Stud for Roads

Abstract

A road marker 20 comprises a body 22. A photodetector 26 mounted on the body is responsive to illumination by headlights of a first vehicle approaching the body. The photodetector is connected in a circuit 32 on the body also comprising a light emitting device 30. The circuit being configured to energize the light emitting device upon illumination of the photodetector by the head lights of a vehicle approaching the body in a first direction A and the light emitting device is mounted on the body to enhance visibility of the body, particularly for a driver of a second vehicle being driven in a direction B other than the first direction.

1 . A road sign ( 20 ,  40 ,  50 ,  80 ) comprising: 
 a body ( 22 ,  42 ,  56 ,  85 );    a photodetector ( 26 ,  84 ) on the body,    the photodetector being configured on the body to be sensitive to illumination by headlights of a first vehicle ( 16 ) approaching the body in a first direction;    the photodetector being connected in a circuit ( 32 ,  68 ) on the body also comprising a light emitting device ( 30 ,  58 . 1 ,  86 );    the circuit being configured to energize the light emitting device in response to illumination of the photodetector by the head lights of the first vehicle ( 16 ); and    the light emitting device ( 30 ,  58 . 1 ,  86 ) being mounted on the body to enhance visibility of the body ( 22 ,  42 ,  56 ,  85 ) for a driver of a second vehicle ( 18 ) being driven in a direction (B) other than the first direction (A).    
   
   
       2 . A road sign as claimed in  claim 1 , wherein the body comprises the body of a vehicle carrying the sign.  
   
   
       3 . A road sign as claimed in  claim 1 , wherein the sign is in the form of a road side marker.  
   
   
       4 . A road sign as claimed in  claim 1 , wherein the sign is a road surface mountable stud and wherein the body is configured to be mounted on a road surface.  
   
   
       5 . A road sign as claimed in  claim 1 , wherein the photodetector is a photoswitch connecting the light emitting device to a power supply.  
   
   
       6 . A road sign as claimed in  claim 5 , wherein the power supply is externally of the body.  
   
   
       7 . A road sign as claimed in  claim 5 , wherein at least part of the power supply is mounted on the body of the sign.  
   
   
       8 . A road sign as claimed in  claim 5 , wherein the power supply comprises a photosensitive power source and a charge storage device.  
   
   
       9 . A road sign as claimed in  claim 1 , wherein the photodetector is connected to the light emitting device to act as power supply and to power the light emitting device upon illumination of the photodetector.  
   
   
       10 . A road sign as claimed in  claim 9 , wherein a photoswitch is connected in the circuit with the photodetector and the light emitting device.  
   
   
       11 . A road sign as claimed in  claim 1 , wherein the photodetector is mounted on one sidewall of the body and the light emitting device is mounted on another sidewall of the body.  
   
   
       12 . A road sign as claimed in  claim 11 , wherein a retro-reflector is mounted on at least one of said one sidewall and said other sidewall of the body.  
   
   
       13 . A road sign as claimed in  claim 1 , wherein the light emitting device transmits light in one of the red, orange and green parts of the visible spectrum.  
   
   
       14 . A method of signaling to traffic on a road, the method comprising the steps of; 
 providing a road sign ( 20 ) comprising a body ( 22 ) carrying a photodetector ( 26 ) and an electrical circuit ( 32 ) connecting the photodetector to a light emitting device ( 30 ) on the body;    utilizing impinging light emitted by headlights of a first vehicle ( 16 ) traveling in a first direction (A) to cause the photodetector to cause energization of the light emitting device; and    causing the light emitting device to emit light in a direction wherein visibility of the body ( 22 ) is enhanced for a driver of another vehicle ( 18 ) which is being driven in a direction (B) other than the first direction (A).