Mobility technologies are transforming our cities. How can we develop them to support safer user interactions?

Aim #1

Comparing driver and pedestrian street crossing decisions

Leveraging a simulated traffic intersection to evaluate an individual’s crossing decisions from both driver and pedestrian perspectives.

Motivation

Signalized traffic intersections are variable decision-making environments where safety is paramount. Safe decision outcomes require road users to consider the interaction of many environmental factors including their proximity to an intersection, the changing states of traffic lights, and whether they are walking or driving. Individuals often encounter traffic intersections as both drivers and pedestrians, so understanding how crossing decisions differ between perspectives can help support the development of targeted traffic policies for these road users.

In this experiment, each participant views a series of pre-recorded videos of the traffic intersection from first-person driver and pedestrian perspectives. Presenting both perspectives to the same participant sample allows us to characterize the differences in their decision outcomes as they assume the role of driver and pedestrian.

Aim #2

Effect of a powered ankle exoskeleton on street crossing decisions

A collaborative effort with MIT Lincoln Lab to explore how wearable robotics might impact naturalistic decision making.

Motivation

Powered exoskeletons are a technology that restores or augments the mobility of its users in medical, military, and industrial settings, and include embodiments that support the head, torso, arms, and legs. When developing exoskeletons, it is relevant to ensure appropriate fit to user’s bodies as it can affect performance and comfort. 

Consider the Dephy ExoBoot, a commercially available powered ankle exoskeleton that is worn on both legs and has been designed to reduce the metabolic cost of walking. Researchers have used the Dephy ExoBoot to characterize its effects on stability and balance, gait kinematics, and optimizing its assistance. Despite being incorporated into numerous prior studies, the effect of the Dephy ExoBoot on user decision making has not yet been investigated.

This study sought to measure the effect of (1) a powered ankle exoskeleton, (2) the distance from the intersection at which the traffic light turns yellow, and (3) the presence of an oncoming vehicle on pedestrian street crossing decisions, head direction, and perceived mental workload. Understanding the interaction between these factors can support the development of future exosystems that minimize the impairment of cognitive abilities needed for task completion.

Results

Data were collected for twenty participants as they walked through a simulated traffic intersection. Findings indicate there was no effect of the exoskeleton on crossing decisions; however, perceived effort, frustration, and performance worsened when the exoskeleton was worn.