The Transition to Alternative Fuel Vehicles (AFVs): an Analysis of Early Adopters of Natural Gas Vehicles and Implications for Refueling Infrastructure Location Methods by Scott Kelley A Dissertation Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Approved June 2015 by the Graduate Supervisory Committee: Michael Kuby, Chair Ram Pendyala Elizabeth Wentz ARIZONA STATE UNIVERSITY August 2015 ABSTRACT Alternative fuel vehicles (AFVs) have seen increased attention as a way to reduce reliance on petroleum for transportation, but adoption rates lag behind conventional vehicles. One crucial barrier to their proliferation is the lack of a convenient refueling infrastructure, and there is not a consensus on how to locate initial stations. Some approaches recommend placing stations near where early adopters live. An alternate group of methods places stations along busy travel routes that drivers from across the metropolitan area traverse each day. To assess which theoretical approach is most appropriate, drivers of compressed natural gas (CNG) vehicles in Southern California were surveyed at stations while they refueled. Through GIS analysis, results demonstrate that respondents refueled on the way between their origins and destinations ten times more often than they refueled near their home, when no station satisfied both criteria. Freeway interchanges, which carry high daily passing traffic volumes in metropolitan areas, can be appropriate locations for initial stations based on these results. Stations cannot actually be built directly at these interchange sites, so suitable locations on nearby street networks must be chosen. A network GIS method is developed to assess street network locations' ability to capture all traffic passing through 72 interchanges in greater Los Angeles, using deviation from a driver's shortest path as the metric to assess a candidate site's suitability. There is variation in the ability of these locations to capture passing traffic both within and across interchanges, but only 7% of sites near interchanges can conveniently capture all travel directions passing through the interchange, indicating that an ad hoc station location strategy is unlikely to succeed. Surveys were then conducted at CNG stations near freeway interchanges to assess how i drivers perceive and access refueling stations in these environments. Through comparative analysis of drivers' perceptions of stations, consideration of their choice sets, and the observed frequency of the use of a freeway to both access and leave these stations, results indicate that initial AFV stations near freeway interchanges can play an important role in regional AFV infrastructure. ii DEDICATION To my family and friends for their unwavering support throughout. iii ACKNOWLEDGMENTS This dissertation would not have been possible without the support and contributions of many. First, I would like to acknowledge the NSF Grant 1025313, "Spatial Refueling Patterns of Drivers of Alternative-Fuel and Conventional Vehicles" for the funding that allowed completion of Chapter 2. I also would like to thank Clean Energy Fuels and Trillium for permission to conduct interviews at their stations, which provided the empirical data for Chapters 2 and 4. I would like to acknowledge the key contributions of Joseph Schoenemann, who provided many hours of GIS support for Chapter 2; ASU undergraduate students Patrick Zweifel and Jeff Martinez, who conducted the first round of surveys; and Michael McLaen of the Institute of Social Science Research, for help with survey and sampling design. I would like to especially thank the Marcus family for the Mel Marcus Memorial Fellowship, which was granted in 2014. This award allowed me to travel to Los Angeles and conduct the fieldwork necessary to complete Chapter 4. Finally, I would like to thank my committee for their valuable guidance throughout my time in graduate school at ASU. Most importantly, I would like to express my gratitude to my advisor, Dr. Michael Kuby, for the opportunity to pursue this degree in the summer of 2011. This dissertation would not have been possible without his energy, collaboration, and passion for the advancement of alternative fuel vehicles. iv TABLE OF CONTENTS Page LIST OF TABLES ................................................................................................................ viii LIST OF FIGURES .................................................................................................................. x CHAPTER 1 INTRODUCTION ....................................................................................................... 1 1.1 Overview ............................................................................................................ 1 1.2 Overview of AFVs and Key Issues ................................................................... 2 1.3 Research Objectives .......................................................................................... 6 1.4 Significance...................................................................................................... 10 2 ON THE WAY OR AROUND THE CORNER? OBSERVED REFUELING CHOICES OF ALTERNATIVE FUEL DRIVERS IN SOUTHERN CALIFORNIA.......................................................................................................12 2.1 Introduction ...................................................................................................... 12 2.2 Data and Methods ............................................................................................ 18 2.2.1 Survey ........................................................................................................ 18 2.2.2 Deviations .................................................................................................. 22 2.2.3 Closest Facility vs. Least Deviation Analysis .......................................... 23 2.3 Results .............................................................................................................. 26 2.3.1 Analysis of Station Chosen ....................................................................... 27 2.3.2 Comparison of the Four Groups ................................................................ 32 2.3.3 Comparison of the Two Groups Faced with a Choice ............................. 34 2.3.4 Subjective vs. Objective Detours .............................................................. 35 v CHAPTER Page 2.4 Discussion ........................................................................................................ 36 2.5 Conclusion ....................................................................................................... 40 3 AFV REFUELING STATIONS AND THE COMPLEXITY OF FREEWAY INTERCHANGES: THE SCALE DEPENDENCY OF REGIONAL HIGHWAYS ON LOCAL STREET NETOWRKS..............................................43 3.1 Introduction ...................................................................................................... 43 3.2 Data and Methods ............................................................................................ 51 3.2.1 Interchange Metrics and Candidate Nodes ............................................... 51 3.2.2 Freeway Traffic Capture Algorithm ......................................................... 52 3.2.3 Traffic Flow ............................................................................................... 57 3.2.4 Statistics and Topological Analysis .......................................................... 58 3.3 Results .............................................................................................................. 59 3.3.1 Interchange Physical Characteristics ........................................................ 60 3.3.2 Candidate Node FTCA Scores .................................................................. 61 3.3.3 FTCA scores and Distances from Interchange Center ............................. 63 3.3.4 Interchange-level FTCA Scores ................................................................ 67 3.3.5 Differences in Interchange Characteristics ............................................... 69 3.4 Sensitivity Analysis ......................................................................................... 71 3.5 Discussion ........................................................................................................ 73 3.6 Conclusion ....................................................................................................... 75 vi CHAPTER Page 4 FREEWAYS, TRIP TYPES, AND CHOICE SETS: OBSERVED AFV DRIVING AND REFUELING BEHAVIOR AT COMPRESSED NATURAL GAS (CNG) STATIONS NEAR FREEWAY INTERCHANGES......................79 4.1 Introduction ...................................................................................................... 79 4.2 Data and Methods ............................................................................................ 84 4.3 Results .............................................................................................................. 89 4.3.1 Choice Sets ................................................................................................ 93 4.3.2 Comparison to Freeway Traffic Capture Algorithm ................................ 97 4.3.3 Refueling Trip Types ............................................................................... 101 4.4 Discussion ...................................................................................................... 105 4.5 Conclusion ..................................................................................................... 109 5 CONCLUSION ..................................................................................................... 113 5.1 Review ........................................................................................................... 113 5.2 The Roles of Consumers and Fleets .............................................................. 116 5.3 Policy Recommendations and Strategies ...................................................... 118 5.4 Methodological Considerations..................................................................... 120 5.5 Future Considerations .................................................................................... 122 REFERENCES.................................................................................................................... 125 APPENDIX A CONSUMER CNG REFEULING SURVEY ...................................................... 131 B ALL SOUTHERN CALIFORNIA INTERCHANGE METRICS ...................... 135 C CNG INTERCHANGE REFUELING SURVEY ................................................. 139 vii LIST OF TABLES Table Page 2.1 Deviation, Closest Facility, And Least Deviation Analysis Results ...................... 27 2.2 Categorization Of Refueling Station Selection Of All CNG Drivers Surveyed… 28 2.3 Incorporation Of Marginal Cases Into The Absolute 2x2 Classification, By Rank Of Stations……………………………………………………………………… 29 2.4 Incorporation Of Marginal Cases Into The Absolute 2x2 Classification, By Time Difference Between Stations................................................................................... 33 2.5 Primary Reason For Choosing Refueling Station................................................... 34 2.6 Difference Of Means Results For Choice Groups................................................... 35 3.1 Statistical Comparison Of Freeway Interchanges: 3-way Vs. 4-way.... ................. 60 3.2 Distribution Of A = 1.0 Nodes Against Distribution Of All Nodes And Exit k Nodes........................................................................................................................65 3.3 Interchange Configuration Sub-types And FTCA Metrics... .................................. 66 3.4 Interchange Factor Comparison For Those That Have At Least One Candidate Node Where A =1.0 And Those That Do Not... .................................................... 70 k 4.1 Mean Values Of Stated Preference Likert Scale Questions, By Station..... ........... 91 4.2 Trip Characteristics By Station (% or Mean Value).............................................. 92 4.3 Choice Set Characteristics Of Drivers, By Station................................................. 95 4.4 Comparison Of Theoretical Refueling Traffic Capture Passing Through Interchange And Observed Data From CNG Refueling Survey............................ 99 4.5 Characteristics Of CNG Drivers Who Refueled Based on Freeway Use Category..................................................................................................................103 viii Table Page 4.6 Logistic Regression Model, Predictors For Refueling Trips Doubly Freeway- Anchored Against Those That Were Not.... .......................................................... 104 ix