User experience with electric vehicles while driving in a critical range situation - a qualitative approach - Nadine Rauh, Thomas Franke, Josef F. Krems

European conference on Human Centred Design for Intelligent Transport Systems 2014 Range Anxiety Range anxiety is a stressful experience of a present or anticipated range situation, where the range resources and personal resources available to effectively manage the situation (e.g., increase available range) are perceived to be insufficient. Rauh, N., Franke, T., and Krems, J.F. (2014).Understanding the impact of electric vehicle driving experience on range anxiety. Human Factors and Ergonomics. (in press) buyin g an EV  range satisfacti on  using EV for longer trips 

European conference on Human Centred Design for Intelligent Transport Systems 2014 Field Experiment  average available driving range 114 km when battery was fully charged  regenerative braking during deceleration  ECO PRO mode  digital remaining range display onboard navigation system  online screening questionnaire  68 participants (50 male and 18 female  average age 31 years  driver’s license since M = 12 years  M = 1300 km per month driving experience with a conventional car  M = km absolute driving experience with an EV  experiment took place in winter  94 km long round trip in a hilly rural area, mostly uphill during the first section  section of a German Autobahn in the last section  participants drove alone  round trip lead to a critical range situation  qualitative approach  structured interview immediately after they had completed the trip  participants were asked for different stress-inducing and stress buffering factors  framework: pre-study for a larger project: BMW ActiveE Leipzig – long- distance commuter field trial ( )

European conference on Human Centred Design for Intelligent Transport Systems 2014 Interview Questions  Q1 “What worried you during the test drive? Which situations led to increased stress?”  stress-inducing factors  Q2“What calmed you down? Which situations decreased your stress level?”  stress-reducing factors  Q3 “What would have helped you to be less stressed (e.g., which additional information before or while driving)?”  further strategies for reducing stress level

European conference on Human Centred Design for Intelligent Transport Systems 2014 Q1 – stress inducing factors "[...] at the beginning the range display - the remaining range - decreased relatively fast." (P12) "Well, every time when range fall below the remaining trip length." (P39)  relatively fast, clearly noticable decrease in range  small or even negative range safety buffers  uncertainty regarding energy consumption of the vehicle in general  uncertainty regarding consumption on the German Autobahn "Well, actually only in the first section, because at this time I could not estimate how much I will consume and how much I can regain." (P43)

European conference on Human Centred Design for Intelligent Transport Systems 2014 Q2 – stress-reducing factors (1) "Simply that you had enough remaining range to reach the destination." (P07)  sufficiency of range to reach the destination  deacrease in range safety buffers  higher certainty regarding consumption  user interface for tracking of the range safety buffer  precice, trustworthy feedback by the EV  familiarity with the route profile "It calmed me that I could always see: How much remaining range I have and how many kilometers I still have to drive?." (P03) "[…] that it goes downhill at the end and you can save some energy, that was relatively clear to me, because I know the route" (P09)

European conference on Human Centred Design for Intelligent Transport Systems 2014 Q2 – stress-reducing factors (2) "After finding the Eco-Pro mode - that calmed me, too." (P50) "Well, that you learn, as time passed, that your own driving style can contribute to a slower decrease of range." (P59) "And also to see, when you are driving downhill, and two or three kilometers are regained through regenerative breaking – you see at least, that it is somehow of use and it does something." (P16)  energy consumption assistance

European conference on Human Centred Design for Intelligent Transport Systems 2014 Q3 - additional stress-reducing ideas "What would help me is such a head-up-display, so that you don’t always have to look down […] So you can concentrate fully on the road and have all of the important information in the field of view." (P13) "That there is a display that shows how efficiently I drive. That means, I know that my battery, my engine, my complete energy consumption inside [the vehicle] worked optimally." (P18)  consumption calculated on the basis of the route profile ahead  feedback system regarding individual driving style  Head-up displays

European conference on Human Centred Design for Intelligent Transport Systems 2014 Summary and implications 8 Critical factors related to user experience in critical range situations System design recommendations Available range safety buffer displays, which allow for accurate tracking of the range safety buffer:  present relevant information simultaneously and close together  range safety buffer automatically computed by the system

European conference on Human Centred Design for Intelligent Transport Systems 2014 Summary and Implications 9 Uncertainty regarding EVs energy consumption due to:  individual factors (e.g., driving style)  environmental factors (e.g., route profile)  EV-related factors (e.g., different driving modes) Provide knowledge to reduce uncertainty:  general information through interactive manuals or trainings, e.g. about eco-driving about interpretation of display information  specific information while driving through comprehensive user interface, e.g. individualized feedback regarding the success of users’ efforts to reduce energy consumption recommendations for additional range enhancement strategies System design recommendations Critical factors related to user experience in critical range situations

European conference on Human Centred Design for Intelligent Transport Systems Thanks a lot for your attention! This study was funded by the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety.