Evaluating Effectiveness of Partitioning Complex Visual Displays on In-Vehicle Glance Behavior Momoha Takahashi 1,4, Ceyda D ü ndar 2,4, Yusuke Yamani 3,4, Donald L. Fisher 4 Smith College 1, Middle East Technical University 2, Old Dominion University 3, University of Massachusetts Amherst 4 Figure 2. The set-up of the display monitor and driving simulator. (The map display monitor is immediately to the right of the seat.) Method 8 young drivers performed the in-vehicle map task while navigating various virtual environments in a simulator. In the map task, they were asked to find the name of the target street within either partitioned or non-partitioned map displays. Their eye movements towards the visual monitor were recorded using a head-mounted eye tracker to measure the duration of off-road glances during the map task. This research was supported by a grant from the Liberty Mutual Research Institute for Safety to Donald L. Fisher, by Liberty Mutual-UMass Amherst Post-Doctoral Research Fellowship to Yusuke Yamani, and by a grant to Ohio State University from the Department of Transportation (Tier 1 UTC, PI Umit Ozguner). Background Driver distraction associated with in-vehicle technologies can compromise driver safety. Interaction with visually demanding displays can take drivers’ visual attention away from the forward roadway (Green, 2000). Off-road glances longer than 2 seconds increase the risk of near-crash and crash by at least two times (Klauer et al., 2006). Drivers’ tendency to glance away from the forward roadway is usually a function of the visual demand of the display. Map displays have been shown to generate very high frequencies of especially long glances away from the forward roadway. Motivation and Hypothesis Evaluation of novel information displays that help drivers limit the duration of especially long glances while scanning and reading a map. Hypotheses: Partitions help speed drivers’ processing and orienting in visual search within in-vehicle maps. Specifically, 1.Partitioning of visual displays reduces the frequency of especially long off-road glances during a map task throughout the entire glance sequence as a result of faster processing. 2.Participants should be able to use the partitioning information to orient themselves to where they were in the search when they return their glance inside the vehicle after having glanced outside the vehicle. 3.If drivers were given a repeated series of map tasks, then the percentage of especially long glance durations would increase across tasks, just as they increased within a single task (Yamani et al., 2014). Figure 1. Sample partitioned (left) and non-partitioned (right) maps used in the experiment. Figure 3. Probability of off-road glances longer than various thresholds for the early and late blocks in partitioned and non-partitioned conditions. Result Contrary to our expectation, the probability that drivers execute off-road glances longer than 2 seconds was smaller in the non-partitioned condition than in the partitioned condition, but the difference was not statistically significant. Visual inspection of Figure 3 indicates that the complimentary CDF for the late block is shifted to the right compared with the early block for the non-partitioned condition while that pattern was absent for the partition condition, suggesting that drivers executed more frequent especially long off-road glances across various threshold levels when displays are non-partitioned. To further explore the effects of partitioned displays, we analyzed the transition probabilities of eye movements during the map task: The mean transitional probability (0.30) did not reliably differ from 0.25 [one-sample t (6) = 1.27, p =.24]. Conclusion Contrary to our hypothesis, the partitioned displays did not produce any clear benefit over the non-partitioned displays on reduction of the probability of glances longer than 2 seconds. Drivers did not receive instructions regarding the use and meaning of the partitioning lines within different maps. The effects of the partitioned displays may arise only when drivers are explicitly told how to utilize the technology, but this awaits further experimentation. Due to the high visual demands associated with the map task, drivers may have devoted more cognitive resources towards the secondary task (the map task) over the primary task (the driving task). The difficulty of the map task might have produced the floor effects and overloaded drivers’ information-processing capacity. Analysis of transitional probabilities did not provide evidence that drivers utilized the partitioning. For the non-partitioned displays, drivers executed longer glances as the number of task interactions increased (at later trials in the experiment). Future study should examine if partitioning of complex displays can reduce off-road glance durations in various environments. References Green, P. (2000). Crashes induced by driver information systems and what can be done to reduce them. In Proceedings of the 2000 International Congress on Transportation Electronics. Society of Automotive Engineers: Warrendale, PA. Klauer, S.G., Dingus, T.A., Neale, V.L., Sudweeks, J.D. & Ramsey, D. J. (2006). The impact of driver inattention on near-crash/crash risk: An analysis using the 100- car naturalistic driving study data (No. HS ). Yamani, Y., Horrey, W.J., Liang Y., & Fisher, D.L. (2014). Sequential in-vehicle glance distributions: an alternative approach for analyzing glance data. Manuscript submitted for publication. (If drivers did not utilize the partitioning, a transitional probability becomes 0.25 because the quadrant of the next trial is chosen randomly and independent of the history of glance locations within a trial.)