Sleep Science · Foundations
The open window doesn’t wake you
Window down, music up. It is the first thing we do, and it works: we feel more awake. That is the problem. In a simulator, with the radio on, drivers who had slept five hours said they were less sleepy for most of the drive, with no significant difference in how often they drifted out of lane.
OnlineWhat everyone does
Open the window, put the fan on cold, turn the music up. Talk to someone, if anyone is with you. These are the habits of anyone who has driven sleepy, and they share one thing: they wake the senses. Do they wake the driver?
What was measured
In 1998, at Loughborough, sixteen young drivers who had slept five hours drove for two and a half hours in a simulator, on a monotonous road, in the afternoon. After half an hour they got cold air on the face, or a radio station of their choice, or nothing. Reyner & Horne 1998
With the radio they said they were less sleepy for most of the drive. But the difference in lane crossings was not significant, and neither was the difference in the electrical activity of the brain. The cold air did little, and not for long. Reyner & Horne 1998
In 2012, in Sweden, the test was repeated on a real motorway, by day and by night, with the window open or music on for ten minutes. The window, opened two centimetres, changed nothing. Music lowered sleepiness a little, both reported and measured by how long blinks lasted, and only while it played. Schwarz et al. 2012
Figure 1
What was measured
Why that is worse than useless
If these habits did nothing, they would be harmless. The trouble is where they act: on the sleepiness you feel, which is exactly what your decision should rest on.
In the simulator, that is what the radio did: it turned down the feeling, not the lapses. You feel ready to carry on just when you should be looking for a place to stop. Reyner & Horne 1998
Why you can trust the sleepiness you feel: Tired or sleepy? →
What they are really for
The authors of the 1998 study put it plainly: at best, temporary expedients, perhaps enough to find a suitable place to stop. That is what they are for. Window down and music up, to reach the next rest area. Reyner & Horne 1998
In short
The open window gets you to the next rest area. There you stop.
It changes how awake you feel more than how you drive, and the effect ends when you close it.
What works
Stopping. A little sleep. A coffee. In 2006, on a real motorway at night, most young drivers who had a coffee or a thirty-minute nap drove as they did by day. After a decaf, few did. Philip et al. 2006
People reacted very differently, though, and none of this replaces sleep. The only thing that replaces sleep is sleep. Philip et al. 2006
Figure 2
Who drove at night as they did by day
What we know, and what we don't yet
We know
- Cold air, an open window and music have no effect on sleepiness, or a small one that lasts only as long as they do.
- In the simulator, the radio lowered reported sleepiness with no significant difference in lane crossings.
- On a real road at night, after a coffee or a short nap, most young drivers drove almost as they did by day.
We don't know yet
- The studies are few and small: sixteen drivers in the simulator, sixteen on the road, twelve in the coffee study, nearly all young.
- Whether more air, colder air or other music would change the result. On the road the window was opened two centimetres, and we have found no real-road studies that answer this.
- Talking to whoever is travelling with you, one of the most common habits. None of these studies tested it.
Sources
- Reyner LA, Horne JA. Evaluation of "in-car" countermeasures to sleepiness: cold air and radio. Sleep 1998;21(1):46-50. DOI 10.1093/sleep/21.1.46 · simulator
- Schwarz JFA, Ingre M, Fors C, Anund A, Kecklund G, Taillard J, Philip P, Åkerstedt T. In-car countermeasures open window and music revisited on the real road: popular but hardly effective against driver sleepiness. Journal of Sleep Research 2012;21(5):595-599. DOI 10.1111/j.1365-2869.2012.01009.x · real road
- Philip P, Taillard J, Moore N, Delord S, Valtat C, Sagaspe P, Bioulac B. The effects of coffee and napping on nighttime highway driving: a randomized trial. Annals of Internal Medicine 2006;144(11):785-791. DOI 10.7326/0003-4819-144-11-200606060-00004 · real road
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