201850-uation of driving perance and user experience of different types of speedometer_W

1、Adjunct Proceedings of the 10th International ACM Conference on Automotive User Interfaces and Interactive Vehicular Applications (AutomotiveUI 18), September 2325, 2018, Toronto, Canada.Evaluation of Driving Performance and User Experience of Different Types of SpeedometerAbstractPreviously, the cl

2、assical analog speedometer was the preva- lent form of speed indication in cars. With the emergenceof new, freely programmable, instrument clusters, its now possible to use any form of visualization to display driving speed. In a driving simulator study with n=17 subjects, we examined the impact of

3、diverse speedometer variants on driving performance, gaze duration, and subjective ratings of user experience and workload. Initial results confirm di- verse effects. The conventional speedometer resulted in the shortest eyes off-road times, but was rated worst with re- spect to UX (hedonic quality)

4、. The digital speedometer vari- ant achieved polarizing results while the zoom speedome- ter performed very well in general. The bracket and linear versions of a speedometer were rated poor in most of the analyzed criteria compared to the alternatives.Paul KaufmannHuman-Computer Interaction GroupTec

5、hnische Hochschule Ingolstadt (THI), Germany paulkaufmannhotmail.deAndreas RienerHuman-Computer Interaction GroupTechnische Hochschule Ingolstadt (THI), Germany andreas.rienerthi.deAuthor KeywordsSpeedometer variants; Freely programmable instrument cluster; Driving performance; User experiencePermis

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8、owner/author(s). Publication rights licensed to ACM. AutomotiveUI 18 Adjunct, September 2325, 2018, Toronto, ON, Canada ACM 978-1-4503-5947-4/18/09./10.1145/3239092.3265951CCS Concepts Human-centered computing User studies;IntroductionSince its invention in 1902, the classical analog s

9、peedome- ter has been the prevalent form of speed indication in cars.Work-in-ProgressAutomotiveUI 18, Toronto, CanadaWhereas in the early days of cars the hand of the speedome- ter was mechanically connected to the engine, the technol- ogy available today allows for freely programmable instru- ment

10、clusters making it possible to use any form of visual- ization to display driving speed. It could be the right timeto rethink speedometers and use this potential to enhance driving performance as well as road safety and user expe- rience. The work of Kloeden 2 has pointed out that at a speed limit o

11、f 60km/h, the crash risk doubles with each 5km/h that a given car exceeds this speed limit. This il- lustrates how even small improvements in speed keeping could have significant effects on road safety, i. e., reduction of crash risk. In order to start a well-grounded comparison between different fo

12、rms of visualizations, we designed five speedometer variants based on different speed visualiza- tion forms that have been used in actual cars or show cars (see Figures 1 to 5). These designs were implemented as working prototypes using the Unity platform and tested in a driving simulator study.of t

13、he scale, and the font size scaling. After an experiment with static speedometers, tests in a driving simulator were conducted. Response time, gaze time, and subjective pref- erence of 16 subjects were recorded. The authors found that reaction time, response time, and gaze duration were longer for f

14、emale compared to male subjects. There was no objective difference in readability between round and half-round speedometers, but the half-round shape was more often preferred. Steps of 10mph resulted in better readability than steps of 20mph or 5mph. In addition, zoomspeedometers had a better readab

15、ility and received bettersubjective ratings than classic ones. In that work, different parameters of rotary speedometers were examined, but these are not compared with other alternatives, such as a linear or digital tachometer. Measuring driving performance would also allow for a better comparison o

16、f the variants.Figure 1: The classic speedometer was used as the baseline condition. It works with a radial rotary gauge and can be found in many production cars like, e. g., the BMW M4.Study Setup and MethodologyTo investigate qualitative and quantitative aspects of differ- ent speedometer variants

17、, we set up and conducted a driv- ing simulator study using a within-subjects design. 17 adult subjects (nine male, eight female) participated voluntarily in the experiment. All of them are in the possession of a driv- ing license for at least two years and some used visual aids to correct sight pro

18、blems. After filling in demographic data into an online questionnaire, the seating position was ad- justed and the subject had to put on the eye tracker, which was then calibrated on the subject. Next, the subject was walked through the driving simulator and was asked to per- form a trial run (at le

19、ast 2 rounds on the test track) without any speedometer or speed limits presented. After a suffi- cient number of introductory rounds (subjects felt safe in handling the driving simulator), the test started and each subject was asked to drive two rounds per speedometer type (ten rounds in total) on

20、a 2.4 km long oval track and adhere to the presented speed limits as close as possible.Related WorkIn 5, Szczerba et al. tested nine speedometers, which display the speed in relation to a given speed limit, in a between-subjects design desktop study. Subjects read the speed from static images of eac

21、h speedometer. The response times, response accuracy and the users subjec- tive usability ratings and preferences of the speedometer were recorded. Usual round or digital speedometers were preferred by test subjects. Rotary speedometers were gen- erally rated better than horizontal or vertical linea

22、r ones.All the speedometers were only tested as static prototypes on a desktop PC. The study thus lacks the relation to driv- ing itself, which is crucial for the evaluation of speedome- ters. Manna and colleagues 3 conducted another study examining the differences between different speedome- ters v

23、arying in shape (round, semicircular), the step sizeFigure 2: The zoom speedometer is based on the classic type but the size of its numbers scale in relation to the driving speed. It is used, for instance, in the 2017 BMW 3 and 4 series.Figure 3: The linear speedometer works by horizontally filling

24、a rectangle to indicate the driving speed. It was popular in the 1950s and 60s (e. g., in the 1959 Buick LeSabre) and is still today, especially in show cars.111Work-in-ProgressAutomotiveUI 18, Toronto, CanadaIn each round, six situations with different speed limits had to be solved. Each speedomete

25、r variant was presented to subjects in random order. Gaze direction was recorded with a binocular eye tracker (Pubil Labs) at 200Hz and visual resolution of 1280x720px. For each subject, the eye tracker was manually calibrated using calibration markers. In ad- dition, the seating position in front o

26、f the simulation wasindividually adjusted so that all subjects had the same sit- ting height (i. e., viewing angle) on the 50” simulator screen. The driving simulation was implemented in “Project Cars 2” connected to a “Logitech G90” gaming steering wheel. The simulation data was shared via an UDP i

27、nterface (10Hz) with the speedometer prototypes running in Unity. The speedometer variants indicated the cars speed on a 11.3” cluster display placed behind the steering wheel (Figure 6). Visual markers were stuck to the speedometer display to distinguish gaze direction (i. e., eyes-off-road time) b

28、etween driving simulation and speedometer. Speed limits were dis- played in the lower right corner of the cluster and gazes on those were later removed from the data. The speedometer prototypes also logged the cars speed for later comparison. After each drive, the subjects filled out an online quest

29、ion- naire about how difficult they found it to adhere to the speed limit shown and how much they liked the speedometer type they have just used. After the last drive, a final sum ques- tion had to be answered, followed by an unstructured inter- view. Finally, subjects were debriefed (total testing

30、time ca. 45 min).Questionnaire (UEQ-S) 4 was included in the question- naire. With UEQ-S, each speedometer type had to be rated with 8 questions (semantic differentials) on a 5 level Likert scale. The UEQ-S present results about the user experi- ence in two dimensions: the pragmatic dimension givesa

31、n assessment of the perspicuity and effectiveness of the system under test. In the hedonic dimension, its novelty and attractiveness are evaluated. Furthermore, three self- developed questions (7 level Likert scale from I agree com- pletely to I disagree completely) were included, targeting the perc

32、eived distraction (The speedometer I just used dis- tracted from driving), gaze duration (I could quickly read the speed from the just used speedometer), and precision of the just used speedometer (I could precisely read the speed from the just used speedometer). A sum question was asked post-test t

33、o query subjects about their personal perception of the different speedometer types by distribut- ing 100 points indicating subjective liking amongst the five variants.Figure 4: In the bracket speedometer, driving speed is indicated by filling abracket-shaped form. It is mainly used in show cars (e.

34、 g., the BMW concept 8).Results and DiscussionResults (see Table 1) show significant differences (Bon- ferroni corrected ANOVA, reported at p-values 0.05; details/full stats presented elsewhere 1) in speed in rela- tion to the speed limit (Speed; in km/h), eyes-off-road times (Gaze; in seconds), sub

35、jective distraction (Sub. D.; high score means low distraction), subjective precision (Sub. P.), as well as subjective gaze duration (Sub. G.D.) between speedometer types used. The analysis of the sum question shows a difference (not significant) between males (SUM. M.) and females (SUM. F.). The UE

36、Q-S results (values be- tween -3 and 3 are possible) were significantly different be- tween speedometer types in the pragmatic (UEQ-S PQ.) and hedonic (UEQ-S HQ.) dimensions. The NASA TLX showed significant differences only in the mental demand dimension (TLX MD), whereas the questions regarding per

37、-Figure 5: The digital speedometer displays the cars speed precisely as an numeric value and is more and more used in production cars, like in the 2017 Renault Captur.Questionnaire: The utilized questionnaire contained dif- ferent metrics. First, we included questions about mental demand, performanc

38、e, and frustration from the NASA TLX test 6, a standardized set of questions to measure per- ceived workload. (The other dimensions of TLX were disre- garded as they have no specific relation to the speedometer variants.) Second, the short version of the User Experience112Work-in-ProgressAutomotiveU

39、I 18, Toronto, Canadaformance and frustrations have not been answered signifi- cantly different. Additionally, female subjects deviated sig- nificantly more from the given speed limits than males did (Mf = 1.3; Mm = 0.93; in km/h).distraction ratings. This further led to the worst ratings of UEQ-S H

40、Q., as it was found to be less innovative than other speedometer types. The zoom speedometer was rated well in subjective distraction, subjective gaze duration, and UEQ-S PQ. Additionally, subjects deviated the least from the speed limit driving with this type of speedometer (dif- ference not signif

41、icant). It was, however, rated negativebut still better than the classic one in the HQ of the UEQ-S and can be seen as an interesting alternative. The linear speedometer had bad ratings in the UEQ-S HQ. as well as in the subjective and measured eyes-off-road times.Even though generally not preferred

42、, some subjects liked it the best and described it as relaxing and pleasant. Thebracket speedometer was rated worst in UEQ-S PQ., had the worst eyes off-road times, and highest cognitive load ratings in the NASA TLX, but was rated the best in UEQ- S HQ. This can be explained by its novel, unusual vi

43、su- alization (new to most users), which led to learning pro- cesses that resulted in cognitive load and hindered the speed reading, but also caused feelings of curiosity. Thedigital speedometer finally was rated the most precise and best in UEQ-S PQ. and generally stands out with high stan- dard de

44、viations in most parameters. Some subjects likedit very much, while others find it confusing and distracting. This can also be seen in the difference in its sum ratings of males and females.Table 1: Mean parameter values (M) for each speedometer type and their standard deviations (SD)ResultsFigure 6

45、: The setting as used in the study. The simulated drive is implemented in “Project Cars 2” connected to a “Logitech G90” steering wheel and displayed on a 50 TV screen. The cluster display is shown in front of the simulation screen and the visual markers in the corners are used to assess gaze behavi

46、or with a “Pupil Labs” eye tracker.ClassicZoomLinearBracketDigitalSpeed M Speed SD Gaze M Gaze SD Sub.D. M Sub.D. SD Sub.P. M Sub.P. SD Sub.G.D. M Sub.G.D SD SUM. F. M SUM. F. SD SUM. M. M SUM. M. SDUEQ-S PQ. MUEQ-S PQ. SD UEQ-S HQ. M UEQ-S HQ. SD TLX MD M TLX MD SD-0.161.290.440.152.761.444.181.594

47、.881.4113.757.9015.6711.031.191.41-1.930.9632.9420.70-0.190.760.540.242.821.294.001.415.181.4223.138.4315.8910.531.251.42-0.591.0634.1820.02-0.150.930.570.253.651.903.651.584.241.8223.1314.6218.8914.530.851.820.221.2534.1219.620.570.610.6053.651.584.121.9325.6317.829.566.21-0.181.931.340.

48、8252.0627.45-0.851.510.450.203.712.146.291.836.001.5414.3811.7840.0027.161.461.54-0.681.2646.4727.77Conclusion and Future WorkAlthough the conventional speedometers (types classic and digital) achieved good results in general, there is certainly room for improvements. In particular the zoom speedome- ter showed that new forms of visualizations could further enhance road safety and improve user experience and, thus, should be studied further and with larger sample si