WEATHER RESPONSIVE VARIABLE SPEED LIMIT SYSTEMS by Levi Austin Ewan A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering MONTANA STATE UNIVERSITY Bozeman, Montana April 2013 ©COPYRIGHT by Levi Austin Ewan 2013 All Rights Reserved ii APPROVAL of a thesis submitted by Levi Austin Ewan This thesis has been read by each member of the thesis committee and has been found to be satisfactory regarding content, English usage, format, citation, bibliographic style, and consistency and is ready for submission to The Graduate School. Dr. Patrick McGowen Approved for the Department of Civil Engineering Dr. Jerry Stephens Approved for The Graduate School Dr. Ronald W. Larsen iii STATEMENT OF PERMISSION TO USE In presenting this thesis in partial fulfillment of the requirements for a master’s degree at Montana State University, I agree that the Library shall make it available to borrowers under rules of the Library. If I have indicated my intention to copyright this thesis by including a copyright notice page, copying is allowable only for scholarly purposes, consistent with “fair use” as prescribed in the U.S. Copyright Law. Requests for permission for extended quotation from or reproduction of this thesis in whole or in parts may be granted only by the copyright holder. Levi Austin Ewan April 2013 iv ACKNOWLEDGEMENTS I would like to thank my graduate committee members, Dr. Patrick McGowen, Dr. Ahmed Al-Kaisy and Dr. David Veneziano, for their guidance and assistance offered throughout my entire master’s degree program. I wish to thank the Oregon Department of Transportation (ODOT) and the U.S. DOT University Transportation Center (UTC) program for funding of this research project. I would also wish to thank the ODOT project technical advisory committee (Ron Kroop, Dennis Mitchell, Galen McGill, Jason Shaddix, Joel McCarroll, Kathi McConnell, Luci Moore, Mike Barry, Mike Stinson, Sgt. Steve Schaer, and Nathaniel Price) for their input and assistance in this work. Thanks also go to Michelle Akin and Nick Johnson of the Western Transportation Institute and for their assistance in sensor testing and Dr. Ladean McKittrick of the Civil Engineering Department at Montana State University for assisting with the use of the subzero research facility. v TABLE OF CONTENTS 1. INTRODUCTION ........................................................................................................ 1 Problem Statement ........................................................................................................ 1 Proposed Solution ......................................................................................................... 2 Research Objectives ...................................................................................................... 2 Significance of Proposed Research ............................................................................... 3 Thesis Organization ...................................................................................................... 3 2. LITERATURE REVIEW ............................................................................................. 5 Weather Responsive VSL Systems............................................................................... 5 Arizona .................................................................................................................... 6 Australia .................................................................................................................. 6 Finland .................................................................................................................... 7 France ...................................................................................................................... 8 Germany .................................................................................................................. 9 The Netherlands ...................................................................................................... 9 New Jersey ............................................................................................................ 11 Sweden .................................................................................................................. 12 Utah ....................................................................................................................... 12 Washington State .................................................................................................. 13 Wyoming .............................................................................................................. 15 General Fog Systems ............................................................................................ 15 Other VSL Systems .................................................................................................... 17 Australia ................................................................................................................ 17 Colorado ................................................................................................................ 19 Delaware ............................................................................................................... 20 Maine .................................................................................................................... 20 Michigan ............................................................................................................... 21 Minnesota .............................................................................................................. 22 Missouri ................................................................................................................ 23 Nevada .................................................................................................................. 23 New Mexico .......................................................................................................... 23 Oregon .................................................................................................................. 24 Utah ....................................................................................................................... 24 Virginia ................................................................................................................. 25 Germany ................................................................................................................ 28 The Netherlands .................................................................................................... 29 Sweden .................................................................................................................. 29 United Kingdom ................................................................................................... 31 Other Weather Responsive Systems ........................................................................... 32 vi TABLE OF CONTENTS CONTINUED Wet Pavement Warning ........................................................................................ 32 Fog Advisories ...................................................................................................... 33 High Wind Warning .............................................................................................. 34 Icy Roads .............................................................................................................. 35 Flash Flood Warning ............................................................................................ 36 VSL Operational Issues .............................................................................................. 37 Weather Sensor Technology ....................................................................................... 40 In Pavement Sensors ............................................................................................. 40 Noninvasive Sensors ............................................................................................. 43 Weather Sensors in Use ........................................................................................ 47 Federal Guidance ........................................................................................................ 48 Conclusions ................................................................................................................. 51 3. STUDY SITE CHARACTERIZATION .................................................................... 54 Description of Study Site ............................................................................................ 54 Speed, Crash and Weather Data Analysis .................................................................. 55 Data Sources and Overview .................................................................................. 55 Speed Data Methods and Results.......................................................................... 56 Speed Analysis ...................................................................................................... 63 Crash Data Methods and Results .......................................................................... 64 Crash Analysis ...................................................................................................... 66 Conclusions ........................................................................................................... 66 4. WEATHER RESPONSIVE VSL: CONCEPT DEVELOPMENT ............................ 68 Purpose