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Safety Evaluation of Permanent Raised Pavement Markers (2004) / Chapter Skim
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Appendix A - Details of Calibrated Safety Performance Functions
Pages 55-60

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From page 55...
... • α f = factor applied to the calibrated model to predict for a crash type other than that used for the model calibration. • AADT = annual average daily traffic.
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From page 56...
... NA NA NA 0.1720 (0.0956) k 3.2 2.2 3.5 3.1 Model parameters f k f k f k f k Total 1.000 3.2 1.000 2.2 1.000 3.5 1.000 3.1 Fatal and injury 0.195 4.3 0.430 2.2 0.738 3.4 0.262 1.9 Daytime 0.578 2.6 0.656 1.6 0.600 3.7 0.479 3.4 Daytime fatal and injury 0.101 3.8 0.298 2.1 0.468 3.2 0.148 2.2 Nighttime 0.422 3.1 0.344 2.8 0.400 2.2 0.521 2.5 Nighttime fatal and injury 0.094 2.6 0.131 2.0 0.270 2.9 0.135 1.6 Dry 0.657 2.7 0.729 1.9 0.590 3.1 0.690 2.9 Wet 0.337 2.0 0.270 1.8 0.390 7.4 0.247 1.7 Head-on 0.067 3.0 0.064 2.2 Sample size too small 0.031 3.1 Guidance-related 0.209 3.6 0.045 0.7 0.368 2.5 TABLE A-2 Pennsylvania two-lane roadways: annual factors Annual Factors Total Fatal and Injury Daytime Daytime Fatal and Injury Nighttime Nighttime Fatal and Injury Dry Wet HeadOn GuidanceRelated 1991 0.94 1.00 0.84 0.81 1.09 1.21 1.01 0.84 0.75 1.05 1992 1.00 1.17 0.88 1.04 1.17 1.30 0.92 1.19 0.72 0.96 1993 1.00 1.01 0.99 0.84 1.02 1.18 1.00 1.00 0.89 0.93 1994 0.84 0.84 0.80 0.80 0.89 0.99 0.83 0.83 1.01 0.98 1995 0.98 1.03 1.05 1.05 0.88 1.00 1.02 0.91 1.08 1.14 1996 0.97 0.87 0.95 0.79 0.99 0.94 0.95 0.99 0.69 1.06 1997 0.97 0.85 1.02 0.78 0.90 0.93 0.87 1.18 1.30 1.12 1998 0.97 0.85 1.02 1.01 0.90 0.68 1.05 0.81 1.14 0.82 1999 1.07 0.94 1.16 1.37 0.96 0.49 1.15 0.92 1.12 1.10 2000 1.19 1.35 1.21 1.41 1.16 1.29 1.13 1.25 1.19 0.76 TABLE A-3 New Jersey two-lane roadways: annual factors Annual Factors Total Fatal and Injury Daytime Daytime Fatal and Injury Nighttime Nighttime Fatal and Injury Dry Wet Head-On 1991 0.89 0.91 0.92 0.94 0.84 0.84 0.91 0.84 0.89 1992 0.93 0.91 0.90 0.88 0.98 0.99 0.91 0.98 0.94 1993 PRPM Implementation Year 1994 1.11 1.05 1.11 1.05 1.11 1.05 1.11 1.11 1.12 1995 1.05 0.95 1.05 0.95 1.05 0.95 1.05 1.05 1.05 1996 PRPM Implementation Year 1997 1.14 0.89 1.14 0.89 1.14 0.90 1.14 1.14 1.14 1998 1.00 0.85 1.00 0.85 1.00 0.85 1.00 1.00 1.01 NOTE: It was not possible to extract guidance-related crashes from the New Jersey database.
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From page 57...
... NA NA NA 0.3194 (0.0774) k 2.3 2.9 3.2 2.3 Model parameters f k f k f k f k Total 1.000 2.3 1.000 2.9 1.000 3.2 1.000 2.3 Fatal and injury 0.131 2.9 0.444 2.6 0.318 3.5 0.250 2.3 Daytime 0.598 1.9 0.570 2.6 0.618 2.7 0.652 2.4 Daytime fatal and injury 0.075 2.6 0.263 2.0 0.199 3.1 0.151 2.3 Nighttime 0.402 2.3 0.430 3.3 0.382 4.0 0.348 2.0 Nighttime fatal and injury 0.055 4.0 0.181 3.6 0.120 4.3 0.099 2.4 Dry 0.581 2.2 0.503 2.2 0.666 4.2 0.604 2.4 Wet 0.414 1.3 0.480 2.9 0.334 1.6 0.396 1.7 Guidance-related 0.221 1.6 0.017 0.9 0.476 3.0 0.606 2.0 1Data for Pennsylvania and Missouri are for one direction of travel only.
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From page 58...
... A-4 TABLE A-7 Pennsylvania four-lane freeways: annual factors Annual Factors Total Fatal and Injury Daytime Daytime Fatal and Injury Nighttime Nighttime Fatal and Injury Dry Wet Guidance-Related 1991 0.92 0.92 0.92 0.92 0.92 0.92 0.98 0.83 0.92 1992 0.92 0.92 0.92 0.92 0.92 0.92 0.98 0.83 0.92 1993 1.02 1.02 1.02 1.02 1.02 1.02 0.96 1.11 1.02 1994 1.02 1.02 1.02 1.02 1.02 1.02 0.96 1.11 1.02 1995 1.02 1.02 1.02 1.02 1.02 1.02 0.96 1.11 1.02 1996 1.02 1.02 1.02 1.02 1.02 1.02 0.96 1.11 1.02 1997 0.95 0.95 0.95 0.95 0.95 0.95 1.01 0.85 0.95 1998 0.95 0.95 0.95 0.95 0.95 0.95 1.01 0.85 0.95 1999 0.95 0.95 0.95 0.95 0.95 0.95 1.01 0.85 0.95 2000 0.95 0.95 0.95 0.95 0.95 0.95 1.01 0.85 0.95 TABLE A-8 New York four-lane freeways: annual factors Annual Factors Total Fatal and Injury Daytime Daytime Fatal and Injury Nighttime Nighttime Fatal and Injury Dry Wet Guidance-Related 1993 0.42 0.66 0.46 0.72 0.37 0.56 0.41 0.43 0.51 1994 0.46 0.71 0.46 0.66 0.46 0.79 0.44 0.47 0.31 1995 0.60 0.86 0.66 0.92 0.52 0.77 0.62 0.56 0.41 1996 0.66 0.95 0.65 0.87 0.67 1.06 0.58 0.73 0.91 1997 0.82 1.08 0.87 1.09 0.76 1.05 0.72 0.95 1.11 1998 PRPM Implementation Year 1999 1.04 0.66 0.99 0.66 1.11 0.67 1.15 0.94 0.50 2000 1.21 0.63 1.19 0.65 1.24 0.61 1.23 1.17 1.30 2001 1.42 0.76 1.37 0.86 1.48 0.63 0.78 2.09 1.21 TABLE A-9 Missouri four-lane freeway: annual factors Annual Factors Total Fatal and Injury Daytime Daytime Fatal and Injury Nighttime Nighttime Fatal and Injury Dry Wet Guidance-Related 1991 0.86 0.94 0.81 0.90 0.94 0.99 0.87 0.84 0.91 1992 0.74 0.77 0.73 0.76 0.76 0.77 0.83 0.57 0.71 1993 0.97 0.95 0.93 0.90 1.04 1.03 0.90 1.11 1.01 1994 0.96 0.96 0.93 0.90 1.02 1.06 1.04 0.80 0.94 1995 0.93 0.89 0.89 0.85 0.99 0.94 0.97 0.86 0.90 1996 1.05 1.03 1.07 1.04 1.02 1.01 1.00 1.15 1.03 1997 1.01 1.07 1.05 1.12 0.95 0.97 0.98 1.08 1.08 1998 1.05 1.02 1.11 1.04 0.95 0.97 1.01 1.11 1.03 1999 1.11 1.07 1.27 1.25 0.86 0.76 1.07 1.20 1.02 2000 1.01 0.98 1.00 1.01 1.02 0.91 0.97 1.08 0.99 2001 0.95 0.87 1.01 0.93 0.86 0.76 0.92 1.02 0.94
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From page 59...
... AADT is for both directions. Annual Factors Total Fatal and Injury Daytime Daytime Fatal and Injury Nighttime Nighttime Fatal and Injury Dry Wet Guidance-Related 1991 0.76 0.86 0.78 0.82 0.72 0.93 0.75 0.77 0.88 1992 0.76 0.86 0.78 0.82 0.72 0.93 0.75 0.77 0.88 1993 0.61 0.60 0.61 0.65 0.60 0.50 0.58 0.68 0.63 1994 0.61 0.60 0.61 0.65 0.60 0.50 0.58 0.68 0.63 1995 0.61 0.60 0.61 0.65 0.60 0.50 0.58 0.68 0.63 1996 0.61 0.60 0.61 0.65 0.60 0.50 0.58 0.68 0.63 1997 0.72 0.62 0.68 0.54 0.78 0.76 0.81 0.54 0.49 1998 0.72 0.62 0.68 0.54 0.78 0.76 0.81 0.54 0.49 1999 0.72 0.62 0.68 0.54 0.78 0.76 0.81 0.54 0.49 2000 0.72 0.62 0.68 0.54 0.78 0.76 0.81 0.54 0.49 TABLE A-11 Safety performance functions for fourlane divided expressways TABLE A-12 Pennsylvania four-lane divided expressways: annual factors
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From page 60...
... A-6 TABLE A-13 Wisconsin four-lane divided expressways: annual factors Annual Factors Total Fatal and Injury Daytime Daytime Fatal and Injury Nighttime Nighttime Fatal and Injury Dry Wet Guidance-Related 1994 0.77 0.65 0.69 0.64 0.95 0.67 0.81 0.65 1.05 1995 0.69 0.60 0.69 0.66 0.69 0.52 0.76 0.48 0.99 1996 1.00 1.10 1.00 0.94 1.00 1.29 0.98 1.08 0.89 1997 1.14 1.18 1.20 1.28 1.03 1.07 1.06 1.41 0.91 1998 1.28 1.35 1.31 1.35 1.23 1.35 1.29 1.27 1.05 1999 PRPM Implementation Year 2000 1.42 1.71 1.43 1.70 1.43 1.72 1.43 1.43 1.42
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Key Terms

  • safety performance
  • nighttime fatal
  • performance functions
  • daytime fatal
  • total fatal

  • factors total
  • dry wet
  • nighttime nighttime
  • daytime daytime
  • rolling terrain

  • divided expressways
  • annual average
  • flat terrain
  • model form
  • cedure documented

  • estimated using
  • average daily
  • traffic volumes
  • mance functions
  • daily traffic

  • expected safety
  • factors annual
  • na na
  • prpm implementation
  • model parameters

  • sample size
  • calibrated model
  • lane divided
  • calibrated parameter
  • compared data


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