Evaluating Freeze and Real-Time Probing for Situation Awareness Measurement in the Pedestrian Environment

An effective situational awareness (SA) method provides an accurate measure to explain a person's ability to respond to environmental elements. This study compared the effectiveness of two SA methods, freeze and real-time probing, in pedestrian environments. A good SA measure was indicated by the high accuracy of the participants' answers to these probing queries and the shorter response time to the correct answer for real-time probing. The methods were evaluated based on their sensitivity, intrusiveness, and predictive validity. SA was measured under distraction and non-distraction scenarios using probes and a verbal protocol to measure performance related to participants' attention to high-value objects. The results revealed that neither freezing nor real-time probing was sufficiently sensitive to distinguish between the distractions. Moreover, freeze-probing was better at predicting pedestrian performance than real-time probing, suggesting better criterion validity. Real-time probing is more likely to cause intrusion into the measurement, leading to lower pedestrian performance. Both probes have advantages and disadvantages for measuring SA in static and repetitive pedestrian environments. This study provides guidance on selecting effective SA measurement methods based on domain requirements, offering critical insights for evaluating designs and policies for pedestrian environments to reduce accidents and improve the safety of transport systems.