Or at least that's what U.S. researchers say. Night drivers often lose their alertness because of fatigue, however blue lights, or blue light-emitting diodes, are believed to fool the brain into believing that it is morning, when in fact it is the middle of the night, thus resetting the body's natural clock. Recent studies have revealed that up to 30 percent of the fatal accidents involve large trucks, half of them taking place in the early hours because of fatigue.

"The concept of using light to boost alertness is well established [in other areas]. Translating that understanding into a practical application is the next challenge," says Mariana Figueiro, co-author in the study and Rensselaer Polytechnic Institute researcher. Figueiro envisions some kind of lighting source built into the cab of truck, which shines blue light; drivers would take "light showers" as long as 30 minutes, before continuing their trip.

Rensselaer Polytechnic Institute has been researching how light and blue light, in particular, affect alertness in sleep-deprived and non-sleep-deprived subjects, in the hope that accident rates in the afternoon could be reduced, with the application of light stimulators built in transportation vehicles. Figueiro argues that only after 45 minutes of basking in the blue light, drivers should feel a clear effect as brain activity in the 300-millisecond response is increased, thus enhancing alertness.

The experiments conducted at Rensselaer made use of a 470-nanometer light source, with a 40 lux light intensity. Alternatively, 450 and 470-nanometer wavelengths, with light intensities of 2.5, 5 and 7.5 lux, were tested in order to determine which is best at enhancing the reflexes of the driver. On the other hand, while blue LEDs may enhance the alertness of the driver, other wavelengths could help reduce the alertness of people, such as Alzheimer's disease patients, helping them sleep during the night.

Not surprisingly, some of the car manufacturers have already included the system in mass production to keep drivers more alert. A sensor system monitors various actions like eye movements or steering movement to determine whether or not the driver is alert; if not, the monitoring system automatically alerts the driver. Alerting one that he is fatigued is one thing, but keeping him from becoming drowsy is the main priority of the study.

Director of the sleep research center at Loughborough University, Jim Horne, says that it may even be possible to change the body's natural clock for short periods of time: "Shifting it by eight hours takes at least 10 days, and very few people are capable of doing that."