Abstract:
A variable lighting system (“VLS”) for optimizing object visibility at night by setting a base level of lighting, adding a variable light to that base level of lighting, and a synchronizing the timing and sequence of the base level of lighting and the variable lighting. The VLS varies the illumination by intensity, color, direction, or a combination thereof and optionally includes a detector for detecting motion, noise, and other occurrences. The VLS can be implemented as a fixed lighting source, a movable lighting source, or a vehicle mounted lighting source. The VLS improves visibility at night for viewers or motorists thereby reducing accidents and damage costs, saves energy, and improves the environment and enhances quality of life by reducing light pollution and light trespass.

Description:
RELATED APPLICATION INFORMATION 
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 11/179,956, filed Jul. 12, 2005, the content of which is incorporated by reference herein as if set forth herein in full. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    This invention generally relates to lighting systems. Particularly, the invention relates to lighting systems for optimizing night visibility. 
         [0004]    2. Description of Related Art 
         [0005]    Night visibility is a well known concern of many individuals and is particularly a safety concern for night driving. As a result, artificial lighting such as street lights have been placed on roadways and in parking lots to improve night visibility for motorists. However, artificial lighting is not always sufficient for motorists and individuals so alternatives for improving night visibility have been established. 
         [0006]    For example, one method for designing fixed roadway lighting promulgated by the American Standards Institute (ANSI) and Illuminating Engineering Society of North America (IESNA) is termed “Small Target Visibility” and is a method for maximizing the visibility of small (7 inch square) targets on a roadway. However, with this method all objects are still not detectable because there is not enough contrast between the object and background. 
         [0007]    There is a desire to optimize headlamp and fixed roadway lighting system interactions to improve visibility. Other systems include aesthetic “under vehicle” lighting as well as variably aimed headlamps wherein both provide some assistance in detecting roadway hazards. These existing lighting systems, while beneficial, use large amounts of power and hence are costly. There is a need for a lighting system that further improves visibility at night on roadways and other artificially lit areas while also being cost effective. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention solves the above-described problem by providing a variable lighting system (“VLS”) for optimizing object visibility at night. The VLS varies the intensity of the variable lighting element to improve the contrast of objects. Contrast or luminance contrast is the relationship between the luminance of a brighter area of interest and that of an adjacent darker area. Mathematically, it is known as the Weber Contrast and is defined as the absolute value of difference between the two luminances divided by the lower luminance or |(Lo-Lb)/Lb|, with Lo typically representing the luminance of objects and Lb typically representing the luminance of the background. 
         [0009]    Contrast sensitivity is the ability to discern between luminosities of different levels in a static image. Contrast sensitivity varies between individuals, maxing out at approximately 20 years of age, and at spatial frequencies of about 2-5 cycles/degree. In addition it can decline with age and other factors such as cataracts and diabetic retinopathy. A Contrast Threshold is the minimal amount of contrast, or difference between two shades of objects, needed in order to detect a pattern. Contrast threshold is measured by the number of photons a light stripe reflects in comparison to the number of photons reflected in a dark stripe. The contrast threshold is used to find the contrast sensitivity function, which is defined by taking the reciprocal of the contrast threshold. 
         [0010]    In the prior art relative to fix roadway lighting, the contrast of the target and background is established by geometric factors does not change. Thus if an object is below the contrast threshold it will stay in the non-contrast threshold and be non-visible. For example, for a first certain location, such as between two light poles Lb, may be 1 candela/meter̂2 while at a second location the background luminance may be 5 candela/meter̂2. In the prior art, the intensity of the illumination on the object and the background is relatively constant and therefore, the contrast is relatively constant. Hence, the contrast may be acceptable for the first location but not for the second location. In the prior art, as a vehicle drives on a roadway with light poles, the vehicle is continually driving though positive contrast and negative contrast areas. 
         [0011]    The VLS varies the intensity of the illumination on the object and background to vary the luminance of the object Lo and the background Lb so that the maximum available contrast for a person with average contrast sensitivity can be obtained at some point in the variable illumination cycle. The VLS comprises a variable lighting element, and a master synchronizer for synchronizing the timing and sequence of the variable lighting. The variable lighting element cycles through a range of lighting intensities so that any objects illuminated by the variable lighting element and the background will have a variable luminance. The luminance of the object, Lo, and the background Lb are varied such that a contrast above threshold can be obtained at every location along a roadway. It is understood that as the luminance is varied, an contrast below threshold may be obtained and the transition from the maximum contrast to the minimum contrast and the frequency of the maximum contrast (or minimum contrast) will depend on frequency that the intensity of the illumination varies. The contrast may be positive contrast where the Lo is greater than Lb or the contrast may be negative contrast where Lb is greater than Lo. 
         [0012]    In one embodiment, a VLS is on two or more lighting fixtures such as light poles, street lamps, or indoor lighting and the varying intensity of the illumination from each VLS is synchronized to produce a maximum Weber Contrast. For example, a first VLS may have a high lighting intensity in the north direction and a second VLS may have a low lighting intensity in the south direction. Looking north, any objects illuminated by the first VLS would have a relatively high luminance Lo and the background luminance Lb from the second VLS would be relatively low thereby producing a relatively high Weber Contrast. Then each VLS cycles through a range of lighting intensities such that the first VLS may have a low lighting intensity in the north direction while the second VLS has a high lighting intensity in the south direction. Again looking north, any objects illuminated by the first VLS would have a relatively low luminance Lo and the background luminance Lb would be relatively high. Therefore, using the contrast formula |(Lo-Lb)/Lb| the contrast would be relatively high. 
         [0013]    In another embodiment, a VLS is on one or more lighting fixtures and vehicle contains a non-varying illumination source wherein the varying intensity of the illumination from each VLS is synchronized to product a maximum Weber Contrast. For example, as the vehicle is traveling north, the illumination source on the vehicle has a relatively high lighting intensity in the north direction so any objects would have a relatively high luminance Lo. The closest VLS on a lighting fixture would have a low lighting intensity in the south direction to produce a relatively low background luminance Lb and thereby produce a relatively high Weber Contrast. 
         [0014]    Also, the closest VLS may have a low lighting intensity in the north direction while a second VLS north of the closest VLS to the vehicle would have a high lighting intensity in the south direction. The second VLS north of the closest VLS to the vehicle would be beyond the illumination range of the illumination source on the vehicle so any objects illuminated by the closest VLS would have a relatively low luminance Lo and the background luminance Lb produced by the second VLS north of the closest VLS to the vehicle would be relatively high. Then, to prevent a wash out, or the background luminance Lb matching the object luminance Lo, as the vehicle travels north and the illumination range of the illumination source on the vehicle approaches the second VLS, the lighting intensity in the south direction of the second VLS would decrease as the lighting intensity in the north direction would increase from the illumination source of the vehicle. In one embodiment, the vehicle contains a VLS and the VLS on the vehicle is synchronized with each VLS on the lighting fixture to produce a high Weber Contrast. 
         [0015]    In another embodiment, at least one VLS is on a vehicle and as the vehicle travels, the intensity of the illumination is varied to obtain a maximum Weber Contrast. The vehicle with the VLS may contain a sensor that determines the luminance of the background and adjusts the intensity of the illumination from the VLS to obtain a maximum Weber Contrast. For example, if the vehicle is traveling north and the background luminance Lb is relatively low, then the illumination from the VLS on the vehicle would be relatively high such that any objects within the illumination range of the VLS would have a relatively high object luminance Lo thereby producing a relatively high Weber Contrast. Then, as the vehicle travels into an area where the background luminance Lb is relatively high, the illumination from the VLS on the vehicle would be relatively low such that any objects within the illumination range of the VLS would have a relatively low object luminance Lo thereby producing a relatively high Weber Contrast. 
         [0016]    In one embodiment, the VLS varies the intensity and the color of the illumination on the object to vary the intensity and color of the luminance of the object Lo as well as the intensity and color of the background such that the maximum available contrast for a person with average contrast sensitivity can be obtained. In existing lighting systems, neither color or intensity changes and object luminance Lo and background luminance Lb remain constant and therefore the contrast does not change. If an object is in the non-visible region, it will stay in the non-visible region. 
         [0017]    When color is added, the Weber Contrast formula becomes modified such that the contrast is now defined as |(Lo-Lb)/Lb|+the color contrast metric. The color contrast metric is difficult to quantify because the discriminability of pairs of colors depends on their differences in chrominance and luminance. While an entirely satisfactory metric does not exist that combines these attributes into a single assessment of total color difference, an estimate can be derived by calculating the weighted difference between the locations of the colors in the 1976 CIE UCS (CIE UCS L*u*v*). In addition, the specification of small color differences should be treated with caution due to the inherent lack of color uniformity on most devices. Further information regarding the color contrast metric can be found at: American national standard for human factors engineering of visual display workstations, American National Standards Institute (1988) Santa Monica, Calif.: Human Factors and Ergonomics Society; A literature review and experimental plan for research on the display of information on matrix-addressable displays, Decker, J. J., Pigion, R. D., &amp; Snyder, H. L. (1987) Blacksburg, Va.: Human Engineering Laboratory, VPI &amp; SU; and Color contrast metrics for complex images, Post, D. L., &amp; Snyder, H. L. (1986). Blacksburg, Va.: Human Factors Laboratory, VPI &amp; SU (DTIC No. AD-A174960) all three of which are incorporated herein by reference. 
         [0018]    In one embodiment, the system changes color and light intensity thereby providing a color contrast in addition to the Weber Contrast. The variation of intensity and color is designed to be quick enough to allow detection and reaction yet slow enough to be visually discrete to move the target into the visible range. In one embodiment, the variation is at least every 0.6 seconds. 
         [0019]    In another embodiment, the VLS varies light intensity, color, and direction and optionally includes a detector for detecting motion, noise, or other occurrences. The VLS can be implemented as a fixed lighting source, a movable lighting source, or a vehicle mounted lighting source. The VLS improves visibility at night for all viewers, particularly bicycle riders, pedestrians, and motorists thereby reducing accidents and damage costs and saving lives. Furthermore when compared to known lighting systems, the VLS saves energy, improves the environment, and enhances quality of life by reducing light pollution and light trespass. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0020]    The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein: 
           [0021]      FIG. 1  is a perspective view illustrating the variable lighting system of the present invention; 
           [0022]      FIG. 2  is a flow chart depicting the steps involved in synchronizing the clock of the present invention; and 
           [0023]      FIG. 3  is a flow chart depicting the steps involved in synchronizing the timing sequence of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized. It is also to be understood that structural, procedural and system changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents. For clarity of exposition, like features shown in the accompanying drawings are indicated with like reference numerals and similar features as shown in alternate embodiments in the drawings are indicated with similar reference numerals. 
         [0025]      FIG. 1  shows variable lighting system (“VLS”)  102  for optimizing object visibility at night. VLS  102  contains variable lighting element  108  and synchronizer  110 . Variable lighting element  108  is an illumination source and the illumination from variable lighting element  108  can be varied in any given direction. The direction of illumination may be in one direction, such as north, two directions such as north-south, or more such as north-east-south-west directions. For example, to vary the direction of illumination when using one light source and two directions, the variability is provided by an increase in the light intensity emitted in the northward direction, then a decrease in the intensity emitted northward with an increase in the intensity emitted in the southward direction, then a decrease in the intensity emitted southward which is followed by a repeat of the cycle again piecewise-continuously. The cycle frequency itself may be at a steady interval, such as every 0.5 seconds, or variable and can be any frequency greater than about 1/250th of a second, or the smallest amount of flicker the eye can detect. In one embodiment, the cycle frequency is about 0.5 seconds. 
         [0026]    To vary the illumination from one illumination source in more than two directions, for example, north-east-south-west, the light intensity emitted by the source in the northward direction is increased; then the intensity in the northward direction is decreased and the intensity in the eastward direction is increased; then the intensity in the eastward direction is decreased and the intensity in the southward direction is increased; then the intensity in the southward direction is decreased and the intensity in the westward direction is increased; then the intensity in the westward direction is decreased and the intensity emitted northward is increased; and the cycle is then repeated piecewise-continuously. The cycle does not need to be continuously clockwise or counterclockwise and may be in any order or sequence and may be variable. In addition, more than one direction may have the same intensity at any time. The length of the “on,” “off,” “increase,” or “decrease” cycle of any direction need not be the same as other directions “on,” “off,” “increase,” or “decrease” cycle times and may also be variable in any and all directions. The cycle frequency itself may be at a steady interval, such as every 0.5 seconds, or variable and can be any frequency greater than about 1/250th second, or the amount of flicker the eye can detect. In one embodiment, the cycle frequency is about 0.5 seconds. 
         [0027]    Variable lighting element  108  varies the intensity of the illumination on the object and background to vary the luminance of the object Lo and the background Lb so that the maximum available contrast for a person with average contrast sensitivity can be obtained at some point in the variable illumination cycle. Contrast or luminance contrast is the relationship between the luminance of a brighter area of interest and that of an adjacent darker area. Mathematically, it is known as the Weber Contrast and is defined as the absolute value of difference between the two luminances divided by the lower luminance or |(Lo-Lb)/Lb|, with Lo typically representing the luminance of objects and Lb typically representing the luminance of the background. 
         [0028]    Variable lighting element  108  cycles through a range of lighting intensities so that any objects illuminated by the variable lighting element will have a variable luminance. The luminance of the object, Lo, is varied such that an acceptable contrast can be obtained whatever the background luminance may be. It is understood that as the luminance is varied, an unacceptable contrast will be obtained and the transition from the maximum acceptable contrast to the maximum unacceptable contrast and the frequency of the maximum acceptable contrast (or minimum acceptable contrast) will depend on frequency that the intensity varies. The contrast may be light contrast where the Lo is greater than Lb or the contrast may be dark contrast where Lb is greater than Lo. 
         [0029]    In one embodiment, VLS  102  is on two or more lighting fixtures such as light poles, street lamps, or indoor lighting. The varying intensity of the illumination from each variable lighting element  108  on each VLS  102  is synchronized to produce a maximum Weber Contrast. For example, a first VLS  102  may have a high lighting intensity in the north direction and a second VLS  102  may have a low lighting intensity in the south direction. Looking north, any objects illuminated by first VLS  102  would have a relatively high luminance Lo and a relatively low background luminance Lb would be provided by second VLS  102 , thereby producing a relatively high Weber Contrast. Then each VLS  102  cycles through a range of lighting intensities such that the first VLS  102  may have a low lighting intensity in the north direction while the second VLS  102  has a high lighting intensity in the south direction. Again looking north, any objects illuminated by the first VLS would have a relatively low luminance Lo and a relatively high background luminance Lb provided by second VLS  102 , thereby, using the contrast formula |(Lo-Lb)/Lb|, the Weber Contrast would be relatively high. 
         [0030]    In another embodiment, a VLS  102  is on one or more lighting fixtures and vehicle  112  contains non-varying illumination source  104 . In one embodiment, illumination source  104  is headlights. In another embodiment, illumination source  104  is a combination of headlights or other light sources in the front of, rear lights sources in the back of, and light sources such as LEDs or other light sources on the side of vehicle  112 . The varying intensity of the illumination from each variable lighting element  108  on each VLS  102  is synchronized to product a maximum Weber Contrast. For example, as vehicle  112  is traveling north, illumination source  104  on vehicle  112  has a relatively high lighting intensity in the north direction so any objects illuminated by illumination source  104  on vehicle  112  would have a relatively high luminance Lo. The variable lighting element  108  on the VLS  102  that is north and closest to vehicle  112  would have a low lighting intensity in the south direction to produce a relatively low background luminance Lb and thereby produce a relatively high Weber Contrast. 
         [0031]    Also, the closest variable lighting element  108  to vehicle  112  may have a low lighting intensity in the north direction while a second variable lighting element  108  on a VLS  102  north of the closest VLS  102  to vehicle  112  would have a high lighting intensity in the south direction. The second VLS  102  that is north of the VLS  102  closest to vehicle  112  would be beyond the illumination range of illumination source  104  on vehicle  112  so any objects illuminated by variable lighting element  108  on the closest VLS  102  would have a relatively low luminance Lo and the background luminance Lb produced by the second variable lighting element  108  on the VLS  102  north of the closest VLS  102  to vehicle  112  would be relatively high. Then, to prevent a wash out, or the background luminance Lb matching the object luminance Lo, as vehicle  112  travels north and the illumination range of illumination source  104  approaches the second VLS  102 , the lighting intensity of variable lighting element  108  on the second VLS  102  in the south direction would decrease as the lighting intensity in the north direction would increase from the illumination source of vehicle  112 . In one embodiment, vehicle  112  contains at least one variable lighting element  108  and variable lighting element  108  on the vehicle  112  is synchronized with each VLS  102  on the lighting fixture to produce a high Weber Contrast. 
         [0032]    In another embodiment, at least one variable lighting element  108  is on vehicle  112  and as vehicle  112  travels, the intensity of the illumination is varied to obtain a maximum Weber Contrast. In one embodiment, vehicle  112  contains sensor  114  that determines the luminance of the background and adjust the intensity of the illumination from at least one variable lighting element  108  to obtain a maximum Weber Contrast. For example, if vehicle  112  is traveling north and the background luminance Lb is relatively low, then the illumination from at least one variable lighting element  108  on vehicle  112  would be relatively high such that any objects within the illumination range of at least one variable lighting element  108  would have a relatively high object luminance Lo thereby producing a relatively high Weber Contrast. Then, as vehicle  112  travels into an area where the background luminance Lb is relatively high, the illumination from at least one variable lighting element  108  on vehicle  112  would be relatively low such that any objects within the illumination range of at least one variable lighting element  108  would have a relatively low object luminance Lo thereby producing a relatively high Weber Contrast. 
         [0033]    In another embodiment, vehicle  112  contains a side and/or rear mounted variable lighting element  108 . The side and/or rear mounted variable lighting element  108  may be almost any intensity that is safe for the environment it is being used in. Compared to headlamps which illuminate only in the front, but not necessarily toward the roadway, the illumination from the side and/or rear mounted variable lighting element  108  may be emitted toward the roadway or any other direction away from vehicle  112  and may be variable. For example, as the speed increases, the illumination may be directed further away from vehicle  112  and as vehicle  112  decelerates the illumination may be directed closer to vehicle  112  towards the roadway. Variable lighting element  108  may also be at least partially directed towards vehicle  112  to illuminate vehicle  112 . The side and rear mounted variable lighting element  108  provide visibility of objects for others outside vehicle  112  such as other motorists, pedestrians, cyclists, cameras, or other vehicle detectors and to also improve the visibility and identity of the vehicle itself. 
         [0034]    Each VLS  102  also comprises synchronizer  110 . Synchronizer  110  coordinates the timing and sequence of all variable lighting element  108  on each VLS  102 . Synchronizer  110  provides a timing coordination signal so that directional variability and intensity from each variable lighting element  108  may work together in harmony so that each variable lighting element  108  will increase or decrease intensity to create the maximum available Weber Contrast. 
         [0035]    Synchronizer  110  may generate timing signals to coordinate the timing and sequence of the lighting intensity and direction of illumination from variable lighting element  108 . Each synchronizer  110  contains a clock that is synchronized with a standard timing device or another synchronizer  110  in the area. The standard timing device may be any standard timing device known in the art or may be the AC sine wave located on every power line and generated from the electrical plant supplying electricity to the area. To synchronize the clocks, the frequency of the sine wave is measured and used to create a standard of time. Any other device that can access the sine wave can use the sine wave to create the same standard of time. 
         [0036]    The sequence of the lighting intensity and direction of illumination from variable lighting element  108  is preprogrammed in each VLS  102  and may be hardwired or rewritable. In one embodiment, synchronizer  110  may overridden by detector  114  such as if detector  114  is on vehicle  112  or a street lamp and is measuring the background luminance Lb and overrides synchronizer  110  to produce the maximum available Weber Contrast. 
         [0037]    In one embodiment, synchronizer  110  emits a wireless synchronization signal to objects such as vehicles or other components not connected to the standard timing device so that any VLS  102  that cannot access the standard timing device can be synchronized with any other VLS  102  in the vicinity. In addition, synchronizer  110  emits a timing signal that includes the sequence of the lighting intensity and direction of illumination from variable lighting element  108 . Also, all synchronizers  110  are equipped with priority codes so that one synchronizer acts as a master synchronizer for a given area and the wireless synchronization signal and timing signal are used by all the VLS  102  in the area. 
         [0038]    In one embodiment, VLS  102  varies the intensity and the color of the illumination on the object to vary the intensity and color of the luminance of the object Lo as well as the intensity and color of the background such that the maximum available contrast for a person with average contrast sensitivity can be obtained. When color is added, the Weber Contrast formula becomes modified such that the contrast is now defined as |(Lo-Lb)/Lb|+the color contrast metric. VLS  102  changes color and light intensity thereby providing a color contrast in addition to the Weber Contrast. The variation of intensity and color is designed to be quick enough to allow detection and reaction yet slow enough to be visually discrete to move the target into the visible range. In one embodiment, the variation is at least every 0.6 seconds. In another embodiment, vehicle  112  contains sensor  114  that determines the intensity and color of the background luminance and adjust the intensity and color of the illumination from at least one variable lighting element  108  to obtain an object luminance that will give a maximum Weber Contrast and color contrast metric. 
         [0039]    The light emitted in a given direction may be any color or a combination of colors. For example, red light may be emitted northward, then dimmed and then green light increasingly emitted northward as the red light is dimmed and then the red light increasingly emitted northward as the green light is dimmed. Also, similar light patterns may be emitted southward either at the same time or at a subsequent time period synchronized with the light that is being emitted in another direction. For example, red light may be emitted northward while green light is emitted southward. Then the northward red light is dimmed and green light is increasingly emitted northward while the green southward light is dimmed and the red light is increasingly emitted southward. The variable lighting system of the above example provides a varying color and intensity contrast of red and green. This will provide better contrast compared to the method of intensity contrast, thereby increasing visibility. The color emitted north and south is typically not the same color at the same time. In one embodiment, the emitted colors are complimentary colors. 
         [0040]    A similar cycle may occur if more than two directions and/or more than two colors are used. For example, a red light may be emitted northward, a blue light eastward, a green light southward, and a yellow light westward. Then the red light is dimmed and the blue light is increasingly emitted northward while the blue eastward light is dimmed, the green light is increasingly emitted eastward while the green southward light is dimmed, the yellow light is increasingly emitted southward while the yellow westward light is dimmed, and the red light is increasingly emitted westward. The general cycle is repeated piecewise-continuously. The cycle does not need to be continuously clockwise or counterclockwise and may be in any order or sequence and may be variable. Also, more than one color may be emitted at one time. The length of the “on,” “off,” “increase,” or “decrease” cycle of any direction need not be the same as other directions “on,” “off,” “increase,” or “decrease” cycle times and may also be variable. The cycle frequency itself may be at a steady interval, such as every 0.5 seconds, or variable and can be any frequency greater than approximately 1/250th second, or the amount of flicker the eye can detect. Preferably, the cycle frequency is about 0.5 seconds. In one embodiment, only even numbered directions are used, such as two, four, six, or eight. In another embodiment, each VLS is coordinated such that the color illuminating an object is a complement of the background color to increase contrast. 
         [0041]    Synchronizer  110  provides a timing coordination signal so that directional variability for each color and intensity from each variable lighting element  108  may work together in harmony so each variable lighting element  108  will increase or decrease intensity and change color to create the maximum available Weber Contrast and color contrast metric. 
         [0042]    Synchronizer  110  may generate timing signals to coordinate the timing and sequence of the lighting intensity, color, and direction of illumination from variable lighting element  108 . In one embodiment, synchronizer  110  emits a timing signal that includes the sequence of the lighting intensity, color, and direction of illumination from illumination source  104  and variable lighting element  108 . 
         [0043]    In another embodiment, VLS  102  includes illumination source  104 , variable lighting element  108 , and may contain synchronizer  110 . The illumination range of base element  104  can range from zero to 100 million candle power and may be variable. Preferably the minimum illumination level is the lowest illumination detectable by the human eye based on the surrounding environment and the maximum illumination level is the maximum amount of illumination that would be safe for the surrounding environment. Illumination source  104  can be configured to consist of light energy in one, a portion of, or all of the visible wavelengths (anything from mono-chromatic to white light). In addition to the illumination from illumination source  104 , if any, variable lighting element  108  adds varying amounts of illumination, color, and/or light direction. 
         [0044]    VLS  102  may be implemented as fixed lighting sources or a mobile lighting source. Fixed lighting sources include lights on street light poles, in parking lots or on buildings. Mobile VLS  104  includes any VLS mounted on mobile source such as vehicle  112 . In one embodiment, vehicle  112  mounted VLS  102  includes at least one illumination source  104  and at least one variable lighting element  108 . One illumination source  104  and/or one variable lighting element  108  may be mounted on the front of vehicle  112  similar to headlamps. The at least one illumination source  104  and at least one variable lighting element  108  may be mounted on the side and/or rear of vehicle  112 . 
         [0045]    In one embodiment, synchronizer  110  on vehicle  112  synchronizes the lighting system of vehicle  112  by using any available standard timing device or the wireless synchronization signal emitted from synchronizer  110  of VLS  102 . The standard timing device is static and typically will have priority over the wireless synchronization signal. Exceptions to the priority may include emergency vehicles or other special events. 
         [0046]    In the case of an emergency vehicle or other special event, the emergency vehicle or some other source will send a priority signal that will override the lighting pattern of VLS  102  and variable lighting element  108 . For example, if a police car or fire engine is speeding to an accident or fire, then all static VLS  102  within a two-block radius may flash a red light. Also, all variable lighting elements  108  in the direction of the speeding car or fire engine may flash their lights. This would alert all drivers and pedestrians that a police or fire engine is in their area and the drivers and pedestrians should take the appropriate action. 
         [0047]      FIG. 2  depicts a method of using the VLS  102 . When the VLS  102  is first activated, Step  200 , the synchronizer  110  checks to determine if there is a master synchronizer  110  to synchronizes the clock in the synchronizer  110 , Step  202 . If there is a master synchronizer  110 , the synchronizer  110  uses the master synchronizer  110  to synchronize its clock, Step  204 . If there is not a master synchronizer  110 , the synchronizer  110  checks to determine if there is a standard timing device to synchronizes the clocks in the synchronizer  110 , Step  206 . If there is a standard timing device, such as the AC sine wave described above, the synchronizer  110  uses the master or standard timing device to synchronize its clock, Step  208 . If there is not a standard timing device, then the synchronizer  110  determines if there is a lower priority synchronization signal such as a wireless synchronization signal from a synchronizer  110  that is not a master synchronizer  110 , Step  210 . If there is a lower priority synchronization signal, the synchronizer  110  uses that synchronization signal to synchronize its clock, Step  212 . Steps  202  through  212  allow all the clocks of any VLS  102  within a given area to be to be synchronized. If there is not a lower priority synchronization signal, then the synchronizer  110  uses the last clock setting available, such as a factory clock setting or the last synchronized clock setting, Step  214 . After the clock is synchronized, the synchronizer  110  sends out a wireless synchronization signal, Step  216 . 
         [0048]    Next, as shown in  FIG. 3 , the synchronizer  110  checks to determine if there is a master timing signal from a master synchronizer  110  to synchronizes the timing and sequence of the lighting intensity, color, and direction of illumination from illumination source  104  and variable lighting element  108 , Step  302 . If there is a master timing signal, the synchronizer  110  uses the master timing signal to synchronize the timing and sequence of the lighting intensity, color, and direction of illumination from illumination source  104  and variable lighting element  108 , Step  304 . If there is not a master timing signal, the synchronizer  110  checks to determine if there is a lower priority timing signal such as a wireless timing signal from a synchronizer  110  that is not a master synchronizer  110 , Step  306 . If there is a lower priority timing signal, synchronizer  110  uses that timing signal to synchronize the timing and sequence of the lighting intensity, color, and direction of illumination from illumination source  104  and variable lighting element  108 , Step  308 . Steps  302  through  308  allow all the timing and sequence of the lighting intensity, color, and direction of illumination from illumination source  104  and variable lighting element  108  for each VLS  102  within a given area to be to be synchronized. If there is not a lower priority timing signal, then the synchronizer  110  uses the preprogrammed timing signal for the timing and sequence of the lighting intensity, color, and direction of illumination from illumination source  104  and variable lighting element  108 . After the timing sequence is established, the synchronizer  110  sends out a wireless timing signal, Step  312 . 
         [0049]    For example, vehicles driving in the north direction may receive a timing signal to emit blue lights at a frequency of 0.5 seconds northward and vehicles traveling in the south direction may receive a timing signal to emit green light at a frequency of 0.5 seconds southward. The lighting difference provides the increased contrast necessary to see more objects in the roadway. 
         [0050]    A vehicle mounted variable lighting element  108  may be programmed such that if no other vehicle is within a predetermined range, such as approximately 1000 to 1500 feet, then no side and rear vehicle lighting is emitted. The range may be established by the detection of a wireless signal from detector  114 . 
         [0051]    In one embodiment, detector  114  can also detect a predetermined signal such as one from an emergency vehicle, motion detector, noise detector, distress signal, traffic signal, or other unrelated occurrence. If the detector is activated, the VLS  110  may noticeably modify the light emission to produce a flash, flash red, or other color, or produce some other noticeable change. The VLS  102  response to a predetermined signal may vary with the source of signal. For example, the VLS  102  may produce a red tint appearance when a traffic signal ahead is red, red flash overtones when an emergency vehicle is nearby, or flash yellow overtone when a lane is closed or other trouble is ahead. Also, fixed lighting may be turned off or dimmed when no vehicles are present or are not in close enough proximity to be of sufficient value to warrant the illumination. This could save on the overall cost of operating a fixed lighting system. 
         [0052]    Preferred forms of the invention have been shown in the drawings and described above, but variations in the preferred forms will be apparent to those skilled in the art. For example, the VLS  102  may be used inside a building. The preceding description is for illustration purposes only, and the invention should not be construed as limited to the specific form shown and described. The scope of the invention should be limited only by the language of the following claims.