Do drivers understand cyclists' communication cues?

In the last decade, cyclist fatalities in traffic collisions have increased. Therefore, the current study aimed to identify which cues drivers use to make quick and accurate judgments of cyclists' intent and whether cell phone use affects prediction accuracy. Sixty drivers viewed video clips of a cyclist performing combinations of different cues (position on the road, head movement, arm signals) and reported the cyclist's intended action (turn left, turn right, stop, or go straight) as indicated by arm signals defined by U.S. transportation laws. Half of the participants completed a last letter task simulating a cell phone conversation. Drivers predicted cyclists' intentions with above-chance accuracy; however, only arm signals significantly influenced correct predictions (p < 0.001), whereas head movement and position on the road had no significant effect. Simulated phone conversations reduced prediction accuracy, highlighting the dangers of distracted driving. Eye tracking revealed that drivers first fixated on the cyclist's back before shifting attention to the signaling arm. Post-study questionnaire data showed that although all drivers correctly defined the straight-arm turn signals, less than a quarter understood the bent-arm right turn signal. Over three quarters correctly defined the stop/slowing signal, but half indicated they would use a halt-motion instead. These findings suggest that cyclists should use straight-arm signals and consider adapting the stop/slowing signal to better align with drivers' expectations. Using communication cues that match drivers' mental models may reduce confusion, improve situational awareness, and help prevent collisions-especially when driver attention is compromised.