Sustainable Transportation Energy Pathways (STEPS), Plug-In Hybrid & Electric Vehicle Research Center
Kurani, Kenneth S., Jonn Axsen, Nicolette Caperello, Jamie Davies, Peter Dempster, Marilyn Kempster, Kevin A. Nesbitt, Tai Stillwater (2010) Plug-in Hybrid Electric Vehicle (PHEV) Demonstration and Consumer Education, Outreach, and Market Research Program: Volumes I and II. Institute of Transportation Studies, University of California, Davis, Research Report UCD-ITS-RR-10-21
We deployed a mixed-method study to engage households in a project of fitting a PHEV into their day-to-day lives, completing PHEV design exercises, and open-ended interviewing to afford them the opportunity to tell their story about their encounter with this new technology. Plug-in conversions of hybrid vehicles were made available to (predominately new-car buying) households throughout the Sacramento region for four to six weeks each. The vehicles were instrumented to report travel and energy; households were interviewed and surveyed. Volume I of this report summarized the 34 households who participated between August 2008 and February 2009; Volume II incorporates an additional 33 households who participated between March 2009 and February 2010.
Results from all 67 households—all selected in part because they can recharge a vehicle at home—indicate that while they will recharge a PHEV about once per day on average, there was wide and systematic variation across households. Recharging less than once per day was not necessarily a sign of forgetfulness, lack of engagement, or resistance. Some of the households who did not recharge every day were among the most discerning about how their travel and recharging behaviors interact. The PHEV designs created by the 67 households emphasized increased high (gasoline) fuel economy rather than all-electric operation in charge-depleting mode—as did the designs of prior representative samples of new-car buyers (who had not driven PHEVs) in the U.S., California, and northern California.
Over households’ PHEV trials, narratives were written about their encounters with the PHEV-conversions. The primary themes to emerge from comparing these stories are: changing driving behavior, recharging habits and etiquette, confusion about PHEVs and how they work, evaluation frameworks including payback analyses and heuristic assessments of whether PHEVs “save money,” how to incorporate environmental (or more generally, pro-societal) costs and benefits into assessments, and the future. The last may concern both a household’s considering whether a PHEV is in their future and pondering whether PHEVs point toward the future of all cars.
The exploration of the narratives of two households’ use of PHEVs equipped with custom-designed real-time energy feedback (REF) instrumentation reveal initial themes that serve as hypotheses for exploration with subsequent households: 1) safety and distraction, 2) motivational situations, 3) confusion about, or misinterpretation of, the feedback, 4) desire for some feedback, and 5) relationship between self-described competitiveness and driving behavior. Additional narrative assessments and empirical measures of any differences in real-world, on-road energy intensity because of energy feedback information for a larger sample of households will be reported when that analysis is completed.
Tracing social interactions by the participants about the PHEVs reveals that complex translation of ideas and information about PHEVs occurred as the PHEV drivers use their trial period to reflexively explore lifestyle and identity possibilities of these new vehicles. We found that interpersonal interactions were among the most important influences on participating households’ assessments of PHEVs. The degree of influence was more likely to be greater if the interactions included communication about societal benefits, was with a person regarded as more expert, and was with a person who was socially close or far but not in the middle. The last may be an effect due to distinct types of networks, e.g., among the participating households.