GB2414588A

GB2414588A - Device for warning following traffic of a vehicle ahead.

Info

Publication number: GB2414588A
Application number: GB0411710A
Authority: GB
Inventors: Charles Alasdair Fairbairn
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-05-26
Filing date: 2004-05-26
Publication date: 2005-11-30
Also published as: WO2005116953A1; GB0411710D0

Abstract

An indicator unit is arranged to sense the passage of a vehicle and provide a visual warning indication for a predetermined time to following vehicles. The unit maybe in the form of an intelligent road stud 12 or a cats' eye. The unit may comprise a sensor (S) to trigger the visual warning indications. The visual warning indication may take the form of a lit red light (R) for a first predetermined period (Fig 3(a)), followed by a lit yellow light (Y) for a second period (Fig 3(b)) and finally a lit green light (G) which is the default mode. The lighting of the units may allow a sufficient gap to be maintained between two vehicles. The unit may be connected to other units and in one embodiment linked to a central control which can selectively adjust the predetermined time periods. The central controller may also include means to determine traffic density.

Description

Road Traffic Control Arrangements The present invention relates to

arrangements for road traffic control and in particular for controlling traffic densities in road networks.

Known traffic control arrangements rely typically on traffic lights, road tolls, physical constrictions or road closures. These measures do not, however, achieve efficient use of road networks. Measures are also known to assist drivers in maintaining a minimum distance between successive vehicles, but these measures are generally of limited use.

I have now devised arrangements which address these problems and so improve the efficiency of road network usage.

In accordance with the present invention as seen from one aspect, there is provided an indicator unit arranged to sense the passage of a vehicle along a road or carriageway and, in response thereto, to provide, for a predetermined time period, a visual warning indication for any following vehicle.

Preferably a series of such indicator units are disposed at intervals along a section of road or carriageway.

Preferably the units are in the form of road studs which are embedded in the road or carriageway, preferably along the centre of the road or carriageway so that the wheels on the opposite side of each vehicle pass either side of the road stud indicator unit.

As a vehicle passes each indicator unit, the indicator unit senses the vehicle and is triggered to provide its visual warning indication: the following vehicle should maintain a sufficient gap, between itself and the vehicle in front of it, such that it does not reach or pass that indicator unit until its visual warning indication has been switched off. For example, the visual warning indication may be provided by a red indicator light of the indicator unit, or the visual warning indication may be provided by a red indicator light for a first predetermined time period followed by an amber indicator light for a second predetermined period of time. At the termination of the visual warning indication, the indicator unit may provide a visual confirmatory or approval indication, preferably by a green indicator light.

Preferably the series of indicator units of a road or carriageway section are linked to a central controller which is able to adjust the duration of the visual warning indication given by the respective indicator units, in order to thereby control the density of traffic following along that section of road or carriageway. A particular use of this facility is for controlling the traffic density on two roads prior to these merging, or on two carriageways ahead of a closure on one of them: the central controller can extend the duration of the visual warning indications given by the indicator unit on the two roads or carriageways, so reducing the respective traffic densities and enabling the two lines of traffic to merge into a single line of acceptable traffic density. In the sections of roads or carriageways leading up to the point of merging (or other constriction), the visual warning indications of the successive indicator units are preferably increased in a progressive manner.

The central controller is arranged to determine the actual traffic density, in the or each section of road under its supervision, by responding to the vehicle sensor of one or more of the indicator units in that section, to count the number of vehicles passing in a predetermined time period.

Also in accordance with the present invention, as seen from a second aspect, there is provided a traffic control system which comprises a plurality of indicator units for positioning at intervals along a section of road or carriageway, each indicator unit being arranged to sense the passage of a vehicle along the road or carriageway and to provide, in response thereto and for a predetermined period of time, a visual warning indication for any following vehicle.

Although a visual warning is triggered, it is envisaged that the visual warning can be combined with other types of warnings, for example an audible warning. Having an extra warning system could act as a back up system for example in foggy conditions.

Further, the indicator units may provide a non-visual warning indicator, preferably the indicator units include a control which can transmit signals that are received by the vehicle-management system of a passing vehicle and their signals can be used to control the auto-cruise on vehicles having such equipment.

An embodiment of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which: Figure 1 is a front view of an indicator unit in the form of a road stud unit, for use in a traffic control system in accordance with the present invention; Figure 2 is a top view of the road stud unit shown in Figure 1; and Figure 3 is a diagram for use in explaining the operation of the traffic control system.

Referring to Figure 1 and 2 of the drawings, there is shown an indicator unit in the form of a road stud unit which comprises a base 10 for embedding in the road surface, and a flat-top housing 12 projecting from the base 10. On one face, the housing 10 is provided with a vehicle sensor S and a set of three indicator lights, consisting of a red light R. an amber light Y and a green light G. An electronic control circuit (not shown) is enclosed within the housing 10 and is arranged to respond to the sensor S and control the indicator lights R,Y,G.

In the road traffic control system of the present invention, a series of such road stud units are installed at regular intervals along a carriageway with the sensor S and indicator lights R,Y,G facing the oncoming traffic. Preferably the road stud units are positioned in the centre of the carriageway so that the wheels on the opposite sides of vehicles using the carriageway will run either side of each road stud unit. The electronic control circuits of the stud units are coupled e.g. by cabling to a central controller, which is able to alter the operating cycles of the respective road stud units.

Referring to Figure 3 of the drawings, each road stud unit is arranged to operate as follows. As a vehicle A passes the road stud unit, at (a) in Figure 3, its sensor S detects the presence of this vehicle and the electronic control circuit within the road stud unit responds to this to light the red indicator light R. This red indicator light remains lit for a predetermined period of time, say 2 seconds, before the electronic control circuit switches it off and instead switches on the amber indicator light Y. as at (b) in Figure 3.

The amber light Y remains lit for another predetermined period of time, say 1 second, before the electronic control circuit of the road stud unit switches it off and instead switches on the green indicator light G. as at (c) in Figure 3.

The following vehicle B should not reach the road stud unit whilst either its red or amber indicator lights are lit, but only once its green indicator light has been switched on.

The same sequence of operation takes place at each of the successive road stud units which the leading vehicle A passes. The following vehicle B should keep a sufficient distance between it and the leading vehicle A to ensure that the successive road stud units have their green indicator lights switched on as it passes them: if the following vehicle B should pass any road stud unit whilst that unit has its amber light Y or its red light R lit, then the driver of vehicle B should slow down in order to increase the gap between that vehicle and the vehicle ahead.

It will be appreciated that as each vehicle passes each road stud unit, it will trigger an operating cycle of that unit as described above, to provide a sequence of illuminated indicator lights for the benefit of the next vehicle behind.

The road stud units are linked to a central controller, which is able to control the traffic density on each selected section of carriageway. Thus, the central controller is arranged to respond to the vehicle sensor S of one or more road stud units in each section of carriageway, to determine the average number of vehicles passing per unit of time. The central controller may then control the electronic control circuits of the road stud units in that section of carriageway, in order to alter the cycle time of each road stud unit, i.e. the time period between the detection or passage of a vehicle and the switching on of its green indicator light.

The ability to control traffic density is particularly useful on sections of carriageway approaching a constriction, for example where two roads merge or where a carriageway is closed and therefore the traffic of two carriageways is required to merge onto one. In such circumstances, the central controller may adjust the operating cycles of the road stud units on the road or carriageway sections approaching the constriction, in order to lengthen the gaps between successive vehicles and correspondingly reduce the traffic density, so that the two lines of traffic can merge into one line of acceptable traffic density.

It will be noted that, in the road stud shown in the drawings, a second sensor S' and a second set of indicator lights R',Y'G' are provided on the face opposite the first sensor S and first set of indicator lights R, Y,G. Where the road stud unit is positioned in the centre of a carriageway, this arrangement enables the second sensor S' and associated indicator lights R', Y',G' to be used when, for any reason, the carriageway is used for a contraflow of traffic. Instead, the road stud unit may be used on a two-way road and positioned along the centre of this road, the sensors and indicator lights on the opposite sides of the unit being used to control the traffic on the respective sides of the road.

Although the invention has been described with respect to indicators in the form of road studs; it is envisaged that indicator units may be provided on bridges or gantries or possibly on road signs so that a driver can have the best opportunity of seeing the visual warnings. It is also envisaged that a combination of indicator units, for example on gantries and in road studs can be used, for example where there is a particularly heavy traffic flow or where there are complicated road networks.

The road traffic control system which has been described may be used in conjunction with any suitable measures for enforcing drivers to take proper account of the visual warning indications given by the successive road stud or other indicator units, or to penalise those drivers who do not.

Claims

Claims 1. An indicator unit arranged to sense the passage of a vehicle

along a road or carriageway and, in response to sensing passage of said vehicle, to provide, for a predetermined time period, a visual warning indication for any following vehicle.
2. An indicator unit according to claim 1 provided as a road stud which is embedded in the road or carriageway.
3. An indicator unit according to claim 1 or claim 2 including a sensor to sense the vehicle and trigger said indicator unit to provide its visual warning indication.
4. An indicator unit according to claim 3 including a control to prevent the indicator unit from switching to an indication showing that a vehicle can proceed until a predetermined period has elapsed from when a car passed over said unit.
5. An indicator unit according to any preceding claims wherein the visual warning indication is provided by a red indicator light.
6. An indicator unit according to any of claims 1 to 4, wherein the visual warning indicator is provided by a red indicator light for a first predetermined time period followed by an amber indicator light for a second predetermined period of time.
7. An indicator unit according to any preceding claim wherein the visual warning indicator further includes a green light providing a default mode which indicates that vehicles can proceed.
8. An indicator unit according to any preceding claim wherein a visual confirmatory indication is operated to indicate to a following vehicle that there is a sufficient gap between itself and a preceding vehicle.
9. An indicator unit according to any preceding claim in combination with a series of other indicator units.
10. An indicator arrangement comprising a series of indicator units according to any preceding claims.
11. An indicator arrangement according to claim 10 wherein the series of indicator units are linked to a central controller which can selectively adjust the duration of the visual warning indication given by respective indicator unit.
12. An indicator arrangement according to claim 10 or claim wherein the central controller includes means to determine traffic density at a road section under the supervision of the central controller by responding to the vehicle sensor of one or more indicator units in the road section to count the number of vehicles passing in a predetermined time period.
13. An indicator arrangement according to any of claims 10 to 12, wherein the arrangement is positioned at a road junction whereby the central controller can monitor traffic density and adjust traffic flow at said junction in accordance with traffic density.
14. A traffic control system comprising of plurality of indicator units according to any preceding claims positioned at intervals along a section of road or dual carriageway, each indicator unit being arranged to sense the passage of a vehicle along the road or dual carriageway and to provide in response thereto and for a period of time, a visual warning indication for following vehicles.
15. A traffic control system according to claim 14 wherein in addition to a visual warning, an audible warning is provided.
16. A traffic control system according to claim 14 or claim wherein signals are transmitted from indicator units under the control of the traffic system to a vehicle management system of passing vehicle.
17. A traffic control system according to claim 16 wherein the signals are in cooperation with the auto cruise on vehicles having such equipment.
18. A road section incorporating one or more indicator units or arrangements according to any of claims 1 to 13.
19. An indicator unit as substantially described herein with reference to and illustrated in the accompanying figures.
20. A traffic control system as substantially described herein with reference to and as illustrated in the accompanying figures.