Indexed on: 25 Jan '17Published on: 25 Jan '17Published in: Traffic injury prevention
We compared the differences in the braking response to vehicle collision between an active human emergency braking (Control condition) and a cruise control (CC) or an adaptive cruise control (ACC).In eleven male subjects, aged from 22 to 67 years, we measured the active emergency braking response during manual driving using the accelerator pedal (Control condition) or in condition mimicking a CC or ACC. In both conditions, we measured the brake reaction time (BRT), the delay to produce the peak braking force (PBD), the total emergency braking response (BRT + PBD), and the peak braking force (PBF). Electromyograms of leg and thigh muscles were recorded during braking. The Tonic Vibratory Response (TVR), Hoffman reflex (HR), and M-waves were recorded in leg muscles to explore the change in the sensorimotor control.No difference in PBF, TVR amplitude, HR latency, and Hmax/Mmax ratio were found between the Control and CC/ACC conditions. On the other hand, BRT and PBD were significantly lengthened in the CC/ACC condition (240 +/- 13 ms and 704 +/- 70 ms, respectively) compared to Control (183 +/- 7 ms and 568 +/- 36 ms, respectively). BRT increased with the age of participants while the driving experience shortened PBD and increased PBF.In male subjects, driving in a CC/ACC condition significantly delays the active emergency braking response to vehicle collision. This could result from higher amplitude of leg motion in the CC/ACC condition and/or by the age-related changes in motor control. Car and truck drivers must take account of the significant increase in the braking distance in a CC/ACC condition.