Proceedings of the 22nd International Conference on Human-Computer Interaction (HCII 2020), Virtual (July 2020).

Operating two-wheeled vehicles in four-wheel-dominant environments presents unique challenges and hazards to riders, requiring additional rider attention and resulting in an increased inherent risk. Crashes involving motorcycles or bicycles with traffic vehicles (e.g. passenger cars, SUVs, pickup trucks, commercial trucks, buses) are disproportionately fatal compared to other types of motorcycle and bicycle accidents. Additionally, a significant proportion of non-traffic motorcycle and bicycle accidents, compared to car accidents, are attributed to the unique hazards riders face, such as potholes, inclement weather, uneven terrain, sand/gravel, construction zones, and even sharp turns and steep grades. As such, heightened risk requires heightened situational awareness and safety measures for riders on the road.

Unlike conventional smartphone-based GPS and handlebar-mounted alerting systems (e.g. Waze, SmartHalo), augmented reality (AR) heads up displays (HUDs) offer the ability to significantly enhance situational awareness while simultaneously supporting heads-up, eyes-out, hands-on riding. While HUDs maintain the ability to visually augment users’ field of view (FOV) with information at a relatively high level of specificity and detail, additional modalities, such as haptic and auditory displays, can also augment the riding experience while supporting heads-up, eyes-out, hands-on riding. Additionally, rather than assessing the detectability, usability, and viability of such alerting and communication modalities among the inherent dangers of live roadways, mixed reality (MR) and virtual reality (VR) offers the ability to replicate high fidelity, dynamic, and immersive riding environments that are also configurable and controllable, enabling us to test and validate augmented riding capabilities in realistic yet danger-free simulated environments.

Charles River Analytics has a significant XR portfolio (extended reality; collectively referring to AR, MR, and VR) with a growing body of XR work applied to transportation and specifically, to enhance the safety of two-wheeled riding (i.e. motorcycles and bicycles). This paper presents an overview of our work in this space with specific focus on the practical application of AR for real time hazard alerting for motorcycle and bicycle riders, and the use of VR for testing augmented alerting modalities in simulated riding environments.

Under a larger effort focused on emerging technologies for enhanced motorcycle rider safety, we designed, developed, and tested a system to support safe riding by alerting riders while en route to upcoming hazards, sourced and validated through crowdsourcing techniques, through visual, audio, and haptic AR reporting and alerting modalities. We have deployed this integrated, cloud-based system to various COTS AR devices, including the NUVIZ and Everysight Raptor HUDs, the SubPac M2X, Woojer, and bHaptics vibro-tactile wearables, and Bose Frames and in-helmet audio devices. We have conducted both informal and formal evaluations of these systems, including a controlled live-riding human subjects research study to assess and validate the usability and acceptability of HUD- and audio-based hazard alerting on the NUVIZ HUD, with promising (and generalizable) results. We discussed lessons learned regarding reporting (e.g., speech- vs. controller-based) and alerting (e.g., audio- vs. haptic- vs. visual-based) modalities, including multimodal and/or redundant options, as well as our recommendations for current deployment as well as future research and development.

Under a related effort focused on connectivity for enhanced bicycle rider safety, we designed, developed, and implemented an immersive mixed reality (MR) connected bicycle simulator for rapidly and representatively evaluating rider safety-augmenting technologies in a risk-free environment. This MR bicycle simulator allows participants to enter into an immersive virtual reality (VR) urban environment and control a virtual bicycle by riding on a stationary VR-ready exercise bike (to enhance realism) and then interacting with various virtual and real-world tracked objects and variables. Under a formal evaluation of rider-augmenting technologies within this effort, we conducted a study in which riders rode around the simulated VR city on a pre-planned bicycle path and were presented with common cycling hazards (e.g., potholes, cars cutting cyclists off at intersections, cars overtaking from behind with minimal clearance) at controlled random intervals. Riders were then presented with various alert modalities (e.g., visual, audio, haptic handlebars or wrist wearable, or some combination thereof) and their hazard response and response time were objectively measured (compared against a control condition without the added alerting). Initial results from this evaluation were also promising. We discussed the utility of augmented bicycle riding (i.e. alerting) as well as the opportunities a realistic mixed reality bike simulator, or similar concept, have for rapidly yet accurately evaluating practical applications of XR tech in near-real world deployment environments.

Finally, we discuss the ways in which these efforts can integrate for an end-to-end system to design, develop, test, validate, and deploy practical AR systems through the use of both AR, MR, and VR, as well as numerous emerging COTS devices. We conclude with our recommendations and predictions, based off our prior applied and empirical work presented throughout the paper, for the direction of XR systems in the context of practical transportation-based use cases.