Background of the Invention A highway transmits vehicular traffic as plural discrete (but often almost contiguous) advancing highway traffic capsules each of which comprises one or more vehicles which remain relatively static within the respective advancing traffic capsules as the latter move along the highway. Efficient advancement of a highway traffic capsule, in the sense of maximum safe vehicle volume passage per unit time, requires a balance between vehicle count in the capsule and the speed with which the capsule advances. Efficient traffic flow along a highway requires this balance to be achieved for all traffic capsules on the highway. Mathematical models (often utilizing chaos theory) abound to try to explain how traffic flows along a highway, what causes traffic flow to become impeded, and how to try to maximize traffic flow based on prevailing conditions.

In almost all countries, vehicles are largely driven by discretionary driving with enforcement against unacceptable forms of discretionary driving applied punitively as a deterrent which discourages, with varying degrees of effectiveness, only those practices which are considered a threat to highway safety. Advancement of traffic capsules along the highway in real conditions differs greatly from theoretical model advancement because of the wide freedom of choice which can be exercised by the drivers of different vehicles in practising discretionary driving (regardless of whether choices are exercised on the basis of considered responses to perceived or real driving conditions or on the basis of random discretionary choice dependent upon mood, personal

requirements and driver inter-relationships). Vehicle count in a highway capsule, for example, depends on such factors as driver perceptions of safe inter-vehicle distance, visibility, traffic volume pressure and individual speed requirements for the journeys in which individual vehicles and their drivers are engaged. The speed of advancement of a highway capsule is dependent on similar factors, and the two are obviously inter-dependent.

Discretionary driving leads to the presence on a highway of a complex array of different vehicle travel characteristics each resulting from a combination of individual driver attitudes and the influence on them of other driver attitudes and real conditions. That array produces the divergence between real traffic flow and flow which can be predicted by a model, even a relatively sophisticated one.

The array of different vehicle travel characteristics is also responsible for the capsular configuration of highway traffic. For example, a lead vehicle of a capsule on a highway travels at a speed and in an overall manner decided by the driver of that lead vehicle exercising freedom of choice on the basis of considered responses to perceived or real driving conditions and/or on the basis of random non-rational discretionary choice. That vehicle obliges all common lane following vehicles to travel in a manner influenced by the lead vehicle, in particular with respect to speed of travel, with the result that the following vehicles form, together with the lead vehicle, a traffic capsule which advances along the highway but in which the individual vehicles are essentially in stasis with respect to the capsule. Ahead of the capsule there may be a plurality of other vehicles which form a separate traffic capsule whose travel characteristics are determined by its own lead vehicle. The latter capsule should theoretically merge with the following capsule in due course if the following capsule is advancing at a higher speed. In the alternative, with the most advanced capsule advancing at a greater speed, the inter-capsule spacing will increase so that the two capsules increasingly separate one from the other.

Capsules remain intact by acceptance of lead vehicle conduct by following vehicles, either voluntary or compelled by specific highway conditions.

The presence on a highway of the complex array of different vehicle travel characteristics mentioned above is most noticeable on principal routes where space (e. g. multiple lanes), high speed limits and multiple carriageways which eliminate contra flow conditions, accommodate widely ranging exercise of choice in discretionary driving.

The availability of choice to vehicle drivers engenders a number of serious problems which in many cases are as apposite to increasing highway inefficiency as the increasing numbers of vehicles licensed to use the highways.

UK motorways (and the broadly similar roads referred to by local nomenclature in other countries) and other principal traffic routes experience a number of sometimes remarkable problems engendered by exercise of choice by vehicle drivers. For example : - 1. Spectacles, such as collision spectacles or even construction/repair spectacles, in one carriageway usually act as a virtual traffic flow constriction and give rise to slowing of traffic in an adjacent carriageway to enable the drivers of the slowing vehicles to observe the spectacle. Slowing can be catastrophic causing multiple vehicle collisions in the carriageway experiencing slow-down. In any event, the deceleration of vehicles generates a deceleration wave as successive vehicles respond to reductions in inter-vehicle distances.

Vehicles close in sequence to the lead vehicles may decelerate in a controlled fashion, possibly aided by an alert given by evidence in the adjacent carriageway of the spectacle itself. As driver alertness and vehicle distances vary from one driver/vehicle to another, the highway will inevitably experience the comparatively precipitous deceleration of one or more vehicles, and this produces a tail-back envelope of similarly precipitous decelerating vehicles many of which will decelerate to a speed substantially slower than the lead vehicles with some coming to a standstill. Slower speed conditions of the highway may render it incapable of absorbing extant traffic volume pressures, highway capsules in the tail emanating from the lead vehicles being forced to stasis as they cannot be admitted to more forward parts of the highway.

Separate capsules tend to merge on slow-down, reforming with different

characteristics and composition and usually again undergoing merger until the virtual construction has been cleared.

2. The majority of drivers seek speed in the belief that this will result in efficiency of travel. However, data shows that safe vehicle distances at speed mean that a highway capsule progressing at speed s1 and containing n1 vehicles safely distanced at safe distance d1 advances more vehicles per unit time than a capsule progressing at a higher speed s2 and containing a smaller number of vehicles n2 safely distanced at larger safe distance d2.

3. Many drivers engage in multiple lane changing upon a perception that different lanes in congested conditions advance at different speeds. However, tests show that multiple lane changing achieves little for the vehicle concerned, accelerates driver fatigue and can slow other vehicles.

4. A lead vehicle in a highway capsule dictates the speed of the capsule.

Discretionary driving can thus lead to damage to traffic flow efficiency when a vehicle maintains such a commanding position whilst at the same time advancing at a speed less than the highway conditions will permit. Such a vehicle usually characterises the capsule it leads as one which has a void of unoccupied highway beyond its head.

5. Multiple lane highways usually are configured with the intention or acceptance that different lanes will be used by vehicles of different speed.

Thus, for example, a UK motorway has in general three lanes with the outermost lane (on the right) used by relatively fast vehicles in overtaking mode.

In relatively congested conditions, such vehicles tend to occupy that lane permanently or semi-permanently in increasing numbers, encouraged by the conviction that this will result in higher average speed for the vehicles concerned, at the expense of traffic volumes in the remaining lanes, particularly the inside lane (on the left). In very many cases, transfer of vehicles to one of those two lanes would enable an increase in the discharge of traffic by the highway as a whole because the two inner lanes are otherwise operating at inefficiently low traffic density with highway traffic capsules having low vehicle

counts. This is particularly so where inner lanes are characterised by highway traffic capsules having voids of unoccupied highway beyond their heads.

6. Under jam conditions, the vehicles making up the jam and in common lane form a compacted supercapsule which is in stasis or in crawl with vehicles not in top gear. Removal of the cause of the jam releases the supercapsule which begins to decompact starting at its leading edge. Alert drivers tend rapidly to accelerate during decompaction and are commonly motivated, by a desire to compensate for the delays of the jam, to do so prematurely and excessively. Other drivers do not do so but participate with their vehicles in decompaction in a retired manner which may obstruct vehicles to their rear.

Differences in drivers attitudes in decompaction cause the fragmentation of the supercapsule to form plural separate traffic capsules in the manner referred to earlier. Under conditions of premature and/or excessive acceleration during supercapsule decompaction, inter-vehicle spacing is tolerated which ordinarily would not be accepted by drivers in exercise of discretionary driving. Indeed, driving is generally effected with a higher than usual degree of recklessness.

This, at worst predisposes the highway to collisions between vehicles which detract from highway safety and which also engender further jam-producing highway obstruction; at best, this recklessness leads to driver tensions which predisposes drivers to precipitous deceleration of one or more vehicles causing production of a tail back envelope of similarly precipitously decelerating vehicles.

Brief Summary of the Invention The present invention therefore seeks to provide a system and an apparatus for facilitating improved traffic flow along a highway.

Accordingly, in a first aspect, the invention provides an apparatus for facilitating improved traffic flow along a highway, the apparatus comprising a central processing station for receiving a plurality of information signals, each signal being indicative of actual highway travel characteristics for a vehicle on the highway, the central processing station including means for determining a model

of actual vehicle flow along the highway from the actual highway travel characteristics, means for determining a virtual model of efficient vehicle flow along the highway based on a predetermined theoretical model of traffic flow along the highway and the model of actual vehicle flow along the highway; and means for generating instructions for one or more selected vehicles on the highway to change at least one vehicular highway travel characteristic, said instructions being collectively designed to conform the model of actual vehicle flow along the highway to those of the virtual model of efficient vehicle flow along the highway.

In a preferred embodiment, the model of actual vehicle flow along the highway determines whether vehicles on the highway are within a traffic capsule and defines a model of actual traffic capsule flow for those vehicles. Preferably, the virtual model of efficient vehicle flow along the highway includes a virtual model of efficient traffic capsule flow along the highway and the instructions are generated in order to conform the model of actual traffic capsule flow along the highway to the virtual model of efficient traffic capsule flow along the highway.

Tthe virtual model of efficient traffic capsule flow along the highway is conveniently designed to maximise the quantum of traffic flow as represented by the rate of displacement forward along the highway of the traffic capsule.

In one embodiment of the invention, at least one of the information signals indicative of actual highway travel characteristics for a particular vehicle on the highway is transmitted from a highway travel characteristics detector positioned adjacent the highway.

In a preferred embodiment of the invention, at least one of the information signals indicative of actual highway travel characteristics for a particular vehicle on the highway is transmitted from that particular vehicle. Preferably, all of the information signals indicative of actual highway travel characteristics on the highway are transmitted from the respective vehicles.

The actual highway travel characteristics preferably include any one or more of the following :

the instantaneous global position of the signalling vehicle and its identity and type; a respective vehicle module length for the vehicle and a respective vehicle velocity for the same vehicle ; and information regarding the proximity of the signaling vehicle to other vehicles and/or to boundaries of the highway.

Preferably, the model of actual vehicle flow along the highway utilizes a set of highway model use values including values for respective model velocities for the vehicles and values for respective model vehicle module lengths for said vehicles to determine whether the vehicles are within a traffic capsule and to define a model of actual traffic capsule flow for those vehicles in the traffic capsule. The respective model vehicle module lengths are preferably, in each case, the sum of the length of the vehicle in question, a safe following distance for that vehicle at the vehicle velocity in relation to the vehicle which it follows and a margin for error. The respective lengths for the respective vehicles are conveniently the actual lengths for the respective vehicles and wherein respective information signals provide a code from which such length can be determined for the respective vehicle by the central processing station. The respective safe following distances for the respective vehicles at respective model vehicle velocities are preferably the actual safe following distances for the respective vehicles at respective model vehicle velocities and wherein respective information signals provide a code from which such safe following distances can be determined for the respective vehicle by the central processing station. The respective lengths for the respective vehicles are preferably nominal lengths for the respective vehicles. The respective safe following distances for the respective vehicles at respective model vehicle velocities are preferably respective nominal safe following distances for the respective vehicles at respective model vehicle velocities.

According to a second aspect, the invention provides a system for facilitating improved traffic flow along a highway, the system comprising an apparatus according to any preceding claim, for receiving at least one of the plurality of information signals, and at least one transmitter having a telecommunications

link to the apparatus, for transmitting one or more command signals including the instructions for one or more selected vehicles on the highway to change at least one vehicular highway travel characteristic, wherein the transmitter (s) is remote from the central processing station.

In one embodiment, the system further comprises at least one detector positioned adjacent the highway for detecting at least one of the highway travel characteristics for a passing vehicle and for transmitting the information signal indicative of the detected actual highway travel characteristics for the particular vehicle. Preferably, the central processing station is remote from the detector (s) and the detector transmits the information signal either directly to the apparatus, or indirectly via the particular vehicle.

The system preferably further comprises at least one indicator positioned adjacent the highway for displaying the instructions for one or more selected vehicles on the highway to change at least one vehicular highway travel characteristic, the indicator being remote from the central processing station and having a telecommunications link thereto.

A telecommunications transceiver is preferably provided in at least one of the selected vehicles for transmitting said information signal and for receiving said command signal.

In a preferred embodiment, the system further comprises at least one receiver for receiving the information signal transmitted by a vehicle, the receiver (s) is remote from the central processing station and has a telecommunications link thereto. Preferably, said receiver and said transmitter are provided by a single transceiver station.

Conveniently, there is provided a plurality of transceiver stations at spaced locations to provide suitable coverage for the highway.

Preferably, said information and command signals are transmitted using a cellular telecommunications network, although they could, alternatively, be

transmitted using a private trunked telecommunications network, or, indeed, any other suitable telecommunications link.

The instructions included in the command signals preferably include instructions to drivers of said one or more selected vehicles on the highway to change speed or traffic lane. The instructions included in the command signals are preferably displayed visually or manifested audibly within the vehicle to the respective driver.

In a third aspect, the invention provides a method for facilitating improved traffic flow along a highway, the method comprising the steps of receiving a plurality of information signals, each signal being indicative of actual highway travel characteristics for a vehicle on the highway, determining a model of actual vehicle flow along the highway from the actual highway travel characteristics, determining a virtual model of efficient vehicle flow along the highway based on a predetermined theoretical model of traffic flow along the highway and the model of actual vehicle flow along the highway, and generating instructions for one or more selected vehicles on the highway to change at least one vehicular highway travel characteristic, said instructions being collectively designed to conform the model of actual vehicle flow along the highway to those of the virtual model of efficient vehicle flow along the highway.

Preferred features of the method are described above with reference to the apparatus and system according to the invention.

In a fourth aspect, the invention provides a method of highway traffic flow control which method comprises receiving at a receiving station from an or each vehicle in a traffic capsule consisting of vehicles travelling in a direction along a selected length of a lane of a carriageway, respective signals which signify actual highway travel characteristics for the signalling vehicle in use of the highway, comparing the highway travel characteristics of the capsule with a highway use virtual model for said capsule, and signalling one or more selected vehicles in said capsule with a command which signifies a change in at least one vehicular highway travel characteristic, said commands collectively

designed to conform the actual highway travel characteristics for the capsule to those of the virtual model.

Preferably, said respective signals from said vehicles in said traffic capsule signify the instantaneous global position of the signalling vehicle and its identity and type. The respective signals from said vehicles in said traffic capsule preferably signify respective vehicle module lengths for the vehicles therein and respective vehicle velocities for the same vehicles, and the highway use model preferably comprises a set of highway model use values including values for respective model velocities for the vehicles in the traffic capsule and values for respective model vehicle module lengths for said vehicles.

In a preferred embodiment, the model is designed to maximise the quantum of traffic flow as represented by the rate of displacement forward along the road of the highway traffic capsule. Preferably, the respective model vehicle module lengths are in each case the sum of the length of the vehicle in question, the safe following distance for that vehicle at vehicle velocity in relation to the vehicle which it follows and a margin for error.

Preferably, the respective lengths for the respective vehicles are the actual lengths for the respective vehicles and wherein respective vehicle signals received at said receiving station provide a code from which such length can be determined for the respective vehicle by means of the receiving station.

The respective safe following distances for the respective vehicles at respective model vehicle velocities are preferably the actual safe following distances for the respective vehicles at respective model vehicle velocities and the respective vehicle signals received at said receiving station preferably provide a code from which such safe following distances can be determined for the respective vehicle by means of the receiving station.

The respective lengths for the respective vehicles are preferably nominal lengths for the respective vehicles and the respective safe following distances for the respective vehicles at respective model vehicle velocities are preferably

respective nominal safe following distances for the respective vehicles at respective model vehicle velocities.

According to a fifth aspect, the invention provides a method of traffic control comprising signalling vehicles on a carriageway to signify to drivers thereof to change speed or traffic lane in order to conform the use of the carriageway to a virtual model of an ideal pattern of use of the carriageway by the vehicles using it, the vehicles signalling a base station with signals signifying the characteristics of their actual use of the carriageway and the base station comparing actual use by the traffic with the virtual model before signalling the vehicle (s), signals received by the vehicle (s) causing a representation of the commands they signify to be displayed visually or manifested audibly to the driver.

According to a sixth aspect, the invention provides a system for facilitating improved traffic flow along a highway, the system comprising a plurality of receiver stations for receiving information signals, each signal being indicative of actual highway travel characteristics for a vehicle on the highway, and an apparatus located remotely from at least one of the receiving stations, the apparatus including means for generating instructions for one or more selected vehicles on the highway to change at least one vehicular highway travel characteristic, said instructions being collectively designed to conform actual vehicle flow along the highway to a virtual model of efficient vehicle flow along the highway.

According to a seventh aspect, the invention provides a system for facilitating improved traffic flow along a highway, the system comprising a plurality of transmitter stations for transmitting command signals, each signal including instructions for one or more selected vehicles on the highway to change at least one vehicular highway travel, and an apparatus located remotely from at least one of the transmitter stations, the apparatus including means for generating the instructions for one or more selected vehicles on the highway to change at least one vehicular highway travel characteristic, said instructions being collectively designed to conform actual vehicle flow along the highway to a virtual model of efficient vehicle flow along the highway.

According to an eight aspect, the invention provides an apparatus for facilitating improved traffic flow along a highway, the apparatus comprising a central processing station for receiving information signals, each signal being indicative of actual highway travel characteristics for a vehicle on the highway, and a memory device located remotely from the central processing station and having stored therein a theoretical model of vehicle flow along the highway, the central processing station including means for generating instructions for one or more selected vehicles on the highway to change at least one vehicular highway travel characteristic, said instructions being collectively designed to conform actual vehicle flow along the highway to the theoretical model of vehicle flow along the highway.

In an alternative embodiment, the memory is integral with the central processing station.

Preferably, the apparatus can be the type of apparatus described above.

In a still further aspect off the invention, there is provided a method of traffic flow control for a single or multiple lane carriageway of a single or multiple carriageway highway, particularly but not exclusively for a multiple lane carriageway of a multiple carriageway highway, which method comprises (i) defining within a computer a virtual traffic highway use model for a dynamic highway traffic capsule consisting of the vehicles travelling on a selected portion of the length of a lane of the highway, said model comprising a set of highway model use values (eg for individual vehicles or the capsule or sub-capsules within it) comprising, for example, values for dynamic parameter (s) such as values for respective model velocities for the vehicles in the highway capsule and/or values for respective model vehicle module lengths for the same vehicles (the model may also define such highway use values as vehicle lighting, constancy of speed for individual vehicles, acceleration or deceleration for the capsule or for one or more vehicles therein, and position such as constancy of position of vehicles in a lane), (ii) receiving (eg by a signal such as a cellular telephone signal) for (eg from) each of the vehicles in the capsule, real

instantaneous highway use values counterpart to the highway model use values of the virtual model, and (iii) signalling (eg by a cellular telephone signal) each of the signalling vehicles, or one or more (eg each or only one) of selected signalling vehicles, with a command which signifies change to one or more real vehicle highway use values therefor, said commands collectively designed to increase conformity between real traffic highway use for the dynamic traffic capsule and the virtual traffic highway use model and in general signals received by vehicles causing a representation of the commands they signify to be manifested visually or audibly to the driver to which they are addressed.

Brief Description of the Drawings One embodiment of the invention will now be more fully described, by way of example, with reference to the drawing which shows a schematic diagram of a system according to one embodiment of the present invention.

Detailed Description of the Drawings Thus, there is shown in the drawing a multiple lane carriageway 1 of a highway (the other carriageway not being shown for simplicity), having a number of vehicles travelling along one of the lanes. As shown, the vehicles are traveling in two traffic capsules 2 and 3, a first traffic capsule 2 of which is led by a leading vehicle 4 and the second traffic capsule 3 of which includes a vehicle 5 in a moving queue of vehicles following a lead vehicle of the traffic capsule. As will be appreciated, there is a space between the two traffic capsules, which space will increase if the lead vehicle 4 of the first capsule 2 is moving faster than the lead vehicle if the second capsule 3, and which will, in time, disappear so that the two capsules merge into one, if the lead vehicle of the second capsule 3 is traveling faster than the lead vehicle 4 of the first capsule 2.

A satellite constellation is shown schematically having satellites 6, which are used for determining position of the vehicles on the highway. The satellites may form part of the so-called Global Positioning System (GPS), which is well known and will not be further described below. As is also known, it is becoming

common for vehicles to be fitted with appropriate GPS location systems so that the position of the vehicle can be established by the vehicle and either displayed to the driver thereof, or utilized by equipment in the vehicle to inform the driver of a proposed route to a desired destination.

At spaced locations, there are provided transceiver stations 7 and 8, for receiving and transmitting signals. The transceiver stations 7 and 8 may be, for example, cellular base stations, as are well known, which receiver and transmit signals from cellular telephones and other equipment utilizing the cellular network, which may be a GSM network. In particular, the transceiver stations 7 and 8 can be used to receive and transmit signals from and to equipment in one or more of the vehicles on the highway. It is, of course, common for vehicles to have mobile or cellular telephones, which communicate with such transceiver stations to allow a person in the vehicle to carry on a telephone conversation while the vehicle is moving. However, the transceiver stations can also be used to provide communication with appropriate equipment on the vehicle, as will be further described below.

Each of the transceiver stations 7 and 8 have a telecommunications link to a central processing station 9 located remotely from the transceiver stations 7 and 8. The central processing station may be co-located at, or even form part of, a centralized control station controlling the cellular network, but could be located elsewhere. Although the telecommunications links from the transceiver stations 7 and 8 are shown as fixed links, such a wireline, or optical fibre line links, they could alternatively be wireless links, as appropriate. For example, if the transceiver stations formed part of a satellite cellular system, the telecommunications links would clearly be wireless.

In order to facilitate improvement in traffic flow, one or more of the vehicles are provided with equipment that includes an ID memory, a GPS receiver (or similar device for determining global position of the so-equipped vehicle), a speedometer, a cellular transceiver and a command display. Although, for optimum facilitation of traffic flow, it is preferable for all vehicles to be so equipped, as will be described below, some improvement in traffic flow can still

be obtained even if only some vehicles are so equipped. The equipment also desirably includes proximity sensors for determining the distance forwards and, possible also, backwards to an adjacent vehicle, and may also include sideways sensors to determine the distance to an edge of the highway or another vehicle traveling in parallel with the particular vehicle. Thus, the vehicle can transmit actual highway travel characteristics, including its position, as determined by the GPS receiver, its speed, and its ID. ID for a particular vehicle includes its type (in sufficient detail to enable regulatory speed limitations applicable to the vehicle and vehicle acceleration/speed capacity to be recognised), vehicle length (from which vehicle module length can be calculated) and registration details (so that non-compliance with commands can be dealt with by legal remedies, if required). Position can include distance relative to vehicle ahead and highway lane identity based on information form the proximity sensors.

The actual highway travel characteristics are received by the appropriate transceiver station 7 or 8, and passed on to the central processing station 9.

The central processing station 9 includes a computer (processor) 10 that receives the actual highway travel characteristics from vehicles on the highway and determines a model of actual vehicle flow along the highway from the received actual highway travel characteristics. The central processing station 9 determines whether and which vehicles on the highway are within a traffic capsule and defines a model of actual traffic capsule flow for those vehicles, which forms part of the model of actual vehicle flow. A memory 11, which is either within the central processing station 9 or remote therefrom and linked thereto by a telecommunications link, has stored therein a theoretical model of vehicle flow, which has been predetermined as a general theoretical model of vehicle flow for most general circumstances for that highway or portion of highway. The central processing station 9 can also be linked, via a suitable telecommunications link 12 to one or more other central processing stations (not shown) or other stations (also not shown) to receive appropriate information regarding traffic and other conditions either within the area covered by the central processing station 9, or outside that area. For example, conditions within the area may include weather conditions, occurrence of spectacles, public events, etc. Similarly, conditions outside the area that may affect traffic flow

within the area include occurrence of spectacles, public events and actual traffic flow outside the area. The central processing station 9 then develops a virtual model of efficient vehicle flow for the area based on the model of actual vehicle flow along the highway, the general theoretical model of vehicle flow and the information received regarding traffic and other conditions, both within and outside the area. This virtual model of efficient vehicle flow for the area will of course be continuously adapted as the model of actual vehicle flow and the traffic and other conditions change.

The central processing station 9 then compares the model of actual vehicle flow along the highway with the developed virtual model of efficient vehicle flow along the highway and determines how actual highway travel characteristics need to change in order to converge the two models. The central processing station 9 then selects one or more vehicles whose actual highway travel characteristics need to change and generates instructions for those vehicles to direct drivers to change particular actual highway travel characteristics e. g. to change speed or lane, the instructions collectively being designed to increase conformity between the model of actual vehicle flow along the highway and the virtual model of efficient vehicle flow.

The virtual model of efficient vehicle flow can include a set of highway virtual model use values (e. g. for individual vehicles or the capsule or sub-capsules within it) comprising, for example, values for dynamic parameter (s) such as values for respective model velocities for the vehicles in the highway capsule and/or values for respective model vehicle module lengths for the same vehicles (the model may also define such highway use values as vehicle lighting, constancy of speed for individual vehicles, acceleration or deceleration for the capsule or for one or more vehicles therein, and position such as constancy of position of vehicles in a lane).

The instructions generated by the central processing station 9 are then included in command signals sent to an appropriate transceiver station or stations for transmission to the selected vehicle. The command signal received by a vehicle

is then processed in the vehicle so that a representation of the instructions is manifested visually or audibly to the driver to which they are addressed.

In the case of a multiple lane carriageway, it will be appreciate that a virtual model of efficient vehicle flow for a length of the carriageway of plural lanes constituting part thereof (e. g. the outer two lanes of a three-or other multiple- lane carriageway) defines a virtual model of efficient vehicle flow for a capsule in any particular lane. Such a virtual model of efficient vehicle flow for a length of a carriageway or of a length of plural lanes constituting part of the lane composition across the lateral extent of the carriageway expresses a model distribution of vehicles amongst the lanes.

It should be noted that individual vehicles travel at the tail of their own respective vehicle modules, each such vehicle module representing in its length the sum of the vehicle length and the safe stopping distance which must be provided between the vehicle, at its particular speed, and a vehicle ahead.

The command signals received at a vehicle conveniently cause actuation of a visual display conveying to the driver a command as to the action a driver should take. Simple displayed commands such as CHANGE LANE, INCREASE SPEED or DECREASE SPEED may be adequate but in practice a command screen will be provided so that a visual representation of DECREASE SPEED or INCREASE SPEED command (which may be in the form of a coloured lamp output, green perhaps indicating increase and red representing decrease) may be accompanied by a visual data display indicating actual commanded speed.

However, simplicity of command interpretation is crucial in order to minimise driver distraction. A suitable command screen may be a liquid crystal display device, which may be monochrome or polychromatic, and may be of any suitable size or shape, preferably rectangular. In order not to distract the driver the display device is conveniently mounted on a dashboard of the vehicle, preferably on the driver's left side in a right hand drive vehicle and vice versa.

The display device, can, of course, alternatively be, a so-called heads-up display, so that the information is displayed to the driver on the windscreen

through which the driver is looking at the highway ahead. Such displays are well known in the art.

Thus, in one embodiment, the vehicle is provided with an apparatus comprising a telecommunications transceiver, an interface device coupled to the transceiver and having a first input for coupling to a speedometer of the vehicle and a second input for receiving vehicle ID information, a display device coupled to the interface device, and a GPS receiver coupled to the interface device, the interface device being capable of receiving position information indicative of the location of the vehicle from the GPS receiver, vehicle speed information from the speedometer, and vehicle ID information and for controlling the transceiver to transmit an information signal including information indicative of the vehicle ID, the vehicle speed, and the vehicle location, wherein the transceiver is capable of receiving instructions for the vehicle to change at least one vehicular highway travel characteristic, the instructions being displayed by the interface device on said display device for a driver of the vehicle.

An audible signal (e. g. a tone or voice signal) may be desirable as a command is received in order to alert the driver to the command and thus the apparatus provided on-board for command visual display will conveniently include or be associated with sound generation apparatus such as a tone generator or an audio transducer such as one reproducing voice. The sound generation apparatus may combine the alert signal output with white noise output as alert signals so accompanied have been found to enable the human ear immediately to identify source location so that the driver's eyes are directed to the visual display with maximum speed and minimum mental effort, thus maximising response, minimising driver fatigue and guarding against the risk of demotivating drivers against responsiveness. Further details regarding the combination of alert signals and white noise can be obtained from Sound Alert Technology Ltd and from patent specifications in relation to which that company is a patent applicant.

Vehicle module sizes are required to be disproportionately large at higher vehicle speeds such that vehicle flow rate observing minimum vehicle module lengths is higher as vehicle speeds decrease.

The distances shown in the table below are the shortest stopping distances which are shown in the UK Highway Code for particular vehicle speeds. They assume a nominal automobile (and thus do not distinguish between different makes of vehicle) which is a car in good condition and further assume a dry road (where the conditions are wet, the shortest stopping distances will be larger) : - Overall Thinking Braking Stopping M. P. H. Distance Distance Distance (feet) (feet) (feet) f i i- '40'40'80'120 [40-| 40 01. L v '60'60'180'240 j 40 40 80 120 , 50 50 125 . 1.. 75........ , 60 __. _. . : 6 _. _.. _... 1 18°.. .".", _ 240H. w = 70 _ ..-245 '... _,, __ _ !'80'80 !'320'400 1 70 1 70 1 245 | 315 iL° L° l 320 _XL°° _ _ It will be understood from the above that in practice, when observing safe inter- vehicular spacing, vehicle flow rate past a point decreases as vehicle speed increases. For example, at 60mph, capsule speed is twice that 30mph but vehicle module length is increased to 240/75 with the result that the capsule progresses at greater speed but its density is so reduced that the overall flow- past of vehicles is significantly less.

It will, of course, be clear that, in the case of a highway enjoying low traffic concentration, the objective of achieving individual driver speed aspirations, within controls, is feasible at the expense of traffic flow rate whereas, under high traffic load conditions the objective must be to maximise flow since inadequate overall flow will inevitably in such conditions lead to the congestion which is characteristic of an available flow : demanded flow discrepancy.

Accordingly, in low density traffic conditions, the virtual model of efficient vehicle flow may, and usually will, be one designed to accept high speed since overall flow rate is less of a concern than it is in high density conditions. The virtual model of efficient vehicle flow in such a case will thus, in practice, often be one in which all the component vehicles are travelling forward at maximum lawful speed with the inter-vehicular spaces the minimum safe distances for that speed. The virtual model capsule as an ideal, however is a capsule designed to maximise the quantum of traffic flow as represented by the rate of displacement forward along the road of the dynamic traffic capsule.

Alternative sub-ideal model capsules will in practice be designed for particular purposes and particular situations. For example, a capsule may be travelling at a speed of 50mph determined by a lead vehicle whose driver has determined to travel at that speed, perhaps because it suits his driving style or journey requirements, the inter-vehicular spacing within the capsule representing safe distances in case one or more of the vehicles should need to stop (or rapidly slow down). Removal of the lead vehicle from the head of the capsule permits the second vehicle to increase speed, say to 70mph. Its doing so results in the second vehicle pulling away from the rest of the capsule. Having done so, the spacing between the second vehicle and the third vehicle will have increased eventually to one permitting the third vehicle to match the new higher speed of the second vehicle ; similar results are achievable by withdrawing vehicles from intermediate positions in the capsule. In this way, individual vehicle higher speed aspirations may be accommodated, provided traffic density allows it, so that individual vehicles may travel faster. The central processing station 9 will have, in such circumstances, information indicating that traffic density will permit

such an accommodation of individual driver speed aspirations, such information having been determined by the volume of individual vehicles on the highway, or in particular lanes thereof, reporting their ID's and travel characteristics. Having such information, the central processing station determines a suitable virtual model for the capsule concerned which accommodates such speed aspirations and commands the vehicles in the capsule to change travel characteristics so as to conform with the virtual model (although, of course, conformity will in practice likely at best be an approximation to the virtual model). The first command in such circumstances will, generally, be to the first vehicle to command it to pull over (and thus leave the capsule), or alternatively to command it to pull forward with increased speed so as to distance itself from the rest of the traffic capsule ; of course, the subsequent vehicles may increase speed automatically as a response to the stepwise pulling away of a forward vehicle rather than each requiring a command to do so.

Signals from capsule vehicles may include information indicating (i) vehicle type normally including speed and acceleration capability, (ii) vehicle ID usually inclusive of registration details for the purpose of applying legal remedies for non-compliance with base station commands and (iii) vehicle length.

Model capsule length is as a minimum in practice the sum of the respective lengths for the respective vehicles therein, respective safe following distances for the respective vehicles at respective model vehicle velocities (which may or may not be approximately the same) and usually also a margin for error. A real capsule compared to the virtual model may be composed of identifiable sub- capsules each of which qualifies as a capsule in its own right but is not necessarily treated as such by the central processing station. It will be appreciated that, as noted above, individual vehicles travel at the tail of their own respective vehicle modules, each such vehicles module representing in its length the sum of the vehicle length and the safe stopping distance which must be provided between the vehicle, at its particular speed, and a vehicle ahead (and usually also a margin for error, as intimated above).

The respective lengths for the respective vehicles may be nominal lengths for the respective vehicles (conforming to maximum car size), although there must be provision for identifying exceptions to a nominal length figure which covers less than all vehicle types (recognising, for example, that a truck/lorry may be very substantially longer than any car as well as having smaller stopping power in most cases). The respective safe following distances for the respective vehicles at respective model vehicle velocities are conveniently respective nominal safe following distances for the respective vehicles at respective model vehicle velocities.

The respective lengths for the respective vehicles may more appropriately be the actual lengths for the respective vehicles, respective vehicle signals received at a receiving station providing a code from which such length can be determined for the respective vehicle by means at the base station.

The respective safe following distances for the respective vehicles at respective model vehicle velocities are most conveniently the actual safe following distances for the respective vehicles at respective model vehicle velocities and respective vehicle signals received at a receiving station may conveniently provide a code from which such safe following distances can be determined for the respective vehicle by means at the receiving station.

It will readily be understood from the foregoing that increased conformity between real traffic highway use and model use requires a change in individual vehicle highway use. In the case of a first traffic capsule lagging a second traffic capsule, the lead vehicle in the first traffic capsule can be signalled to accelerate or to pull over, to the adjacent lane in case of a multiple lane signal direction carriageway or to a side-of-road parking provision in other cases.

In the case of an acceleration demand signal, or a signal having acceleration as an option for compliance, signalling to a following vehicle in the same capsule is most conveniently effected in response to increased spacing between the following vehicle and that ahead of it (eg resulting from acceleration or pulling over of the forward vehicle). Simultaneous acceleration demand signals to

vehicles in sequence may be dangerous due to different response times as between one vehicle and another, and simultaneous pull-over demand signals may similarly lead to poor highway conduct.

In high traffic load conditions for any particular lane, traffic redistribution over plural lanes may be desirable either to increase overall flow of traffic or to enable satisfaction of individual vehicle speed aspirations whilst not deleteriously affecting overall flow rate. In the latter case, it is desirable to cause redistribution out of fast lines. In such cases, redistribution can be accomplished by signals demanding lane change. Usually, such signals should be directed to selected vehicles rather than randomly. Selectivity may be on the basis of absolute position in the capsule concerned. For example, vehicles relatively forward in the capsule are vehicles whose redistribution to another lane will advantage most other vehicles in the capsule simply because a forward vehicle by definition has more following vehicles. However, in general, it appears that export of plural vehicles from selected positions in the capsule is most advantageous to produce a generally even dilution in lane traffic density.

Selection in practice will also take account of the capacity of particular locations in an adjacent importing lane to absorb exported vehicles from particular positions in the exporting lane. Of course, lane redistribution may have for its objective efficient use of lanes other than a fast (i. e. outermost) lane.

Although, in the embodiment described above, the vehicles themselves (although not necessarily all the vehicles) are provided with transceivers to transmit the information signals including the actual highway travel characteristics and to receive the command signals so as to indicate the instructions to the driver of the vehicle, it will be appreciated that not all vehicles may be so provided. In particular, older vehicles may not be retro fitted with such transceivers and the other equipment needed to provide the actual highway travel characteristics, or may be fitted with only some of the equipment and therefore cannot provide all the actual highway travel characteristics.

Therefore, a plurality of stationary detectors 13 may be provided spaced by the side of the highway 1 in order to detect at least some of the actual highway travel characteristics, such as speed, numbers and type of vehicles, including,

perhaps vehicle registration details, etc. This data is then transmitted by a telecommunication link, which may be wireline or wireless, to the central processing station 9 either directly or via the transceiver station (s) 7 and 8.

Such data can be used instead of, or to supplement, the actual highway travel characteristics received directly from vehicles fitted with the appropriate equipment. Alternatively, the detectors could, in some cases, provide all or some of the data to the vehicle being detected in order for that vehicle to transmit the data to the transceiver station (s) 7 and 8.

Similarly, a plurality of display devices 14 may be provided spaced by the side of the highway 1 in order to display the instructions to drivers of vehicles to change at least one vehicular highway travel characteristic. Although this method of displaying the instructions to drivers may not be able to discriminate between separate vehicles to a great extent, it may serve to provide instructions to a plurality of vehicles at once, and, in some circumstances, it may even be possible to provide such instructions for particular vehicles, by indicating an ID of the vehicle or driver for which a particular instruction is being displayed. The insdtructions can be transmitted to the display devices by a telecommunication link, which may be wireline or wireless, from the central processing station 9 either directly or via the transceiver station (s) 7 and 8. It will be appreciated that, although the detectors 13 and the display devices 14 are shown at different locations along the highway, they could, of course, be co-located, and could form part of the same piece of equipment.

The following Examples are intended to illustrate the invention by way of example only, the vehicle signalling equipment and computer equipment in each Example being as described above:- Example 1 A capsule A of vehicles comprising twenty five cars of various sizes and types is advancing along a lane of a three-lane carriageway at a speed of 59 mph. The capsule is lead by a car C1 (having a speed of 59 mph). The capsule occupies the outside lane of the carriageway. Beyond the head of the capsule is the tail car C2 of a further capsule B advancing at a speed of 64 mph. The position,

speed and essential ID (including type and registration details) of Car C1 has been signaled to the computer, as have the actual highway travel characteristics of car C2 and the other cars in the capsule and the computer has determined the required vehicle module lengths and the excess space if any between the vehicles in the capsule at the respective vehicle speeds. The computer has further determined that the capsule A is lagging the capsule B by 0.6 miles.

The computer signals car C1 to display a command to increase speed to a limit, which will be 70 mph in the case of UK highway law, or to pull over to the centre lane. Car C1 in fact accelerates to 63 mph and has also pulled over to the centre lane of the highway within 0.5 mile. The balance of the capsule responds by the cars that were to the rear of the car C1 immediately accelerating to a speed of 70 mph, thus conforming to a computer model for the capsule requiring it to progress at that speed. Capsule B is similarly treated to conform it to the same model. Legislative change may permit conformity with temporary models which call for a temporary speed of more than 70mph (perhaps only marginally more than 70mph) in order for Capsule A to close the gap with Capsule B to the point where the two capsules have merged to form a larger Capsule A/B (thus making more efficient use of the available highway).

Example 2 A capsule A'of vehicles has the composition of capsule A in Example 1 except that one of the vehicles is a truck T12 positioned in twelfth position in the capsule. The capsule is advancing in the outside lane of a three-lane carriageway at a speed of 53 mph. Capsule B advances away from the head vehicle in capsule A'at a speed of 64 mph. The instantaneous lag of capsule A1 to the rear of capsule B is 0.6 miles.

The lead vehicle A'in capsule A'is signalled by the computer to increase speed to a limit equal to the approximate maximum for cars on dual-carriageway roads (eg 70 mph) or to pull over. Once it has done either, the computer successively signals the following vehicles capable of the limit speed to do the same, transmitting such signals in response to a trigger operating when the distance between a signalled vehicle and the next in sequence along the travel path of

the latter reaches a predetermined threshold or when the signalled vehicle leaves the capsule by pulling over (thus creating infinite distance between the two vehicles along the travel path of the second). The vehicle A1 accelerates.

When the distance between vehicle A1 and the next following vehicle exceeds the safe following distance for the speed of the following vehicle, that following vehicle is also signalled by the computer to accelerate to the limit speed or to pull over to the centre lane. The computer continues to signal vehicles in the capsule A'in a similarly controlled fashion responsive to inter-vehicle spacing.

Truck T12 is, however, signalled to pull-over to the centre lane. Truck T12 has indicated its essential identity in its signals to the computer and the computer recognises from this information the vehicle type as indicating a vehicle which should not travel at the limit speed and thus does not signal truck T12 with a signal which allows the option of acceleration.

Example 3 Two traffic capsules A and B are travelling on a highway as noted in Example 1 but there are also Capsules C to J ahead of Capsule B forming a total of five pairs of capsules all related to one another as are Capsules A and B in Example 1 and each capsule pair being spaced from the next by 0.7 miles. The capsules travel in the outer lane of the southbound carriageway of the highway. In the northbound carriageway, an accident has occurred and the traffic there is in stasis. As Capsule J approached the virtual constriction represented by the stationary traffic in the northbound carriageway, slow-down will ordinarily begin to occur as the accident spectacle is observed by a portion of the drivers in the outer lane of the southbound carriageway. The stasis in the northbound carriageway has, however, been recognised by the computer as a result of signals received thereby (e. g. from slow vehicles in that carriageway, or from other information providers). Its response is to reconfigure the virtual models for the Capsules A to J in anticipatory manner. Because it is impossible to force drivers completely to ignore a spectacle, they cannot effectively by signalled to increase speed (or not to slow down) so that vehicle speed is at a point where observation is impractical. However, the extreme slowing down of a minority of drivers in a capsule (each of which breaks up the capsule and slows vehicles to the rear to the speed of the slow vehicle concerned) can be abated by

command by partial slowing. The drivers in Capsule J are therefore signalled in advance of the virtual constriction to slow to a speed at which the risk of collision through spectacle observation is reduced and a signal expressly indicates the occurrence of an accident in the northbound lane so that observation motivated by the desire actually to determine whether there has been an accident is neutralised. Capsule I is signalled simultaneously to slow down. The same applies to the remaining Capsules A to H. Once the virtual constriction has been passed by a capsule, the vehicles therein are signalled immediately to increase speed.

Example 4 Two traffic capsules A and B are travelling on a highway as noted in Example 1.

The configuration and travel characteristics of the capsules are as set forth in Example 1 except that the computer, having determined the required vehicle module lengths for the vehicles in Capsule B, has determined that there is excess space between all the vehicles in Capsule B at the respective vehicle speeds within the capsule. The capsule thus fails to conform to the virtual model stored in the computer. The computer signals all the vehicles in Capsule B so that they increase speeds momentarily so as to close the inter-vehicle gaps so that the vehicle module lengths are contiguous. As a result Capsule B conforms itself to the virtual mode, in so doing decreasing in capsule length and distancing itself further from the following Capsule A. The computer signals car C1 in Capsule A to increase speed or to pull over to the centre lane. Car C1 accelerates and has pulled over to the centre lane of the highway within 0.5 mile. The balance of the capsule responds by the cars that were to the rear of the car C1 immediately accelerating to an increased speed, thus conforming to a virtual model for the capsule requiring it to progress at that speed. If the above-mentioned following cars, however, do not accelerate quickly enough, they will by signalled to do so (or to pull over to allow the other capsule members to do so and to advance), and equally should they close too much, they will be signalled to decelerate to compensate.

Example 5

A supercapsule progresses in an outside traffic lane of a three-lane carriageway at modest speed with the vehicles generally at safe distances. However, the centre lane is almost empty of traffic and in addition the vehicles in the outside lane repetitively close to unsafe inter-vehicular spacing. The computer signals to every fifth vehicle in successive 0.5 mile lengths of the supercapsule that it must change lane to the centre lane. On changing lane, the traffic density in the outer lane is substantially reduced enabling the vehicles therein increase speed, the vehicles in so doing closing inter-vehicular spacing and forming separate capsules. Those transferring to the centre lane rapidly increase speed and also form separate traffic capsules. The overall result is greater road use, increased flow of traffic, reduced driver frustration, reduced demands upon driver concentration and decrease accident potential.

Example 6 A triple lane carriageway has plural vehicles forming plural capsules in each lane. Capsule C in the outer lane proceeds efficiently and approximates its virtual model. It is seen, however, that as Capsule C proceeds it will be likely to need to be disturbed by commanding several vehicles to separate to the centre lane and that this may by prevented by excess traffic in that lane. The computer signals selected vehicles in Capsule C to separate to the centre lane but only after calculating the virtual model for a capsule in the centre lane which will accommodate this transfer, signalling selected vehicles in that latter-mentioned capsule to transfer to the inner lane and determining that the centre lane capsule has conformed to its virtual model.

Although the above examples refer to the computer signaling particular vehicles to change their highway travel characteristics, as mentioned above, it may be impossible for the computer to communicate with a particular vehicle, perhaps because that vehicle is not fitted with a transceiver, or even because the equipment in the vehicle is not turned on or is damaged. In some such circumstances, although it may be possible for the computer to signal one or more of the display devices to try to command the driver of the vehicle concerned to change one or more of the highway travel characteristics of the vehicle, it is possible that the vehicle will not change and cannot be

communicated with. In such circumstances, the computer will need to change the virtual model of efficient vehicle flow along the highway in order to compensate for such a vehicle, and, indeed, would also need to do so in circumstances where a driver of a vehicle that has been communicated with simply chooses, for whatever reason, to ignore the instructions.

It will be appreciated that although only one particular embodiment of the invention has been described in detail, various modifications and improvements can be made by a person skilled in the art without departing from the scope of the present invention. For example, although the embodiments of the invention describe the use of a cellular telecommunications network, such as GSM, it could, of course be a 4G (or UMTS) network, or a private network, for example a trunked network or any other type of suitable telecommunicatiosn network.

Alternative embodiments of the invention can be implemented as a computer program product for use with the central processing station, the computer program product being, for example, a series of computer instructions stored on a tangible data recording medium, such as a diskette, CD-ROM, ROM, or fixed disk, or embodied in a computer data signal, the signal being transmitted over a tangible medium or a wireless medium, for example microwave or infrared. The series of computer instructions can constitute all or part of the functionality described above, and can also be stored in any memory device, volatile or non- volatile, such as semiconductor, magnetic, optical or other memory device.