HUMANIST 2014 – Vienna – 05.06.2014

Development and evaluation of a driver coaching function for electric vehiclesDr. Marcus SCHMITZVienna, 05.06.2014

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Introduction

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Eco-driving approaches

Feedback mode- Visual (e.g. screen, HUD)

- Haptic (e.g. active acceleration pedal)

- Acoustic- eACC

Feedback timing- Before trip (e.g. tips for efficient

driving)- During trip (e.g. information on

current consumption)- After trip (e.g. information on total

consumption, costs)

Implementation- Integrated

- Mobile device

Functionality- General feedback

- Context-sensitive/situation-adaptive feedback

Content of feedback- Recommendations for efficient

driving- Feedback on actual driving

efficiency - Presentation of efficient route

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• Integrated approach with visual icons via head-up display• Real-time feedback during trip• Situation specific advices -> possibility to change driving

behavior immediately• Possibility of advice free driving -> reducing workload

and distraction• Considering safety critical aspects of driving• Specific advices for electric vehicles

eFuture ”Driver coaching function”

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Real-time driver coaching

Coaching advices1. Acceleration behavior2. Legal speed limit3. Speed behavior when approaching curves4. Achieving new target speed5. Speed behavior when approaching downhill sections6. Car following

Optimal behavior Actual behavior

Evaluation

Surrounding traffic

Traffic signs/rulesTopography

Energy consumption

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Evaluation study

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• Research questions – Is there an significant impact of the specific real-time coaching on

energy consumption (in comparison to unspecific coaching or sole verbal instruction)?

– Does the specific real-time coaching change the driving behavior?

– How do drivers evaluate the acceptance of specific real-time coaching?

Evaluation study

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• Study design

Evaluation study

Experimental Condition Baseline Eco-drive

Specific real-time advices

BAS(no instruction)

COA(verbal instructions + specific real-time advices)

Consumption scale BAS(no instruction)

SKA(verbal instructions + consumption scale)

Verbal instruction BAS(no instruction)

VER(verbal instructions only)

HUMANIST 2014 – Vienna – 05.06.2014

Coaching approaches

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Coaching advices - COA Consumption scale - SKA Verbal instruction - VER

Omit hard accelerating

Do not exceed the current legal speed limit

Keep constant speed while negotiating a curve

Decelerate by means of the electric brakeTry to omit hydraulic braking by means of anticipatory drivingSail over hilltops / sail when driving downhill in order to gain speedKeep a sufficient distance to leading vehicles in order to omit velocity fluctuations

HUMANIST 2014 – Vienna – 05.06.2014

Simulator

• Simulator – WIVW Driving simulator

Electric vehicle model with combined pedal solution

Measurement of energy consumption, acceptance/usability, and driving behavior

– Specific advices and consumption scale via head-up display

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HUMANIST 2014 – Vienna – 05.06.2014

Track & sample

• Track– 15 km test track including several

changes of speed limit, sharp curves, in-/declines, car following, and intersections

• Sample– N = 30 (16 women, 14 men)– Age: m = 33 years (sd = 14 years)

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Results

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Results – Energy consumption

• Baseline: no difference between groups

• Each method reduced significantly energy consumption

• No difference regarding energy consumption between feedback conditions

F(2, 27) = 1.83, p = .180Energy consumption

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Results – Driving behaviour

F(2, 27) = 3.94, p = .032 F(2, 27) = 5.85, p = .008Velocity Positive acceleration

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Results – Driving behaviour

F(2, 27) = 2.86, p = .075 F(2, 27) = 2.46, p = .105Deceleration Sailing

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Results – Acceptance

• Drivers assessed specific online coaching to be helpful • Subjective improvement of driving style and efficiency • Advices were rated to be

– not frustrating – not disturbing – not distracting – quite motivating – understandable

• Drivers criticised velocity advice to be too restrictive • Need to increase accuracy of the recuperation advice as

participants sometimes reached the according velocity too early or too late.

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Conclusions

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• Real-time feedback is acceptable and seen as more effective than the verbal instructions

• No difference regarding energy consumption between feedback groups

• Feedback type has significant impact on driving style-> Recommendation for specific real-time feedback• Long-term usage studies have to show impact on familiar and

unfamiliar routes• Further studies have to show which advices can be replaced by

the active accelerator pedal workload reduction• Drivers ask for more information about saved energy/saved

miles

Conclusion

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Many thanks!Würzburger Institut für Verkehrswissenschaften GmbH (WIVW)Robert-Bosch-Str. 497209 VeitshöchheimTel.: +49-(0)931-78009-116Fax: +49-(0)931-78009150e-mail: info@wivw.de

Dr. Marcus SCHMITZDipl.-Psych. Monika JAGIELLOWICZDipl.-Ing. Michael HANIGCand.-Psych. Thomas HAMMER