HW 7 a HSM Practitioners Guider for Two

HW 7 a: HSM Practitioner’s Guider for Two. Lane Rural Highways Workshop Exercise II – US 52 from Sageville to Holy Cross – Prediction of Safety Performance for Curves and Comparison to Substantive Safety Performance 5 -1

Exercise II – US 52 from Sageville to Holy Cross Outcomes: ► Identify Curve Crashes ► Predict crash frequency for base conditions using SPF Base Model ► Apply CMFs for existing conditions to predict the safety performance of Curves ► Compare predicted safety performance of Curves to actual safety performance 5 -2

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1996 - 2000 5 -4

Exercise II – US 52 from Sageville to Holy Cross Geometric Information: § Length: § ADT: § Lane Width: § Shoulders: 13. 0 miles 2, 500 11 feet Paved 0 feet Gravel 4 feet § Hazard Rating: 5 § Driveways: 91 (none on curves) §Total Length of Curves = 4, 826 ft or 0. 914 mi Traffic Volume (AADT): 2, 500 vehicles per day 5 -5

Exercise II – US 52 from Sageville to Holy Cross Geometric Information: Curves - no spirals Curve # Delta Radius Length S. V. fo e 1 104 deg 670. 15 ft 1, 225. 5 ft 0. 01 2 - “A” 104 deg 33’ 836. 6 ft 1162 ft 0. 00 3 - “B” 63 deg 56’ 477. 5 ft 532. 8 ft 0. 00 4 - “C” 67 deg 04’ 477. 5 ft 558. 9 ft 0. 01 5 - “D” 42 deg 15’ 477. 5 ft 352 ft 0. 01 6 - “E” 62 deg 58’ 477. 5 ft 524. 8 ft 0. 02 7 - “F” 28 deg 10’ 955 ft 469. 4 ft 0. 01 Total Curve Lengths = 4, 826 feet = 0. 914 mi 5 -6

Exercise II: US 52 from Sageville to Holy Cross – Segments/Grade/Curves Crashes by location LOCATION On Roadway Segments NUMBER 63 Within Intersection 16 Intersection Related 1 On-Grades 3 On Curves 39 Total 122 5 -7

Exercise II – US 52 from Sageville to Holy Cross From the US 52 corridor crash information, perform the following: 1. (a) Identify Curve Crashes and (b) Determine Predicted Crash Frequency for base conditions for the 7 Horizontal Curves (crashes/year) 2. Compute CMF 3 r and CMF 4 r for the 7 horizontal curves on US 52. 3. Apply appropriate CMFs to determine the Predicted Crash Frequency for existing conditions for the curved sections (crashes/year) 4. Compare the Actual Crash History (Substantive Performance) to the Predicted Crash Frequency (crashes/yr) 5 -8

Exercise II: US 52 from Sageville to Holy Cross – Segments/Grade/Curves 1 (a): Identify Crashes on Curves LOCATION On Roadway Segments NUMBER 63 Within Intersection 16 Intersection Related 1 On-Grades 3 On Curves 39 Total 122 5 -9

Exercise II – US 52 from Sageville to Holy Cross 1 (b). Compute the Predicted Crashes on Horizontal Curves for base conditions: For the 7 Horizontal Curves: Nspf-rs curves 1 -7 = (ADT) (Lcurve)(365)(10 -6)e-0. 312 = (2, 500)(Lcurve x)(365)(10 -6)e-0. 312 5 -10

Exercise II – US 52 Curves Nspf-rs = (AADTn) (L) (365) (10 -6) e-0. 3. 12 1. (b): Curve Information: No Spirals Curve Radius (ft) Lc (mi) Spiral (S) S. V. Nspf-rs 1 670 1, 226 0. 232 0 0. 01 0. 155 2 - “A” 837 1, 162 0. 220 0 0. 00 0. 147 3 - “B” 478 533 0. 101 0 0. 067 4 - “C” 478 559 0. 106 0 0. 01 0. 071 5 - “D” 478 352 0. 067 0 0. 01 0. 045 6 - “E” 478 525 0. 099 0 0. 02 0. 066 7 - “F” 955 469 0. 089 0 0. 01 0. 059 Total: 0. 914 mi 5 -11

Exercise II – US 52 from Sageville to Holy Cross q. Use Worksheet Exercise II 2. Compute CMF 3 r and CMF 4 r for the 7 horizontal curves on US 52. 3. Apply appropriate CMFs to determine the Predicted Crash Frequency for existing conditions for the curved sections (crashes/year) a. Apply appropriate CMFs to the 7 Horizontal Curves (Use values for CMF 1 r CMF 2 r & CMF 10 r from Exercise I): Npredicted-rs curves = Nspf-rs curves (CMF 1 r x CMF 2 r x CMF 3 r x CMF 4 r x CMF 10 r) 5 -12

Exercise II – US 52 Curves Nspf-rs = (AADTn) (L) (365) (10 -6) e-0. 3. 12 Eqs: 10 -14, 15, & 16 5 -13

Exercise II – US 52 from Sageville to Holy Cross 4. Compare the Actual Crash Frequency per year to the Predicted Crash Frequency for the curves Actual Curve crashes = 39 / 5 years = _____ crashes per year Npredicted-rs curves = _____ crashes per year 5 -14

Exercise II – US 52 from Sageville to Holy Cross Outcomes: ► Identified Curve Crashes ► Predicted crash frequency for base conditions using SPF Base Model ► Applied CMFs for existing conditions to predict the safety performance of Curves ► Compared predicted safety performance of Curves to actual safety performance 5 -15

Exercise I: US 52 from Sageville to Holy Cross Questions and Discussion: 5 -16