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

The Kentucky Traffic Safety Data Service (KTSDS) is a program of the Kentucky Transportation Center.
176 Raymond Building, University of Kentucky, Lexington KY 40506.

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