1. Results and Status of State Crash Analyses
IDS - Pool Fund
Presented to IDS Pool Fund Partners
January 18, 2005

2. Outline Crash Analysis - Preferred Process
Wisconsin Process and Results
North Carolina Process and Results
Iowa Process and Results
Comparison of States
Update on Michigan, New Hampshire, Georgia, and Nevada
Conclusions

3. Crash Analysis Process
Census of All Rural
Thru-STOP
Intersections
Determine Efficiency
of State’s Crash
Records System
Very Efficient
(i.e., MN & IA)
Separate
by facility
type.
Less Efficient
(i.e., WI, NC, & MI)
Sample of Rural
Intersections - State
Technical Liaison
Screens to No More
Than 75 Intersections
State DOT
Selection of
Test Intersection
4-Legged;
Two-Lane
Roadways
4-Legged;
Expressways
Identify
intersections
over the
critical crash
rate.
Detailed
review
of crash
conditions.
Top 3-6
Candidates
Candidate
Intersections,
Two-Lane
Candidate
Intersections,
Expressways
Identify intersections with high crash frequency, severity, and number of crossing path crashes.

4. Wisconsin Process Limitations of Wisconsin Crash System
Unable to automatically identify intersection locations
No ability to link traffic control and intersection geometry
State DOT Selected Corridor With Known Crash Problem
US 53 from Rice Lake to Superior (~ 70 miles)
Mainline volumes range from 4,700 to 11,000 vpd
74 intersections had at least one crash in 6.5 year period (Jan. 1, 1999 to June 30, 2004)
6 intersections were identified as candidates for deployment based on crash history

5. US 53 Study Corridor

6. Typical Candidate Intersection
Typical Median Design
(CTH B, Douglas County)
Typical Approach Design
(EB Approach at CTH V, Barron County)

7. Vertical and Horizontal Curves
Horizontal Curve at STH 77, Washburn County
Crest Vertical Curve to North of CTH V, Barron County
Horizontal Curve and Independent Vertical Alignment
South of CTH B, Douglas County

8. Unique Features Median Design at STH 77, Washburn County
Example Offset Right Turn Lane
(CTH E and US 63, Washburn County)

9. Wisconsin Crash Summary

10. Wisconsin Crash Summary

11. North Carolina Process
Limitations of North Carolina Crash System
Unable to automatically query intersection locations based on traffic control and intersection geometry - creates difficulties in computing an expected rate for subsets
State DOT Selected Intersections from HSIP (Highway Safety Improvement Program)
The intent of HSIP is to “identify locations that exceed minimum warranting criteria developed by safety engineers for particular crash types and patterns for further analysis and investigation”
HSIP criteria used were I-1 (minimum number of frontal impact crashes) and I-5 (chronic crash pattern)
Intersections were also thru-STOP, and the major roadway was a four-lane divided highway with a speed limit > 55 mph
59 of the top 300 HSIP intersections met the criteria, but only 12 had no safety improvement projects recently implemented

12. North Carolina Candidate Intersections
6) US 19 and SR 1390
5) US 74 and SR 1152
4) NC 87 and SR 1700
3) NC 87 and SR 1150
2) US 74 and SR 1574
1) US 74 and SR 2210 6 5 4 3 1 2

13. North Carolina Crash Summary

14. North Carolina Crash Summary

15. Iowa Process Census of all rural, expressway intersections
Selected the 20 intersections with the greatest difference between the actual crash severity index rate and the expected crash severity index rate
From list of 20, screened down to the 6 intersections with the most failure to yield crashes

16. Iowa Crash Summary

17. More Updates Michigan Georgia Nevada New Hampshire
Completed initial overview of crash data and working to identify a corridor OR a subset of intersections for analysis
Georgia
Discussions with Technical Liaison continuing
Nevada
Indicated preference to focus analysis on rural two-lane roadways
New Hampshire

18. State Comparison

19. Conclusions
Similar crash patterns have been found in Minnesota, Wisconsin, North Carolina, and Iowa
Similar crash rates, high severity, straight crossing path, farside location, gap related predominate
Many intersections have a high involvement of older and/or younger drivers
Weather and light conditions play minimal role in intersection safety problems