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This study aims at the development of a projection pattern that is capable of shortening the time required by a driver to perceive a pedestrian at night when a vehicle’s high beams are utilized. Our approach is based on the spatio-temporal frequency characteristics of human vision. Visual contrast sensitivity is dependent on spatiotemporal frequency, and maximum contrast sensitivity frequency varies depending on environmental luminance. Conventionally, there are several applications that utilize the spatio-temporal frequency characteristics of human vision. For example, the National Television System Committee (NTSC) television format takes into consideration low-sensitivity visual characteristics. In contrast, our approach utilizes high-sensitivity visual characteristics based on the assumption that the higher contrast sensitivity of spatio-temporal frequencies will correlate more effectively with shorter perception times.

We investigated a lighting method that supports pedestrian perception by vehicle drivers. This lighting method makes active use of visual characteristics such as the spatio-temporal frequency of contrast sensitivity. Using reasonable parameter values derived from preliminary experiments using a Campbell-Robson chart, we determined a suitable lighting pattern that improves the driver's pedestrian perception. In order to assess the influence of visual characteristics on a reaction-time-dependent task, such as pedestrian perception in nighttime, tests were performed in the target environment, the results of which validated the proposed method.

In the near future, the LED headlamps will be available in the market by improvement of the technique. There are some methods that can produce white light using LEDs. Probably, we think most generally method is using blue LED and yellow phosphor. But, spectral power distribution (SPD) of this type of white LED is much different from traditional white light that is produced by halogen or HID. This type of the white LED has poor spectral power in long wavelength region and much spectral power in short wavelength region. So, the white light by LED might have color-rendering problem. On the assumption that automotive head lamps with white LED and halogen, the human color perception and recognition under wide range of illuminance conditions from photopic to mesopic was measured, using categorical color naming method and elemental color scaling method. As the result of this measurement, stability of categorical color naming was lower under lower illuminance level with both light sources.

There is some concern that the lamps with clear outer-lenses, make it difficult in bright or sunny conditions to decide whether the stop lamp is on or not. In order to prevent the conspicuity problem for new product, simulation technology and a design guide for stop lamp with clear outer-lens is required. This report develops the relationship between conspicuity and luminance contrast by conducting the conspicuity experiment in both lit and unlit condition with the sample of LED light source and clear outer-lens. The precision of the optical simulation is also verified by comparing the experiment measurement and simulation result. This report demonstrates the new evaluation method from the result of experimental study and simulation analysis, as well as verifies its adequacy.

Headlamp aiming is one of the most important factors of lighting performance. In the U.S, visual/optically aimable headlamps must have a certain cut off vertical gradient for adjustment, and should conform to photometric requirements at its position. The manufacturer can choose a vertical cut off position either on the left side (VOL) or the right side (VOR) of the optical axis for particular headlamp system designs. However regulations aren't clearly written on headlamp aiming position on the vehicle. Even if the headlamp aiming is positioned correctly on the vehicle, the beam may cause discomforting glare to oncoming or ongoing road users, depending on the height of the lamp on the vehicle. This could also cause safety problems. The discomforting glare to oncoming drivers and the mirrors of ongoing traffic is compared between VOL and VOR of each headlamp height. This paper recommends optimum Lower-beam patterns at each headlamp height.

The present study was designed to investigate the customer preferences related to headlights, as measured by J.D. Power and Associates 1998 Initial Quality Study (IQS) - (“Headlights not aimed properly” question). We investigated beam patterns that ranged from high to low customer preference. As a result of our investigation, we have developed guidelines for desirable beam patterns for the U.S. market in terms of the sharpness of the cutoff, the foreground brightness, and the total flux value.

The present study was designed to investigate the advantage of a new headlamp system. This so-called smart headlamp system involves headlamps with variable beam patterns. We analytically investigated visibility for the driver and glare to other road users under several conditions including curves and straight roads. We conclude that the smart headlamp system provides overall benefits.

One of the primary reasons that FMVSS 111 currently requires flat rearview mirrors as original equipment on the driver's side of passenger cars is a concern that convex mirrors might reduce safety by causing drivers to overestimate the distances to following vehicles. Several previous studies of the effects of convex rearview mirrors have indicated that they do cause overestimations of distance, but of much lower magnitude than would be expected based on the mirrors' levels of image minification and the resulting visual angles experienced by drivers. Previous studies have investigated mirrors with radiuses of curvature up to 2000 mm. The present empirical study was designed to investigate the effects of mirrors with larger radiuses (up to 8900 mm). Such results are of interest because of the possible use of large radiuses in some aspheric mirror designs, and because of the information they provide about the basic mechanisms by which convex mirrors affect distance perception.

This study was designed to provide photometric information about current U.S. low-beam headlamps. The sample included 35 low-beam headlamps manufactured for use on the 23 best-selling passenger cars, light trucks, and vans for model year 1997. These 23 vehicles represent 45% of all vehicles sold in the U.S. The lamps were purchased directly from vehicle dealerships, and photometered in 0.5° steps from 45° left to 45° right, and from 5° down to 7° up. The photometric information for each lamp was weighted by 1997 sales figures for the corresponding vehicle. The results are presented both in tabular form for the 25th-percentile, the median (50th-percentile), and the 75th-percentile luminous intensities, as well as in graphical form (for the median luminous intensities, and median illuminance values reaching the road surface). The information is presented in aggregate form, as well as broken down by vehicle type and light source.

The goal of this study was to provide information about the frequency of installation and use of fog lamps. Two surveys were performed. In the first one, installation of fog lamps was estimated by a survey of parked vehicles in two iarge shopping centers. The second survey studied the usage of fog lamps during daytime and nighttime, under clear, rainy, or foggy conditions. In this survey, an observer in a moving vehicle noted the types of lamps that were energized on the fronts of oncoming vehicles, and whether fog lamps were installed at all. The main findings are: (1) The best estimate of the current frequency of installation of fog lamps in southeast Michigan is about 13%. (2) During daytime, the usage of fog lamps increased with deterioration in atmospheric conditions, with the usage reaching 50% of all installed fog lamps during moderate-to-heavy fog.