Zaijing Liu / UX Research
Previous Project
01 / Automated driving · Wearable devices · 2026

Comparing Smart Ring and Glove Wearable Interfaces for Takeover Requests in Automated Driving

A driving simulator experiment comparing ring, glove, and seat-back vibrotactile takeover-request interfaces, and the information types and request structures delivered through them.

Role
UX Researcher
Timeline
Oct 2025 – Jun 2026
Domain
Automated driving · Wearable devices
Driving simulator setup with three-screen highway scene and steering wheel
01

Overview

This project investigated how wearable vibrotactile takeover-request interfaces could support driver takeover performance in SAE Level 3 automated driving. We compared ring-, glove-, and seat-back vibration interfaces while also examining different information types and takeover-request structures in a driving simulator study.

02

Problem Statement

Level 3 automated driving requires drivers to quickly transition from non-driving activities back to manual control when a takeover request occurs. However, existing tactile warning interfaces can be sensitive to posture and device placement.

This study explored whether wearable vibrotactile devices, including rings and gloves, could provide a more effective way to support driver takeover.

03

Research Focus

The goal of the present study was to investigate the effects of device type, TOR structure, and information type on drivers' takeover performance in time-critical automated driving situations.

Wearable Device TypeHow do ring-, glove-, and seat-back vibrotactile interfaces differ in supporting driver takeover?
TOR StructureDoes a two-step takeover request with an auditory pre-warning support better takeover performance than a one-step request?
Information TypeHow do instructional and informative vibrotactile cues affect driver response during takeover?
04

Method

Experimental Design

The experiment used a 5 × 2 × 2 full factorial design to examine how wearable device type, takeover-request structure, and information type influenced takeover performance.

Wearable Device Type (5)One ring · two-ring · one glove · two-glove · seat-back (baseline)
TOR Structure (2)One-step TOR — vibrotactile cue 4 s before a potential collisionTwo-step TOR — 1 s auditory pre-warning, then the vibrotactile cue within the same 4 s budget
Information Type (2)Instructional — tells the driver which action to takeInformative — describes the hazard, leaving the driver to select the maneuver
Participants
40
licensed drivers

Forty licensed drivers (24 female, 16 male) were recruited from the SJSU SONA participant pool. Participants ranged from 18 to 64 years old (M = 24.57) and drove an average of 3.98 days per week.

24 / 16
Female / male
24.57
Average age (18–64)
3.98
Driving days per week
Simulator & Apparatus

Participants completed the study in a driving simulator using an SAE Level 3 automated driving scenario. The automated vehicle traveled in the middle lane of a three-lane highway while participants watched YouTube videos as a non-driving-related task. Vibrotactile takeover cues were delivered through five interface configurations: one ring, two rings, one glove, two gloves, and a seat-back vibration baseline.

The five vibrotactile configurations: one ring, two rings, one glove, two gloves, and a seat-back baseline
The five vibrotactile configurations — one ring, two rings, one glove, two gloves, and seat-back baseline
Scenario

Participants traveled in the middle lane of a three-lane highway under automated driving while watching YouTube videos as a non-driving-related task. When an obstacle appeared ahead, a takeover request prompted the driver to resume manual control and move into the open adjacent lane.

Procedure
01Consent & DemographicsParticipants reviewed the consent form and completed a short demographic questionnaire.
02TrainingParticipants completed approximately 15 minutes of training to become familiar with the simulator, takeover task, and wearable devices.
03Experimental SessionsParticipants completed 10 driving sessions covering five device conditions and two TOR structures.
04Automated Driving & NDRTDuring automated driving, participants watched YouTube videos as a non-driving-related task and responded to takeover requests when they occurred.
05Post-Session QuestionnairesAfter each session, participants completed subjective questionnaires assessing workload and device preference.
06Post-Experiment QuestionnaireAfter completing all sessions, participants provided feedback on their overall experience and device preferences.
Measures

We evaluated takeover performance and participants' subjective experience using both objective and subjective measures.

Metrics

Objective Measures

Takeover Time: Time required to respond to the takeover request. Shorter times indicate faster responses.

Information Processing Time: Time required to process the takeover information and select an action. Shorter times indicate faster information processing.

Maximum Resulting Acceleration: Maximum acceleration during the takeover maneuver. Lower values indicate smoother vehicle control.

Subjective Measures

Workload: Participants’ perceived workload during each condition. Higher scores indicate greater workload.

Acceptance: Participants’ perceived usefulness and satisfaction with the interface. Higher scores indicate greater acceptance.

05

Results & Discussion

Two-step takeover requests sped up responses but introduced trade-offs, while device configuration and information type shaped how useful the interface felt more than objective performance.

01
TOR Structure
Findings
  • Two-step TOR led to shorter takeover time and information-processing time.
  • But it also led to higher maximum resulting acceleration.
  • Two-step TOR received lower usefulness ratings.
  • Its workload effect depended on information type.
Discussion
  • Two-step TORs led to faster responses after the tactile cue.
  • The pre-warning may have helped drivers reorient earlier.
  • However, faster responses did not improve overall takeover quality.
  • Two-step TORs also showed a subjective trade-off, with lower usefulness and higher workload in the instructional condition.
02
Device Configuration
Findings
  • Device configuration did not affect objective performance.
  • Usefulness: two-glove > two-ring.
  • Satisfaction: two-glove > one-glove.
Discussion
  • All devices provided clear directional information after training.
  • Two-glove and two-ring showed higher usefulness ratings, which may reflect better spatial mapping of the tactile cues.
  • Glove devices may also have been more comfortable because the tactors fit better on the back of the hand.
03
Information Type
Findings
  • Information type did not affect objective performance.
  • Informative cues received higher usefulness ratings than instructional cues.
Discussion
  • Both cue types supported similar objective performance after training.
  • Informative cues received higher usefulness ratings, perhaps because they provided more context about the driving environment.
  • In the instructional condition, the pre-warning may have felt redundant and increased workload.
06

Limitations

Scenario limitationThe study used one trained lane-change scenario with a fixed 4-s lead time, so the results may not generalize to other urgency levels or more complex driving situations.
Participant limitationParticipants were recruited from one institution and were relatively young, which may limit generalizability to older drivers and broader populations.
Device limitationThe C2 tactors were relatively large compared with commercial finger-worn devices, which may have affected comfort and tactile perception.
07

References

Brandenburg, S., & Roche, F. (2020). Behavioral changes to repeated takeovers in automated driving: The drivers’ ability to transfer knowledge and the effects of takeover request process. Transportation Research Part F: Traffic Psychology and Behaviour, 73, 15–28. https://doi.org/10.1016/j.trf.2020.06.002

On-Road Automated Driving (ORAD) Committee. (2021). Taxonomy and Definitions for Terms Related to Driving Automation Systems for On-Road Motor Vehicles. SAE International. https://doi.org/10.4271/J3016_202104

Huang, G., & Pitts, B. J. (2022a). Takeover requests for automated driving: The effects of signal direction, lead time, and modality on takeover performance. Accident Analysis & Prevention, 165, 106534. https://doi.org/10.1016/j.aap.2021.106534

Petermeijer, S., Doubek, F., & De Winter, J. (2017). Driver response times to auditory, visual, and tactile take-over requests: A simulator study with 101 participants. 2017 IEEE International Conference on Systems, Man, and Cybernetics (SMC), 1505–1510. https://doi.org/10.1109/SMC.2017.8122827

Green, M. (2000). “How Long Does It Take to Stop?” Methodological Analysis of Driver Perception-Brake Times. Transportation Human Factors, 2(3), 195–216. https://doi.org/10.1207/STHF0203_1

Lindemann, P., Müller, N., & Rigolll, G. (2019). Exploring the Use of Augmented Reality Interfaces for Driver Assistance in Short-Notice Takeovers. 2019 IEEE Intelligent Vehicles Symposium (IV), 804–809. https://doi.org/10.1109/IVS.2019.8814237

Walch, M., Lange, K., Baumann, M., & Weber, M. (2015). Autonomous driving: Investigating the feasibility of car-driver handover assistance. Proceedings of the 7th International Conference on Automotive User Interfaces and Interactive Vehicular Applications, 11–18. https://doi.org/10.1145/2799250.2799268

Politis, I., Brewster, S., & Pollick, F. (2017). Using Multimodal Displays to Signify Critical Handovers of Control to Distracted Autonomous Car Drivers. International Journal of Mobile Human Computer Interaction, 9(3), 1–16. https://doi.org/10.4018/ijmhci.2017070101

Lo, W.-H., & Huang, G. (2025). Directional vibrotactile takeover requests on a wrist-worn device: Effects of age, pattern type, and urgency in automated driving. Accident Analysis & Prevention, 220, 108093. https://doi.org/10.1016/j.aap.2025.108093

Meng, F., & Spence, C. (2015). Tactile warning signals for in-vehicle systems. Accident Analysis & Prevention, 75, 333–346. https://doi.org/10.1016/j.aap.2014.12.013

Pescara, E., Stubenbord, A., Röddiger, T., Fang, L., & Beigl, M. (2021). Where Should I Look? Comparing Reference Frames for Spatial Tactile Cues. 2021 International Symposium on Wearable Computers, 68–72. https://doi.org/10.1145/3460421.3478822

Jumet, B., Zook, Z. A., Yousaf, A., Rajappan, A., Xu, D., Yap, T. F., Fino, N., Liu, Z., O’Malley, M. K., & Preston, D. J. (2023). Fluidically programmed wearable haptic textiles. Device, 1(3). https://doi.org/10.1016/j.device.2023.100059

Martinez, K. D., & Huang, G. (2022). In-Vehicle Human Machine Interface: Investigating the Effects of Tactile Displays on Information Presentation in Automated Vehicles. IEEE Access, 10, 94668–94676. https://doi.org/10.1109/ACCESS.2022.3205022

Zhang, W., Zeng, Y., Yang, Z., Kang, C., Wu, C., Shi, J., Ma, S., & Li, H. (2021). Optimal Time Intervals in Two-Stage Takeover Warning Systems With Insight Into the Drivers’ Neuroticism Personality. Frontiers in Psychology, 12, 601536. https://doi.org/10.3389/fpsyg.2021.601536

Ma, S., Zhang, W., Yang, Z., Kang, C., Wu, C., Chai, C., Shi, J., Zeng, Y., & Li, H. (2021). Take over Gradually in Conditional Automated Driving: The Effect of Two-stage Warning Systems on Situation Awareness, Driving Stress, Takeover Performance, and Acceptance. International Journal of Human–Computer Interaction, 37(4), 352–362. https://doi.org/10.1080/10447318.2020.1860514

Eriksson, A., & Stanton, N. A. (2017). Takeover Time in Highly Automated Vehicles: Noncritical Transitions to and From Manual Control. Human Factors: The Journal of the Human Factors and Ergonomics Society, 59(4), 689–705. https://doi.org/10.1177/0018720816685832

Cohen-Lazry, G., Katzman, N., Borowsky, A., & Oron-Gilad, T. (2019). Directional tactile alerts for take-over requests in highly-automated driving. Transportation Research Part F: Traffic Psychology and Behaviour, 65, 217–226. https://doi.org/10.1016/j.trf.2019.07.025

Proctor, R. W., & Vu, K.-P. L. (2006). Stimulus-Response Compatibility Principles: Data, Theory, and Application (0 ed.). CRC Press. https://doi.org/10.1201/9780203022795

Next Project — 02
Usability Testing for the Meetup Website