Exposure to blue light can help the driver remain alert while driving at night; and this works almost as good as a cup of coffee, says a new study.

About a third of all motorway-related fatalities occur due to sleepiness. In a CDC survey conducted last year, about one out of every twenty people had admitted that they'd dozed off while driving at least once in a month.

Taking naps helps people stay alert, but it is a highly impractical solution to the problem of sleepy drivers. Another option is to drink coffee which takes time and as a result drivers can get late. Researchers say that an "embedded anti-sleepiness device" that emits blue light can help drivers stay awake while driving.

Blue light is known to increase alertness by stimulating specialized nerve cells present on the retina called the retinal ganglion cells. These cells are connected to the area of the brain that is involved with keeping us alert. Stimulating these cells inhibits the production of melatonin that lowers alertness.

The study involved 48 healthy male participants aged 20 to 50 years. Participants had to drive 400 kilometers or about 250 miles at night.

Each participant completed three night drives that were spaced out by at least a week. All of them got a 15 minute break halfway through the journey that began at 1am and ended at 5:15am.

During the drives, the participants were either exposed to continuous blue light, or were given two cups of coffee; one before departure and another during break. The coffee had 200mg of caffeine or was decaffeinated and represented a placebo.

Researchers tested participants' alertness by analyzing the number of times each of them had encroached on road markings (hard shoulder or center line).

Drivers who were on decaffeinated coffee accidently crossed the line about 26 times, while those on regular coffee crossed it 13 times. Drivers exposed to blue light were almost as good as drivers who drank coffee as they crossed the line about 15 times.

In the study, eight of the 48 participants were so dazzled by the blue light that they couldn't continue driving. Researchers say that using blue light while driving can keep drivers, comfortable to blue light, alert at night.

The study was conducted by Université Bordeaux Segalen, France, and their Swedish colleagues and is published in the journal PLOS ONE.