user experience with electric vehicles while driving in a critical range situation - a qualitative...

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)

buying an EV

range satisfaction

using EV for longer trips


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 = 15.73 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 (2012-2015)


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


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)


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)


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


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


Summary and implications

9

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


Summary and Implications

10

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 2014 11

Thanks a lot for your attention!

This study was funded by the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety.

user experience with electric vehicles while driving in a critical range situation - a qualitative...

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