1. AASHTO Subcommittee on Design Meeting June 10, 2004 NCHRP Project 3-69 Design of Construction Work Zones on High-Speed Highways Kevin M. Mahoney Penn State University

2. Project Objective Develop a comprehensive design-decision methodology for construction work zones on high-speed highways.

3. Panel James Kladianos, WY DOT Russel Lenz, TX DOT Herbert Roy, NYS DOT Robert Schlicht, FHWA John Smith, MS DOT Xiaoduan Sun, U of LA J. Richard Young, PBSJ Kenneth Opiela, FHWA Frank Lisle, TRB Charles Niessner, NCHRP Michael Christensen, Mn DOT (Retired) - Chair

4. Schedule Started: August 2003 First Interim Report: March 2004 Second Interim Report: August 2005 Completion: February 2006

5. What we learned: from literature 1. Crash rates: generally higher in work zones than outside (studies vary) 2. Dominant work zone crash type: rear-end (same dominant type as outside of work zones) 3. Dominant work zone crash location: activity area

6. What we learned: from literature Studies of design variables/decisions effect on safety: Work zone length: number of crashes increases with length Reduction of lane width: crash rates increase Diversion strategy: small effect on crash rates Freeway entrance ramp: effect of ramps not found; accel lane elimination or significant reduction may have negative effect

7. What we learned: from survey of state DOTs 1.Current practice: substance and variety 2. Priorities for research and guidance development under this project

8. State DOT Priorities

9. Bridge width Clear zone * Cross slope rollover Horizontal clearance Median slope Normal cross slope Normal shoulder slope Traveled way width * Shoulder type Shoulder width Sideslope Scope of design-decision methodology: Cross Section

10. Scope of design-decision methodology: Horizontal Alignment Compound curve ratio Radius of curve * Superelevation Superelevation transition

11. Scope of design-decision methodology: Vertical Alignment Critical length of grade Maximum grade Minimum grade Vertical curve

12. Scope of design-decision methodology: Other Barrier placement * Contractor traffic control plans * Design speed * Decision sight distance Stopping sight distance *

13. Development Methodology: Ideal Expected: Safety Mobility Performance Model Prevailing conditions Design variables

14. Development Methodology: Realistic

17. Candidate Focused Studies Statistical analysis of median crossover radii and paved roadway width Work zone speed profile model Performance of heavy trucks in work zones Roadside design and barrier placement guidance Influence of design features on driver performance Analyzing work zones using microsimulation

18. Sample ANN output for speed profile model

19. Possible format for roadside barrier placement design guidance

20. Challenges Performance measures Data Median crossover, radii and paved roadway width Crash locations while crossover in place

21. QUESTIONS?