 0.487 at locations with either of these signs compared to locations without these signs (exp(−0.719)
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20 Given the small set of model covariates and the small sample of urban sites from California (n = 19) , researchers speculate that there was a confounding, unaccounted factor that produced the increased risk.
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21 Figure 9. Type of control in the median opening -- urban sites.
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22 The presence of a stop or yield line on the minor approach was also associated with a more significant reduction in the risk of nighttime wrong-way crashes. The odds of nighttime wrong-way crashes at locations with a stop or yield line on the minor approach were 0.495 times as large as the odds of nighttime wrong-way crashes at locations without this pavement marking (exp(−0.704)
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23 level of confidence desired, the increase in wrong-way crash log-odds associated with median width should be clearly identifiable for median widths of about 50 ft or wider. Summary This chapter documented the exploratory and statistical analyses of wrong-way crashes on high-speed divided highways.
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