Abstract: The present studies examined the feasibility and acute alerting effects of additional in-vehicle lighting within a passenger car. These factors were examined during morning driving (Study 1) and evening driving (Study 2). In a balanced within-subjects design, 37 participants drove a test car two times in the morning or in the evening. The test vehicle was equipped with either a daylight-supplementing interior lighting system or a placebo system, which participants were told would refresh the air. Both studies used identical protocols, and participants participated either in Study 1 (n = 18) or Study 2 (n = 19). In both studies, corneal illuminance levels were recorded while driving. Feasibility of the systems was assessed using subjective ratings. Efficacy outcomes were spindle rates in the alpha bandwidth of electroencephalogram recordings, performance on a psychomotor vigilance task and subjective sleepiness ratings. In both studies, daylight-supplementing significantly increased corneal illuminances while driving and did not cause any negative visual side-effects. Study 1 revealed lower spindle rates while driving under daylight-supplementing lighting, indicating that drivers had higher physiological alertness when exposed to additional light in the morning. This alerting effect of daylight-supplementing lighting, however, was not observed in Study 2. In both studies, performance on the psychomotor vigilance task as well as subjective sleepiness ratings did not significantly differ between the experimental conditions. The present studies provide novel evidence for the feasibility and positive impact of daylight-supplementing in-vehicle lighting systems on the physiological alertness of drivers under naturalistic driving conditions. Further studies are warranted to evaluate carry-over effects of increased alertness on road safety measures.

Abstract: With urbanization expanding into natural areas, it is increasingly important to understand how species subject to human-induced habitat alteration respond to novel opportunities and stressors. A pervasive consequence of urbanization is artificial light at night (ALAN), which previous studies have found introduces both costs and benefits for vertebrates. This understanding, however, primarily reflects findings from laboratory-controlled experiments or comparisons of wild populations in areas with long- standing differences in ALAN regimes. Here, we investigated the short-term costs and benefits for Anolis lizards during the period of initial exposure to ALAN using realistic light levels for urban areas (mean ± SD = 87.9 ± 36.7 lx at a distance of 3 m). As compared to controls, we hypothesized that adding ALAN would result in behavioral and physiological changes over the short term for brown anoles and their arthropod prey. In contrast to predictions, ALAN did not increase arthropod abundance or extend anole activity into the night. Structural habitat and sleep site use changed little in response to ALAN, which exposed about one-third of sleeping anoles in ALAN plots to light at night due to our manipulation. However, this direct light exposure resulted in lizards being more easily roused from sleep compared to lizards sleeping in the dark in control plots or in shadows in ALAN plots. The apparent inability of some anoles to adjust their sleep sites to avoid ALAN exposure may have contributed to their increased responsiveness at night and decreased locomotor endurance in the day. Our study suggests brown anoles can experi- ence higher short-term costs than benefits during initial exposure to ALAN.