Research into the effects of additional light on the mental perception and performance of truck drivers has shown an improvement in their wellbeing and concentration.

At the start of 2017 a research team at Daimler AG investigated the effects of having additional light in the cab during the darkness of winter in Finland. Eight test drivers simulated the daily work routine of a trucker over a period of two weeks. One week was spent on the road in a Mercedes-Benz Actros TopFit truck without additional lighting (the reference truck), and the other in a truck with Daylight+.

This truck was fitted with three light applications which illuminate the cab with lighting similar to daylight: first of all a light alarm which simulates sunrise; secondly a light shower in which the driver can ‘fill up‘ with 30 minutes of artificial daylight before and after a trip; and thirdly Daylight+ as a supplement to daylight while driving. The study primarily focused on tolerance of the light, sleep quality, and the performance of the drivers.

The results have been studied and shown that the adaptive Daylight+ was able to treble the daily dose of light while driving. Together with the light showers before and after a trip, it was possible to increase the light dose received in the cab more than five-fold compared with a normal daily dose. With Daylight+, the brightness in the cab is continually adjusted to the outside conditions by means of a sensor. As a result, the daily light dose can be increased significantly without dazzling the driver.

Dr Michael Schrauf, an internationally renowned expert on measuring brain waves, recorded brain activity using an EEG to identify inattentiveness during periods of driving. While the drivers generally showed different levels of alertness, all of the test subjects were more alert with Daylight+ than in the reference truck without lighting. Translated into minutes, Daylight+ reduced the inattentive period of driving from 44 minutes to 18 on average. It was also noted that when the cab was illuminated with Daylight+ the inattentiveness of the drivers did not increase in the afternoon, showing it was possible to avoid the typical afternoon slump.

Psychological tests were also carried out on the drivers to determine reaction speed. The tests showed that with Daylight+, the reaction capacity remained constant and fewer incorrect reactions occurred when carrying out monotonous tasks.

Data was not only recorded while driving, but also at night, to examine sleep quality. The results showed that in the week when the drivers drove the Daylight+ truck, the proportion of deep sleep experienced was higher. More deep sleep means more relaxing sleep, which in turn can result in higher performance.

In addition to the objective data, which showed positive results, in the questionnaires drivers completed, they subjectively scored the cab illumination very positively in terms of maintaining fitness, a sense of wellbeing, and concentration. They reported they enjoyed an improved mood, felt less tired, and perceived the cab as more spacious.

The study indicated that a driver working in conditions ‘with light‘ performed better and remained more alert and fitter than in conditions ‘without light‘, showing that Daylight+ could represent a further step towards enhancing road safety.