GB2260437A

GB2260437A - Vehicle safety

Info

Publication number: GB2260437A
Application number: GB9221176A
Authority: GB
Inventors: John Owen Hounsell
Original assignee: EMMANUEL ENTERPRISES Ltd
Current assignee: EMMANUEL ENTERPRISES Ltd
Priority date: 1991-10-09
Filing date: 1992-10-08
Publication date: 1993-04-14
Also published as: GB9221176D0; GB9121363D0

Abstract

Indication of whether separation from a vehicle 17 ahead is safe or otherwise is given to the driver of a following vehicle 10 by transmitting two light beams 14 forwardly from that vehicle 10 onto an elongate retro-reflector 1 mounted across the back of the vehicle 17 ahead. The reflector 1 has a central, red zone 2, two amber zones 3 flanking the red zone 1 and two outer, green zones 4, and the angular directions of the transmitted beams 14 are varied by a unit 15 according to the speed of the following vehicle 10 so that their points of incidence on the reflector 1, and therefore the colours reflected, are dependent upon both the speed of the following vehicle 10 and its separation from the vehicle 17 ahead. The beam angle may be varied in accordance with steering of the following vehicle 10. The light transmitted may be infra-red instead of visible, in which case the reflector may be replaced by a detector actuating a transmitter of visible or infra-red light (if infra-red, the following vehicle 10 has a detector actuating an indicator and/or alarm). <IMAGE>

Description

Vehicle Safety This invention relates to vehicle safety.

The invention is especially concerned with vehicle safety systems and methods for assisting in the maintenance of safe vehicle-to-vehicle separation.

According to one aspect of the present invention a vehicle safety system for assisting in the maintenance of safe vehicle-to-vehicle separation includes means for transmitting beams of light forwardly from a vehicle, and means for varying the angular directions of the beams according to vehicle speed so that the points of incidence of the beams on a vehicle ahead are dependent upon both said vehicle speed and the vehicle-to-vehicle separation.

According to another aspect of the present invention there is provided a method for assisting in the maintenance of safe separation between two vehicles travelling one following the other, wherein beams of light are transmitted forwardly from the following vehicle to be incident on the vehicle ahead, and the angular directions of the transmitted beams are varied according to the speed of the following vehicle so that their points of incidence on the vehicle ahead are dependent upon both the speed of the following vehicle and its separation from the vehicle ahead.

The light beams transmitted in the system and method may be beams of visible light and in these circumstances indication of whether the vehicle-to-vehicle separation is safe or otherwise may be obtained using reflector means which is carried by the vehicle ahead and which is divided into zones for providing one or another of at least two different visual indications according to the locations of the points of incidence of the light beams on such means. Infra-red, rather than visible, light may be used, and in this case the vehicle ahead may carry a unit that responds to the incident beams to provide a visible-light or infra-red response dependent on such locations.

A vehicle safety system and method for assisting in the maintenance of safe vehicle-to-vehicle separation, in accordance with both aspects of the present invention, will now be described, by way of example, with reference to the accompanying drawing, in which: Figure 1 shows a reflector used in the system and method of the invention; and Figure 2 illustrates beam-transmitting equipment as carried by a typical vehicle involved in the system and method of the invention.

Referring to Figure 1, each vehicle using the system is fitted with a elongate reflector 1 that is mounted centrally and to extend laterally of the rear-end of the vehicle (for example, mounted along or just above the rear bumper or fender). The reflector 1, which is retroreflective, is divided into five coloured zones, namely a central, red zone 2, two smaller, amber zones 3 flanking the red zone 2, and two outer, green zones 4 flanking the amber zones 3. Thus, according to the zone in which white light is incident on the reflector 1, the reflection is coloured red, amber or green.

In the latter respect, each vehicle is equipped to direct two narrow beams of generally-white light forwardly from its front-end such that if this vehicle is following another, the beams are incident on the reflector 1 of that other vehicle. The beams illuminate the red zone 2, the pair of amber zones 3, or the pair of green zones 4 of the reflector 1 in dependence upon the speed of the following vehicle and the distance separating it from the vehicle in front. The driver of the following vehicle consequently receives return reflections that are red, amber or green according to whether the separation distance is, respectively, dangerous, unsafe or safe, and can take whatever action is appropriate. The equipment involved in a typical vehicle is illustrated in Figure 2, and will now be described.

Referring to Figure 2, the vehicle 10 is equipped with two light-beam sources 11 that are mounted spaced apart from one another symmetrically of its front-end 12. The sources 11 are mounted to pivot about vertical axes 13 and to produce forwardly-directed light-beams 14 that toe inwardly towards one another to an extent dependent upon vehicle speed. To this end, the pivotal angle of each source 11 is regulated by a unit 15 that is responsive to the vehicle speed such that as the speed increases the cross-over point 16 of the beams 14 shifts further ahead of the front-end 12 of the vehicle 10.

If, as illustrated in Figure 2, the vehicle 10 is following another vehicle 17 and the points of incidence of the light beams 14 on the reflector 1 of the vehicle 17 are within the green zones 4, the driver of the vehicle 10 will be assured by the green-light reflection that the vehicle-to-vehicle separation distance is appropriate for his speed. However, if the separation distance is less, with the vehicle 10 located closer to the vehicle in front, as illustrated by chain-dotted line 17' within a range identified as UNSAFE, the beams 14 are incident on the reflector 1 in the two zones 3, giving an amber-reflection warning. If the vehicle 10 is even closer, as illustrated by broken line 17" within a range identified as DANGEROUS, the beams 14 are both incident within the central zone 2 so as to give the driver a redreflection warning.

The driver may respond to the amber- or red-light warning received, by reducing speed so that the separation distance required for safety, is reduced; if the speed of the vehicle ahead remains the same, this reduction in speed will also be accompanied by an increase in the actual separation. The unit 15 responds to the reduction in speed to pivot the light sources 11 inwardly about the axes 13, shifting the cross-over point 16 of the beams 14 closer in to the vehicle 10. Provided the actual separation between the vehicles is not decreasing (as might occur, for example, if the vehicle ahead is slowing down), the points of incidence of the beams 14 on the reflector 1 will thus move further apart until, with time, they enter the green zones 4 to indicate that the vehicle-to-vehicle separation is appropriate for the current speed of the vehicle 10. The movement will be augmented by any increase in the actual separation distance and the reduction in the safe-separation distance which accompanies reduction of speed.

Each light source 11 is required to produce a narrow, parallel beam, and in this respect may involve a laser and/or fibre optics. Furthermore, instead of mounting the sources 11 to pivot, they may be fixed, and the required variation in angular direction of the beams 14 produced by pivotal movement of associated mirrors, lenses or other optical elements. The pivotal movements of the sources 11, or of associated optical elements, may be effected by cable- or other mechanical-drive from the unit 15, or may be brought about electrically (for example, by synchro control). The unit 15 may be driven from the speedometer of the vehicle or from a tachometer that produces an electrical signal in accordance with vehicle speed.

The operation of the system is described above without taking into account the way in which safe vehicle-tovehicle separation varies according to weather or other road conditions, and on the assumption that the vehicles are following one behind the other along a straight path.

The system may include provision for input to the unit 15 dependent on road condition and curve of the road, so that adjustment to beam angle is made automatically by the unit 15 to take account of such factors. More particularly, an electrical signal in accordance with road conditions can be supplied to the unit 15 from sensors mounted on the vehicle or from one or more controls set by the driver. Furthermore, as illustrated in dotted line in Figure 2, mechanical drive or an electrical signal can be derived by a unit 18 from the steering mechanism of the vehicle and applied to the unit 15 to compensate for road curvature, in beam angle.It may be found desirable to arrange that the output from the unit 18 is effective for adjustment of beam angle only when the speed of the vehicle is above some threshold value consistent with motorway driving and the steering movement is of a small amount consistent with the gentle curves experienced on motorways.

Although the system described above involves the use of visible light, the beams transmitted may instead be of infra-red light. In this case the reflector 1 may be replaced by a lighting unit that is responsive to the incidence of the beams to transmit back visible light of a colour appropriate to the zone or zones of such incidence. On the other hand, it may be arranged that infra-red light is transmitted back and that this when received by the following vehicle, actuates an indicator and/or, if appropriate, triggers an alarm. The transmitted infra-red beams may be coded so that it is only reception of the coded beams that causes the lighting unit to respond. Similarly, where infra-red beams are transmitted back, these may also be coded to avoid interference between systems, and signify which of the three situations, safe, unsafe and dangerous applies.

In addition, or alternatively, the lighting unit may include electronic logic circuits (in the form, for example, of gates) for inhibiting the return transmission where the incident beams are not received symmetrically by the unit and the degree of asymmetry exceeds a set value; departure from symmetry in this respect arises, for example, where the following vehicle is overtaking.

Claims

Claims:

1. A vehicle safety system for assisting in the maintenance of safe vehicle-to-vehicle separation, including means for transmitting beams of light forwardly from a vehicle, and means for varying the angular directions of the beams according to vehicle speed so that the points of incidence of the beams on a vehicle ahead are dependent upon both said vehicle speed and the vehicle-to-vehicle separation.

2. A system according to Claim 1 wherein the vehicle ahead carries means for transmitting back one or more signals dependent upon the spacing from one another on the vehicle ahead, of the points of incidence of the light beams.

3. A system according to Claim 2 wherein said means is reflector means for reflecting back light from the incident beams.

4. A system according to Claim 3 wherein the transmitted beams are beams of visible light and the reflector means is divided into zones for providing one or another of at least two different visual indications according to the locations of the points of incidence of the light beams thereon.

5. A system according to Claim 4 wherein the reflector means is an elongate retro-reflective reflector having a central red zone, amber zones flanking the central zone and outer, green zones flanking the amber zones.

6. A system according to any one of Claims 1 to 3 wherein the transmitted beams are beams of infra-red light.

7. A system according to any one of Claim 1 to 6 including means for varying the angular directions of the beams in dependence upon steering movements of the vehicle from which they are transmitted.

8. A method for assisting in the maintenance of safe separation between two vehicles travelling one following the other, wherein beams of light are transmitted forwardly from the following vehicle to be incident on the vehicle ahead, and the angular directions of the transmitted beams are varied according to the speed of the following vehicle so that their points of incidence on the vehicle ahead are dependent upon both the speed of the following vehicle and its separation from the vehicle ahead.

9. A method according to Claim 8 wherein one or more signals dependent on the spacing of the points of incidence from one another on the vehicle ahead, are transmitted from the vehicle ahead to the following vehicle.

10. A method according to Claim 9 wherein the one or more signals are one or more visible-light signals reflected from the incident beams of light, and are of a colour dependent on the spacing of the points of incidence from one another.

11. A method according to Claim 8 or Claim 9 wherein the transmitted beams are of infra-red light.

12. A method according to any one of Claims 8 to 10 wherein the angular directions of the beams are varied in dependence upon steering movements of the following vehicle.

13. A method for assisting in the maintenance of safe separation between two vehicles travelling one behind the other, substantially as hereinbefore described with reference to the accompanying drawing.

14. A system for assisting in the maintenance of safe separation between two vehicles travelling one behind the other, substantially as hereinbefore described with reference to the accompanying drawing.