TEMPORARY SPEED HUMP IMPACT EVALUATION CTRE Project 00-73 Sponsored by the Office of Traffic and Safety, Iowa Department of Transportation CTRE Center for Transportation Research and Education Final Report ● July 2002 The opinions, findings, and conclusions expressed in this publication are those of the authors and not necessarily those of the Iowa Department of Transportation. CTRE’s mission is to develop and implement innovative methods, materials, and technologies for improving transportation efficiency, safety, and reliability while improving the learning environment of students, faculty, and staff in transportation-related fields. TEMPORARY SPEED HUMP IMPACT EVALUATION CTRE Project 00-73 Principal Investigator Shauna Hallmark Assistant Professor of Civil and Construction Engineering, Iowa State University Transportation Engineer, Center for Transportation Research and Education Co-Principal Investigators Keith Knapp Former Assistant Professor of Civil and Construction Engineering, Iowa State University Former Manager of Traffic Engineering and Traffic Safety Programs, Center for Transportation Research and Education Gary Thomas Former Assistant Professor of Civil and Construction Engineering, Iowa State University Former Transportation Engineer, Center for Transportation Research and Education Research Assistant Dan Smith Authors: Dan Smith, Shauna Hallmark, Keith Knapp, and Gary Thomas Preparation of this report was financed in part through funds provided by the Iowa Department of Transportation through its research management agreement with the Center for Transportation Research and Education. Center for Transportation Research and Education Iowa State University 2901 South Loop Drive, Suite 3100 Ames, Iowa 50010-8632 Telephone: 515-294-8103 Fax: 515-294-0467 www.ctre.iastate.edu Final Report • July 2002 TABLE OF CONTENTS EXECUTIVE SUMMARY .........................................................................................................VII INTRODUCTION ...........................................................................................................................1 Problem Statement...............................................................................................................1 Research Objectives.............................................................................................................2 Organization of Report ........................................................................................................2 BACKGROUND .............................................................................................................................4 History of Traffic Calming ..................................................................................................4 Traffic Calming Devices......................................................................................................5 Volume Control Devices..........................................................................................5 Speed Control Devices.............................................................................................6 Temporary Traffic Calming.................................................................................................8 Temporary and Permanent Speed Hump/Table Design.......................................................8 Construction Materials and Practices.......................................................................8 Placement and Spacing ............................................................................................9 Geometric Design ..................................................................................................12 Signing and Marking..............................................................................................13 Speed Hump/Table Impacts...............................................................................................20 Impact on Emergency Response Vehicles.............................................................21 Speed Reduction ....................................................................................................21 Speed Hump/Table Public Opinion ...................................................................................30 DATA COLLECTION METHODOLOGY ..................................................................................32 Site Descriptions ................................................................................................................33 Roosevelt Drive—Atlantic, Iowa...........................................................................33 Redwood Drive—Atlantic, Iowa ...........................................................................34 Canal Shore Drive—Le Claire, Iowa.....................................................................36 Speed Hump/Table Installations........................................................................................37 Installation Process ................................................................................................39 Speed Hump/Table Site Locations.........................................................................39 Signing and Markings............................................................................................42 Data Collection Methodology............................................................................................44 Speed Data Collection............................................................................................46 Volume Data Collection ........................................................................................49 Resident Survey .................................................................................................................49 DATA ANALYSIS AND RESULTS............................................................................................50 Data Preparation.................................................................................................................50 Comparison of Mean Speeds .............................................................................................50 Comparison of Mean Speeds Before and While Speed Hump Was In Place........52 Comparison of Mean Speeds Before and While Speed Table Was In Place.........53 Comparison of Mean Speeds for Speed Hump Versus Speed Table.....................56 iii Comparison of Mean Speeds Before and After Speed Hump and Table Were Installed..................................................................................................................56 Reduction of Top Vehicle Speeds......................................................................................56 Changes in Speed Ranges ......................................................................................59 Changes in 85th Percentile Speed..........................................................................61 Optimum Spacing ..............................................................................................................64 Comparison of Speed Profiles ...............................................................................65 Determination of Optimum Spacing......................................................................70 Volume Reduction .............................................................................................................71 Description of Mann-Whitney Test .......................................................................75 Volume Results......................................................................................................75 Study Limitations...............................................................................................................76 RESIDENT SURVEY ANALYSIS AND RESULTS ..................................................................81 Question One: Familiarity..................................................................................................81 Question Two: Perceived Speed Change...........................................................................82 Question Three: Perceived Volume Change......................................................................83 Question Four: “What do you like most about the speed hump”?.....................................84 Question Five: “What do you like least about the speed hump”?......................................85 Question Six: Whether Speed Humps/Tables Should Be Installed ...................................86 Question Seven: Preferred Device.....................................................................................87 Question Eight: Additional Comments..............................................................................88 CONCLUSIONS AND RECOMMENDATIONS ........................................................................90 Average Vehicle Speeds ....................................................................................................90 Reduction of Top Vehicle Speeds......................................................................................91 Optimum Spacing ..............................................................................................................91 Speed Hump Versus Speed Table......................................................................................92 Short-Term Impact of Temporary Devices........................................................................93 Changes in Traffic Volumes ..............................................................................................93