Car vibrations may be making you sleepier

The video discusses the impact of driver fatigue on car crashes in Australia, highlighting that 20% of fatal crashes are attributed to this issue. It explores research suggesting that gentle vibrations from car seats can induce sleepiness. An RMIT University study tested this theory using a virtual driving simulator, exposing volunteers to low-frequency vibrations. Results showed that participants exhibited signs of drowsiness within 15 minutes, which became significant at 30 minutes, continuing until the end of the 60-minute test.

What were the signs of drowsiness observed in volunteers during the study?

At what point during the test did the participants show significant signs of sleepiness?