Project Info

Project Request Date: 5/14/2018
Project Requested By: William Madden – AECOM
Principle Investigator: Eric Green

Project Write-up

Initial Request:

“Safety Performance Function for KY 207 in Greenup County between the KY 67 interchange and KY 693 Departure intersection, MP 10.93 to MP 15.88. This is for KYTC project number 09-8509.00.”

 

Final Rural Two-Lane SPF and Adjustment Factors

Base Conditions

9’ lanes, 3’ shoulders, Horizontal curvature= Class A, Grade= Class A, no median, no intersections

 

Sample 3119 100-200 intersections*
Length 215.8455 100-200 miles*
Crashes 854 300 crashes per year*
R2 0.515857 Higher values preferred
CDP 13.5941 Less than 5%
MACD 43.40788 Smaller values preferred
MAD 0.355154 Smaller values preferred
Theta 1.531877 Higher values preferred
Alpha -4.49214 (Intercept) zvalue= 8.77117005270637e-29
Beta 0.844042 lnADT zvalue= 6.2937196537382e-51
StdErr 0.273624
AIC 3581.527

 

Lane width AF (Modified from HSM)

Lane Width (ft) AADT <400 AADT 400-2000 AADT>2000
9 or less (base) 1 1 1
10 0.97 1.02+.000175*(AADT-400)/ 1.05+.000281*(AADT-400) 0.87
11 0.96 1.01+.000025*(AADT-400)/ 1.05+.000281*(AADT-400) 0.7
12 or more 0.95 1/(1.05+.000281*(AADT-400) 0.67

 

Shoulder Width AF (http://www.cmfclearinghouse.org/study_detail.cfm?stid=338)

Shoulder Width AF Crash Severity Roadway Type Area
0 1.145 All Two-Lane Rural
1 1.12 All Two-Lane Rural
2 1.03 All Two-Lane Rural
3 1 All Two-Lane Rural
4 0.975 All Two-Lane Rural
5 0.945 All Two-Lane Rural
6 0.93 All Two-Lane Rural
7 0.905 All Two-Lane Rural
8 0.875 All Two-Lane Rural

 

Horizontal Curvature AF (http://www.cmfclearinghouse.org/study_detail.cfm?stid=481)

Grade AF (HSM)

Grade AF
0-3% 1
3-6% 1.1
>6% 1.16

 

Median Installation AF (http://www.cmfclearinghouse.org/detail.cfm?facid=24)

0.88

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