Watch Where You Step: Eye Tracking and Pedestrian Flow
A friend once used an analogy that traffic tends to move through streets as water moves down a stream, speeding up in certain areas, stopping in others, building at forks until the oncoming pressure pushes it in a pattern of various directions. Whether true or not, it’s an entertaining concept, and one that doesn’t seem too complex to study.
In fact, with progressing trends of sustainable development and urban planning, transport studies have become a topic of importance and interest within the architectural and engineering fields. One current trend, according to a study completed at University College London, is the development of predictive models of pedestrian movement. Human movement is a broad concept, encompassing migration, commuting, and smaller scale movements – like how people move through crowds, for instance. The researchers in England set out to observe spatial representation, human dynamics, and how both influence pedestrian behavior when combined.
In the study, researchers equipped participants with a head-mounted eye tracker and recorded their gaze patterns as they walked on a platform, maneuvering through obstacles at a normal speed. Two types of platform setting were used, one with two mannequins as obstacles and placed in the middle of the platform, and one without. The number of pedestrians varied on each platform, and during each session, participants were asked to walk at a natural speed from one end to the other until instructed to stop. Movements were recorded with infrared-laser range scanners every tenth of a second (in addition to manual observation by researchers).
One person from each session sported an iViewX Head Mounted Eye Tracking device which consisted of a lightweight helmet, an eye movement tracking camera, and a scene camera that captured field of view with gaze position monitored at about 25 frames per second. Fixations and saccades were observed as the pedestrian participants made their way along the platform, and the researchers made some fascinating observations.
Fixation on static obstacles along the platform was observed at the beginning of each walking session, and fixation on the platform surface itself was often observed during the walking session. Pedestrians also paid significant attention to a handrail running alongside the platform.
The researchers discovered that pedestrians pay much more attention to ground surfaces to detect immediate potential environmental hazards rather than fixating on more obtrusive and conspicuous obstacles. Most fixations were found to fall within a cone-shape area rather than a semicircle, as might be determined by a human’s natural field of view. And interestingly, the participants paid less attention to oncoming pedestrians than they did to static obstacles blocking the path.
As for whether or not they move like water, well, that’s another question for another story.