Impact of Cognitive Distractions on Drivers’ Hazard Anticipation Behavior in Complex Scenarios

Distraction is one of the main causes of traffic crashes. The effect of cell phones, a major contributor to cognitive distraction, on response time has tested in many simulator studies. Response time is not the only driving skill affected by cell phone conversations, however. Specifically, it is known that cell phone usage contributes to a reduction in hazard anticipation skills at intersections, and there are many other scenarios where cell phone conversations could have a detrimental effect. The objective of this study is to determine whether cognitive distractions associated with cell phone use affect hazard anticipation, not only at intersections but also in other scenarios which contain latent hazards. Twenty-four drivers navigated 18 scenarios on a driving simulator twice, with their eye movements continuously monitored. During one drive, participants performed a hands-free mock cell phone task while driving; on the other drive, they navigated through the virtual world without any additional tasks apart from the primary task of driving. The scenarios were classified into two types: intersection and non-intersection. Using a logistic regression model within the framework of generalized estimation equations, it was determined that the proportion of anticipatory glances toward potential hazards was reduced significantly for all scenarios when drivers were engaged in a mock cell phone task. Perhaps the most disturbing finding is that this was true both at work zones and at marked midblock crosswalks, scenarios which often endanger vulnerable road users. In summary, the study found a negative effect of cognitive distraction on latent hazard anticipation.

Impact of Cognitive Distractions on Drivers’ Anticipation Behavior in Vehicle-bicycle Conflict Situations

Overall, the rate of vehicle-bicycle collisions is continually increasing. In the United States alone, bicyclist fatalities contributed to 2.3 percent of all crash related fatalities in 2015. In most of these cases, crashes occur due to distracted drivers who are unable to correctly anticipate the bicyclists at the hazardous locations on the roadways such as, intersections and curves. The objective of the current study is to contribute to the divisive literature surrounding cell phone use while driving by specifically measuring, the effects of a secondary mock cell phone task on hazard anticipation performance across common vehicle-bicycle conflict situations. Two groups of 20 drivers each, navigated seven unique scenarios on a driving simulator while being monitored by an eye tracker. One group of participants performed a hands free mock cellphone task while driving, while the second group drove without any additional tasks outside of the primary task of driving. Analysis of the proportion of anticipatory glances using a logistic regression model revealed a significant main effect of the mock cellphone task at reducing the proportion of such glances made by the drivers towards potential bicyclist threats on the roadway.

Cellular Adhesion and Spreading of Endothelial Cells Monitored in Real Time Using the Quartz Crystal Microbalance

We have applied the Quartz Crystal Microbalance (QCM) technique to continuously record the processes of endothelial cell (EC) adhesion, spreading and cellular mass distribution changes during initial cell to surface contact and homeostatic attachment. ECs (50,000) were layered onto a set volume of media in the QCM device and simultaneously in a mock cell used for photomicroscopy. As cells were observed in the mock cell device to contact and attach to the surface over 45-55 min, we measured in the QCM device a continuous decrease in frequency and continuous increase in resistance, achieving a maximum at about one hr (1400 Ω frequency change and 1400 Ω motional resistance change). These frequency and resistance values stabilized over the next 24 hrs and were unchanged out to 72 hr by QCM measurement (to ∼700 Hz, ∼700 Ω), as the cells were observed to spread in the mock device. Both bovine aortic (BAE) and bovine capillary (BCE) endothelial cells were studied and found to exhibit similar behavior. These studies demonstrate that QCM can be used to detect continuous changes in cell mass and viscoelastic behavior.