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.