Mechanical activation and EEG data from 22 participantsover ten brake light sets was analysed statistically. Timing results indicate that versions of brakelights containing incandescent bulbs were slower than all the eight LED lights (and this result was statistically significant). It is known that bulbs taken longer to light up (for example, there is usually no discernible light output until up to about 50 ms, after power is applied) but the cognitive reaction time delay was about 170 ms when comparing a bulb and its LED equivalent, which shows that LEDs have the ability to evoke brain responses quicker. Within LED, there were differences statistically as reported in the final report.
Comparing the age of participants, it did not show any difference, but driving experience mattered. We have used the unique timing analysis to identify the cognitive response after seeing the brake light and lifting the foot from the accelerator which would assist in understanding the influence of cognitive action component of raising the accelerator pedal after seeing the brake light. This analysis showed that at the slow end of the reaction time, inexperienced participants are especially slow.
EEG analysis based on the P3 component shows statistical differences in latencies from different brake lights. The bulbs were statistically slower than LED. Within LED lights though, EEG analysis does not show much difference. This might be due to noise present in the signal and implementing advanced noise reduction methods may reveal differences.
Please refer to the two published papers for full details of the results.
