Truck drivers spend a long time sitting in small space, with variable sleeping hours and long stints driving through the night. This is amplified for truckers working during winter in Northern Europe, where daylight is in short supply. A research team at Daimler has looked into the effects of "artificial daylight" in truck cabins, finding light at the right wavelength can have a huge positive impact on drivers while they work.
Although we don't often think about it, light plays a big role in maintaining our mental wellbeing. Scientists have dedicated considerable time and effort to researching the effect of light on people who live in Northern Europe, where the dark winter months can cause poor moods, lower performance in their jobs and a general lack of motivation. Light therapy is one way to treat these symptoms, which are classed under the banner of seasonal affective disorder (SAD).
Having discovered that the shape of truck cabins limits the amount of natural daylight in the cabin, Daimler undertook a two-week study in Rovaniemi, Finland. Drivers were subjected to steady light while driving, an intense blast of light before/after driving, and light at maximum intensity while they reclined in their seats and napped. Testing took place over a two-week period, and drivers drove the same routes without the artificial light to form a baseline.
"Sunlight" came from a Mercedes Daylight+ module in the cabin, which emits light with a wavelength between 460 and 490 nanometers. Data was collected using electroencephalography (EEG), electrocardiography (ECG) and electrooculography (EOG) measurements. Drivers also gave saliva samples, their mental state was measured with standardized psychological tests, and driving performance was mapped using the on-board telematics system.
Not only did drivers report a significant improvement into their mood when using the new light, but on-board data showed drivers with more "daylight" in the cabin drove more economically than their sun-deprived selves. Drivers also said they found the space in the interior more pleasing with the special Daylight+ unit fitted.
"When designing the series of tests, we hadn't even considered that the [cabin] space might appear larger," says Siegfried Rothe, who led the research for Daimler. Beyond the initial findings, Rothe says it will take several months to sift through the test data and deliver full results.