1. Ali Kamyab Tom Maze Steve Gent Steve Schrock January 9, 2001 Center for Transportation Research and Education Iowa State University, Ames, Iowa Evaluation of Work Zone Speed Reduction Measures

2. Survey n 12 pages n Sent to:  50 State Transportation Agencies  14 Toll Road Authorities n 39 Returned (62%) Response Rate  37 State Transportation Agencies  2 Toll Road Authorities

3. Question 1 - Policy Description n Does your state have a policy on reducing or managing traffic speeds in work zones?  Policy: an automatic process governing the decision to reduce or manage… n 28 Agencies (72%) have a Policy n Varied Responses

4. Question 2 - Policy Procedure n How was your policy established? n Varied Responses n 22 Agencies, “Bottom-Up”  Engineering Level n 6 Agencies, “Top-Down”  Legislative Mandate or Directive

5. Question 3 - Scenarios n Drawings of Traffic Control Layouts n Questions:  Existing Non-Work Zone Speed Limit  Regulatory Work Zone Speed Limit  Advisory Work Zone Speed Limit

6. Speed Limit Signs RegulatoryAdvisory

7. Scenario 1 - Mobile Operation (2-lane/2-way) n Reg. Speed Reduction: 1 n Adv. Speed Reduction: 8  Generally 10 mhp n No Speed Reduction:20 n No Information: 9 n Not Applicable: 1

8. Scenario 2 - Mobile Operation (multilane-div) n Reg. Speed Reduction: 2 n Adv. Speed Reduction: 6  Generally 10-15 mhp n No Speed Reduction:26 n No Information: 5 n Not Applicable: 0

9. Scenario 3 - Lane Closure (w/o barrier) n Reg. Speed Reduction:26 n Generally 10 mhp n Adv. Speed Reduction: 4 n No Speed Reduction: 4 n No Information: 5 n Not Applicable: 0

10. Scenario 4 - Lane Closure (w/ barrier) n Reg. Speed Reduction:26 n Generally 10 mhp n Adv. Speed Reduction: 6 n No Speed Reduction: 2 n No Information: 5 n Not Applicable: 0

11. Scenario 5 - Lane Closure on Bridge n Reg. Speed Reduction:27 n Generally 10 mhp n Adv. Speed Reduction: 6 n No Speed Reduction: 0 n No Information: 6 n Not Applicable: 0

12. Scenario 6 - Lane Shift (multilane) n Reg. Speed Reduction:18 n Generally 10 mhp n Adv. Speed Reduction: 2 n No Speed Reduction:11 n No Information: 6 n Not Applicable: 2

13. Scenario 7 - Median Crossover (multilane) n Reg. Speed Reduction:30 n Generally 10 mhp n Adv. Speed Reduction: 0 n No Speed Reduction: 0 n No Information: 9 n Not Applicable: 0

14. Question 4 - System Effectiveness

15. Question 6 - Most Effective System n 25 Agencies Responded n Police Enforcement - 17 Agencies n Realistic Speed Limits - 3 Agencies

16. Concluding Remarks n Moving Work Zones: n Most Agencies – No Reg. Or Adv Speed Reduction n Lane Closure on Interstate: n Most Agencies – Reg. Speed Reduction n Generally 10 mph n Interstate Crossover/Head-to-Head Traffic n All Agencies – Reg. Speed Reduction n Police enforcement: n Most Effective Speed Reduction System