How Artificial Daylight in Truck Cabs Improves Mental State of Drivers

Working long stretches with no daylight can be tough no matter what the profession. But pulling endless evenings in a dark truck cab can leave even the toughest of personalities with a serious case of the long-haul blues.

So Daimler Trucks got to wondering: Could the company significantly improve the mood of truckers if there were a way to turn day into night?

The results of a two-week experiment answered that question with a resounding, “Yes!”

To test its theory, Daimler researchers created a “Daylight+” module that could be installed in the cab of a truck to mimic daylight. The trick, of course, was to create light that comes close to the level of daylight that has an actual effect on human biology, but that was not so bright that a driver can’t actually see out the windows. The team found an effective wavelength between 460 and 490 nanometers.

Then, a team led by Daimler research director Siegfried Rothe installed the Daylight+ modules in truck cabs and recruited eight drivers to spend two weeks testing the system. Rothe’s general mission at Daimler is to find ways to improve the quality of life and work for truck drivers, in the hopes that it could be more appealing to a wider range of recruits.

In this case, Rothe took his eight test subjects to Rovaniemi, a town in northern Finland that likes to call itself “the official home of Santa Claus.” For two weeks, the drivers experienced near-dearness for almost the entirety of each day. Rothe used the Daylinght+ modules to deliver additional light in three different ways:

A lower, steady dose while driving.

A blast of light before and after driving.

Doses of light during breaks.

During the two weeks, the truckers each spent one week with typical light, and a second week driving with the Daylight+ module. They were hooked up to machines to measure their vitals, including an electroencephalography (EEG), electrocardiography (ECG) and electrooculography (EOG). The researchers took saliva samples to measure melatonin levels. The were subjected to various reaction tests on computers. And finally, the company measure driving performance using the data recorded by its telematics system.

The initial results were clear, Daimler said. The drivers’ moods were better, they reported feeling the cabs seemed more pleasant and larger, and their driving was more efficient and economical.

Rothe now plans to take the results back to lab to analyze them further before making recommendations about how Daimler might either add lighting or make design changes to its cabs.

Related: Daimler Trucks Unveils Redesigned 2018 Freightliner Cascadia