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This paper describes a study of visual responses to center high mounted stop lamps (CHMSLs) using a newly developed sweeping neon lamp. This study compares sweeping neon, incandescent, and light-emitting diode (LED) technologies. The incandescent CHMSL was a conventional after-market CHMSL brake light. The sweeping neon CHMSL used a novel controller whereby the luminous signal started at the center of the neon tube and grew in a “sweeping” motion outward toward the ends of the tube at an adjustable rate. The sweeping LED CHMSL had a segmented display simulating the sweeping characteristics of the neon CHMSL. Both the neon and LED CHMSLs had faster onset times than the incandescent CHMSL. Experimental subjects performed a tracking task cognitively similar to driving, and released a flip switch upon detecting the onset of the CHMSLs, which were mounted so as to be seen peripherally.

An experimental field investigation is described that compares off-axis (peripheral) visual performance between high-intensity discharge (HID) forward lighting and halogen systems. The goal of the investigation is to determine if the higher off-axis intensity levels combined with the spectral properties of HID lamps provide any benefits to visual performance over conventional tungsten halogen lamps. In this study three current production European headlamp systems, one HID and two halogen, are compared. These systems are used to illuminate a fixed scene. Subjects perform a visual tracking task, cognitively similar to driving, while simultaneously small targets located at various angles in the periphery are activated. Subjects release a switch upon detection and reaction times and missed signals are measured.

Recent studies have shown that high-intensity discharge (HID) headlamps provide visual benefits to the vehicle operator that may lead to greater nighttime driving safety.[1] This paper is an extension of that work to further examine the role of beam pattern. An experimental field investigation is described that explores the visual performance aspects of HID forward lighting systems meeting North American beam pattern standards. This study further explores and quantifies the overall benefits of HID systems by direct comparison to conventional halogen systems. It examines and compares two systems producing typical Society of Automotive Engineers (SAE) J1383 beam patterns. Subjects perform a visual tracking task, cognitively similar to driving, while seated in the driver's seat of a test vehicle. Simultaneously, small targets located at various angles in the periphery are activated, with subjects releasing a switch upon detection so that reaction times can be measured.

A research project has been completed to determine if commercially available blue coated lamps provide visual benefit for nighttime driving over standard tungsten halogen lamps. As an esthetic option, tungsten halogen lamps with an absorptive coating have been developed to mimic the appearance of HID lamps. The transmission of these coated lamp results in a continuous output spectrum, like standard tungsten halogen, but with a lower “yellow” content, giving an appearance similar to HID lamps. Aside from esthetic reasons for using blue coated lamps, there is also evidence that the spectral output may provide visual benefits over standard tungsten halogen lamps in nighttime driving. While driving at night, off-axis or peripheral vision is in the mesopic response range and the eye's sensitivity shifts towards shorter wavelengths or “blue” light.