"Light therapy" tests conducted on a team of truck drivers in Finland have found that filling a truck cabin with artificial daylight can lift mood, alertness and perception and even boost a subject's ability to drive economically.

At this time of year, much of the motoring industry packs its bags and heads to the Arctic Circle to carry out winter driving tests for their latest models.

However, alongside the supercars performing snow-plough turns, and family hatchbacks starting first time in sub-zero conditions, was a team of eight Daimler test drivers, a fleet of trucks and a group of researchers led by Siegfried Rothe, who wanted to take advantage of Finland's zero daylight conditions in order to better understand how daylight can improve the task of navigating a rig.

The volunteer drivers each undertook two weeks of driving duty, one in a standard truck and a further week while driving a truck with a Daylight+ module fitted that provided additional daylight -- ie with a wavelength of between 460 and 490 nanometers -- within the cab during driving and breaks.

Subjects wore physiological measurement devices including EEGs and on the daylight week were exposed to steady streams of daylight during driving, intense light showers before and after driving and also daylight during power-napping in the cabin.

Rothe has spent years conducting experiments at the sleep lab at the University of Regensburg trying to quantify light's effects on the human body and his decision to take his tests on the road was inspired in part by the realization that the average truck cab design actually prevents daylight reaching the driver.

The amount of data collected will take several months to analyze properly. "Only then we will be able to make a recommendation as to whether the test findings should advisably lead to changes in the design of cab lighting," said Rothe.

However, initial findings suggest that drivers feel "better" when driving under the influence of improved daylight; that when there's more daylight in the cab, drivers drive more economically; and that the cockpit itself feels larger and more comfortable when the Daylight+ is in use.

"When designing the series of tests, we hadn't even considered that the space might appear larger," said Rothe.