The Effect of Hands-Free Cell Phone Conversation on Psychomotor Performance Required for Safe Driving: A Quasi-Experimental Study

Background: Hands-free cell phone conversation (HFCC) while driving is a common practice among drivers. Several studies have revealed that HFCC, while driving, is no safer than hand-held cell phone conversations (HHCC). This study was conducted to explore the influence of HFCC on the psychomotor performance of drivers. Methods: In this quasi-experimental study, the participants were randomly allocated into 2 groups. Participants in group1 passed the traffic psychological battery of the Vienna test system (VTS) once without being engaged in any phone conversation and again while making a HFCC. The order of testing in the 2nd group was reversed. All participants shifted their group and passed the tests in a reverse order after 7 to 10 days. The tests included peripheral perception, perceptual speed, general intelligence, visuomotor coordination, and time anticipation. The mixed model analysis was used to assess the association of HFCC with every test. Results: A total of 24 students, with a mean age of 27.1 ± 5.3 years, were included in the study. HFCC had a significant negative influence on the overall mean duration (P value = 0.015), overall percent error duration (P value 0.001) in visuomotor coordination median deviation time (P value = 0.007) in time anticipation, divided attention in peripheral perception test (P value = 0.053), and general intelligence (P value = 0.005). However, perceptual speed and field of vision did not reveal any significant association. Conclusions: These findings provided further evidence of the adverse effects of HFCC during driving. Even though drivers can per- ceive an obstacle while talking on a hands-free cell phone, they are highly likely to react incorrectly due to impairment of visuomotor coordination, time anticipation, divided attention, and fluid intelligence.