An On-Road Evaluation of Connected Motorcycle Crash Warning Interface
This study explored possible interface designs for motorcycle Crash Warning Systems (CWS) and evaluated their rider acceptance and effectiveness in a Connected Vehicle Technologies (CVT) context. Most previous motorcycle CWS studies were conducted in simulated environments where risk was well controlled. However, compared to other drivers, motorcycle riders are riding in a relatively exposed and dynamic environment where motorcycle noise, wind impacts, vibration, etc. are present, which increases the difficulties of reproducing a realistic riding environment in a simulator. This study was designed to evaluate a prototype motorcycle crash warning interface (CWI) and collect measures of user acceptance and input within realistic on-road riding scenarios in a connected vehicle environment.
Four prototype warning interface displays covering three warning mode alternatives (auditory, visual and haptic) were designed and developed for the motorcycles. The warnings were also designed to present two urgency levels (caution alert and warning alert).
The CWS was tested on-road with three connected vehicle safety applications that were selected according to the most crash types identified to have the highest impact for motorcycles:
- 1. Intersection Movement Assist (IMA)
2. Forward Collision Warning (FCW)
3. Lane Departure Warning (LCW).
The road test took place on the Virginia Smart Road, a 2.2-mile test track in Blacksburg, Virginia. Exercising the warning interface was done by manual control for each CV-based CWS application rather than using real-time algorithm calculations to ensure that experimental focus remained on the interface itself. A mixed-factorial experimental design was used in this study where the 39 licensed participants experienced all application scenarios (three levels – IMA, FCW, and LCW) with each CWI display (four levels – visor-mounted LED strips, in-helmet headset, haptic wristbands, and a combination of all (combo), including mirror-mounted LED strips) in a balanced order. Along with the CWI, two motion cameras (capturing rider torso and head, and forward roadway and hand(s) respectively) were mounted on the motorcycle’s handlebar and on a backpack carried by the riders. Rider acceptance was assessed by collecting subjective data through a set of questionnaires that allowed the participants to reflect on their experiences to provide measures such as desirability, usefulness, and system limitations.
- It was found that participants of sport, cruisers, and touring motorcycles had overwhelmingly positive views of potential CVT based motorcycle CWS, through its prototype CWI and applications. Although no significant difference in motorcycle type, cruiser and touring riders gave higher benefit ratings (averages are 6.23 and 6.37, on a scale of 7) to CWS applications than sport riders (average 5.31).
- A majority of participants (61.5%) thought warnings from the visor-mounted LED light strips were "obtrusive and distracting being in field of vision."
- While participants appreciated the new stimulation and location of the haptic wristband, many expressed concern about distinguishing between the haptic pulse and the motorcycle vibration.
- The majority of participants indicated that they did not notice the mirror-mounted LED strips at all.
- While the participants disliked the combo of all modalities for being "too much and distracting" they cited a combination of two displays as most ideal, with the auditory combined with haptic being the preferred pairing among the displays.
- In general, approximate times at which a response was observed in these scenarios were 2.58 seconds for the LCW scenario, 0.79 seconds for the FCW scenario and 0.74 seconds for the IMA scenario.