Attentiveness in urban spaces: The rhythm of the street

Driver vigilance research focuses on the safety impacts of maintaining sustained attention in underload conditions when automatic responses are adequate to the task and responses are sparse. However, urban environments have frequent risks that appear chaotically and require high levels of engagement—a very different vigilance task. Although drivers perceive a wide range of task demands as manageable, their movement patterns hint at more active engagement as they approach overload. This condition we are calling “Attentiveness,” to distinguish it from the classic exploration of vigilance in underload conditions. To understand how the built environment impacts driving automaticity and vigilance, data from the SHRP2 Naturalistic Driving Study (NDS) was used to evaluate driving patterns within urban multimodal street sections. Data for acceleration, jerk, lane position, and speed were tabulated for ten, 5-second epochs at 200 multimodal locations and compared to the behavior for the entire length of the drive. The built environment variables that demonstrated a strong correlation and impact size for a change in driver behavior included doorway density, block length, Walkscore, corridor aspect ratio (height over width), and terminated vistas. The commonality for these variables is that each one impacts the rate that novel stimuli arrive as drivers progress sequentially along their path. Acceleration, jerk, and lane position appear to be related to the rhythm of interruptions that occur along the length of the roadway.