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

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

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

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

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

Speed Limit Signs RegulatoryAdvisory

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

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

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

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

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

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

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

Question 4 - System Effectiveness

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

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