1. April 7, 2009 Presented by: Tom Welch State Transportation Safety Engineer Prepared with the Assistance of: Dr. Tom Maze & Joshua Hochstein – Iowa State University Iowa State University’s Center for Transportation Research and Education (CTRE) administers the following programs: Bridge Engineering Center Center for Portland Cement Concrete Pavement Technology Construction Management & Technology Iowa Local Technical Assistance Program Iowa Statewide Urban Design and Specifications Iowa Traffic Safety Data Service Midwest Transportation Consortium Partnership for Geotechnical Advancement Roadway Infrastructure Management Systems IA-330/US-65/IA-117 & IA-330/F-17 Jasper County Intersections Discussion of Design Alternatives

2. DEFINING THE PROBLEM With Traditional Expressway Intersection Design Typical Problem: Far-Side Right-Angle Collisions

3. Typical Far-Side Right- Angle Collision * Courtesy of University of Minnesota Intersection Surveillance System Test Bed at US-52 & CSAH-9, Goodhue County, MN DEFINING THE PROBLEM With Traditional Expressway Intersection Design 6:42 AM CDT

4. Locations: IA-330 at County Road F-17 & IA-330/US-65/IA-117 Jasper County F-17 US-65 IA-330 US-65 IA-330 IA-117

6. Fatalities: Major Injuries: Indianola, Iowa47Brian Cole Nevada, Iowa79Opal Kassel* Collins, Iowa16Craig Hudson Kamrar, Iowa73Dorothy Donahue Kamrar, Iowa78Walter Donahue IA-330 and Co Rd F-17 * Driver was former DOT Director

7. CRASH TYPES: IA-330 & F-17 Far-Side Right-Angle Crashes ARE a Problem! 73% of Right-Angle are “Far-Side” at IA-330 & F-17

8. CRASH SEVERITY: IA-330 & F-17 Maze et al., 2004 [page 79] More Fatal & Major Injury Crashes Occur at IA-330 & F-17 Than on Average

9. MINOR ROAD DRIVER AGE IN RIGHT-ANGLE CRASHES AT IA-330 & F-17 Elderly Drivers More Involved in these Collisions

10. Highway Crashes are Complex  Driver conditions and behavior  A contributing factor in 95 percent of crashes  Primary factor in 67 percent of crashes  Roadway design and environment  A contributing factor in 28 percent of crashes  Primary factor in 4 percent of crashes  Vehicle  A contributing factor in 8 percent of crashes  Primary factor in 4 percent of crashes

11. YOUNG & ELDERLY DRIVERS Vision and Cognition Challenges Peripheral Vision is important to making judgements about placement, speed, and gaps in moving traffic –Young drivers are still developing peripheral vision –Along with other vision changes, older drivers also begin to lose peripheral vision

12. The Teen Brain Is Still Under Construction Recent Scientific studies reveal that the teen brain is still under construction until about age 25. The Prefrontal Cortex is the last part to develop. It also controls: –risk-taking – judgment – impulse control – speed assessment – distance assessment – ability to handle distractions

13. Medical Factors - Aging Drivers Eye Lens The lens of the eye becomes cloudy and yellow with age, giving faulty information for driving decisions. Depth Perception With age, people lose depth perception and peripheral vision making it harder to judge distance and speed Needed Light A 50-year-old needs 5 times more light to read than a 20- year old. At 60 he’ll need 10 times more light

14. ALTERNATIVES:

15. SIGNALIZATION 1)Creates Expressway Traffic Delay 2)Not Expected by Expressway Drivers 3)Don’t Necessarily Improve Safety (Change Crash Types, Not Severity) 4)Signals at the bottom of a hill are not desirable

16. INCREASED ENFORCEMENT: “It is generally considered that fear of arrest and punishment causes drivers to conform better to traffic laws and regulations and thus reduces accidents. On the other hand, there is evidence to suggest that enforcement crusades have little lasting effect. For example, in several experiments vehicle speeds and driver behavior were recorded before and after an intensive enforcement effort. No significant changes were found either in speeds or in the number of law violations. Other studies have shown that many drivers ignore speed limit and speed zone signs that do not conform with their usual driving habits.” Dr. Clarkson H. Oglesby Stanford University

17. Jasper Co. Sherriff Department Comments

18. Failure To Yield Right-of-Way Crashes 2004 -2008 5-year average per/year Vehicle Type that got pulled in front of Average annual crashes reported This depicts crashes involving a causal driver who failed to yield the right-of-way to another vehicle at an intersection 8 ft 16ft 17 ft 18 ft 66 ft 149 Motorcycle 738 Van or mini-van 1224 Pickup, van, small bus 4742 Passenger car 815 Sport utility vehicle 269 Large Trucks

19. Cost Estimate: ≈ $7-10 Million Safety Effectiveness Estimate: ≈ 60 – 80% Diamond Interchange

20. Out-of-the-way travel distance depends on spacing of U-turns, but 1500 to 5000 feet extra travel can be expected for a J-Turn Intersection. However, because the movements involved are less complex, the total delay time for indirect left-turn & crossing maneuvers may be equivalent to that of direct maneuvers at a traditional at-grade intersection. THE J-TURN INTERSECTION

21. The J-Turn Intersection reduces the total number of intersection conflict points from 42 to 24, reduces the crossing conflicts from 24 to 4, and spreads out the conflict points over a larger area. THE J-TURN INTERSECTION

22. J-TURN INTERSECTION SIGNAGE EXAMPLE

23. J-TURN ALTERNATIVE (IA-330/F-17) Approximate Proposed U-Turn Spacing From Main Intersection: ≈ 900 feet≈ 1600 feet

24. J-Turn Intersection at IA-330 & F-17 could… Prevent 100% of the collisions which occurred there over the last 6 years. THE J-TURN INTERSECTION