BACKGROUND OF THE INVENTION

[0001] This invention relates to an early warning system which is designed to alert road users about oncoming emergency vehicles and potentially dangerous situations.

[0002] Modern cities are characterized by a congested road network. In order to handle the many accidents, injuries, crimes and other events on this congested road network, a multitude of emergency management vehicles is required to traverse this network, often at high speed.

[0003] These emergency management vehicles rely on the foresight and awareness of other road users to respond appropriately, generally announcing their approach with a distinctive siren and flashing light system.

[0004] However, the siren and light system does not inform the road user of the nature of the emergency or the direction and speed at which the emergency vehicle is travelling, to enable the road user to arrive at the best response. Furthermore, a road user who is hard of hearing, or playing load music in their vehicle, may not be aware of the emergency vehicle at all.

[0005] An objective of the present invention is to provide road users with a warning device which at least addresses some of the aforementioned problems. SUMMARY OF INVENTION

[0006] "GPS unit" hereinafter refers to a module which is adapted to receive data packets from a plurality of GPS satellites and uses these data packets to ascertain position.

[0007] "GSM module" hereinafter refers to a module which allows bi-directional communication with other GSM modules over a GSM cellular network.

[0008] The invention provides a warning device which includes a GPS unit, which generates a navigation data stream, a GSM module, an RF transceiver for communication, via at least one radio frequency band, with other warning devices when the warning device is used in a system, and a microcontroller which receives the navigation data stream, forwards the data stream as a request to the GSM module for transmission over a GSM network and receives therefrom a response, and from the navigational data stream and the response is enabled to generate a positional data stream containing, at least, information on position, speed and direction of travel and nearest physical address of a vehicle to which the device is engaged, which positional data stream is then transmitted by the RF transceiver on the at least one radio frequency band.

[0009] The positional data stream may additionally include information on one or more of the following: three dimensional location, instantaneous and averaged speed and instantaneous and averaged direction of the vehicle. [0010] The device may include a memory unit. The memory unit may include a system data partition on which resides the following system data: information relating to the make, model and utility of the vehicle, a predefined alert zone radius, a set of dynamic alert zone parameters and a device designator for uniquely identifying the device.

[001 1] The set of dynamic alert zone parameters may include one or more of the following: human response time and type specific vehicle mass and braking capabilities.

[0012] The microcontroller may interrogate the memory unit to cause the transmission of the system data via the transceiver on the at least one radio frequency band.

[0013] Additionally, the memory unit may include a database partition comprising of a static portion and a volatile portion. The volatile portion of the database may be configured to store an interval of the positional data stream, continuously updated, in a circular buffer. The static portion of the database may be configured to store the positional data stream outside of the interval, dumped by the volatile portion

[0014] The device may be electronically connectable to the vehicle's on-board computer system to enable the microcontroller to interrogate, and receive therefrom, a stability data stream.

[0015] The stability data stream may include data on the rate and the force of an application of the brakes, a loss of tyre traction or a loss of brake function. [0016] The microcontroller may elect to cause the transmission of the stability data stream via the transceiver on the at least one radio frequency band.

[0017] The transceiver may communicate in a dual or multi-radio frequency band to maximise both broadcast distance and broadcast penetration.

[0018] The invention also provides for a warning system which includes at least a first warning device, of the kind described above, engaged with a first vehicle and a second device which includes at least a microcontroller, an RF transceiver for communication via at least one radio frequency band and a memory unit on which resides at least a predefined alert zone radius or dynamic alert zone parameters which includes human response time and type specific vehicle mass and braking capabilities and which microcontroller of the second device is enabled, on receipt of the positional data stream from the first warning device, to calculate a static alert zone from the predefined alert zone radius or a dynamic alert zone based on the dynamic alert zone parameters, and to determine if the first vehicle is within the static or the dynamic alert zone and, if so, to initiate a response.

[0019] The calculation of the dynamic alert zone by the microcontroller may include reference to the system data or the stability data stream of the first warning device.

[0020] The second device may be a stationary device which is engaged with a stationary structure such as, for example, a railway level crossing, a barrier across a road, a sharp or dangerous corner, a road island, a bridge, an uncontrolled road intersection, a high-accident zone, road-works or an offload zone. [0021] The second device may have on the memory unit information relating to the location of the stationary device and the identity or type of stationary structure.

[0022] The microcontroller of the second device may interrogate the memory unit and cause to transmit the information via the transceiver on the at least one radio frequency band.

[0023] The second device may be a second warning device of the kind described above, engaged with a second vehicle.

[0024] To calculate the static or the dynamic alert zone the microcontroller of the second warning device additionally may include its own positional, stability data streams or system data.

[0025] In the event that the GPS module of the second warning device loses GPS reception, the microcontroller is enabled to calculate, from the strength of a data stream received from the first warning device, the distance between the first and the second warning devices.

[0026] The first vehicle or the second vehicle may be a vehicle that is subject to a special road law or regulation, for example, a police vehicle, an ambulance or a fire truck.

[0027] The response may be for the second device to onwardly transmit the positional data stream of the first warning device. [0028] Additionally or alternatively the response may be an alarm response or a determination firstly of the probability of a collision with, or obstruction of, the first vehicle and, based on the probability, to then initiate the alarm response.

[0029] The alarm response may emanate from an alarm included in the second device or an alarm to which the second device is connectable. The alarm may be a visual, audible or one mechanical alarm.

[0030] Each of the at least first and second warning devices may include a user interface through which a user of the respective device may input data or instructions.

[0031] The user input may be a variation of the predefined alert zone by input of a different predefined alert zone radius.

[0032] Each of the devices may be activated, via input to the user interface, to broadcast a warning that the vehicle to which the device is engaged is experiencing a malfunction, for example loss of control through brake malfunction or loss of tyre traction.

[0033] The user interface may include a display screen on which the at least first and second vehicles and the stationary structure relative locations are displayed overlaid on a relevant map. BRI EF DESCRI PTION OF THE DRAWI NGS

[0034] The invention is further described by way of examples with reference to the accompanying drawings in which:

Figure 1 is a full front view of a warning unit according to a first aspect of the invention;

Figure 2 is a flow diagram showing communication within the warning unit of Figure 1 ;

Figure 3 diagrammatically represents an aerial view of motor vehicles in a vehicular warning system according to a second aspect of the invention ;

Figure 4 illustrates transmission and reception of signals in two distinct frequency bands between warning units operating in the vehicular warning system; and

Figure 5 illustrates the application of a dynamic alert zone between warning units operating in the vehicular warning system of Figure 3.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0035] Figure 1 of the accompanying drawings illustrates a warning unit 1 0 according to the invention which includes a body 12 which is mountable onto a vehicle or a stationary structure (see Figure 3 and Figure 5) and which houses a microcontroller 24, a memory bank 26, a GPS unit 28, a GSM module 34 and a radio frequency ("RF") transceiver unit 40. [0036] The unit 10 includes antennas 30, 36 and 42 which communicate through cables 32, 38 and 44 to the GPS unit 28, the GSM module 34 and the RF transceiver unit 40 respectively. The antennas 30, 36 and 42 are mounted on the body 1 2 to provide for reception and transmission of signals respectively to the GPS unit 28, and to from the GSM module 34 and the RF transceiver unit 40.

[0037] The unit 1 0 includes a touchscreen port 14 capable of interfacing the microcontroller 24 with a touchscreen display 16 via a touchscreen data cable 1 8. The touchscreen display 16 displays, as visually exemplified, the real time location 56A and speed and direction 56B of a first vehicle 56 to which the unit 10 is engaged, the real time location 58A and speed and direction 58B of a second vehicle 58 to which a second similar warning unit 10 is engaged, the location 59A of a stationary structure to which a third similar warning unit 1 0 is engaged , and an area 60 of possible intersection of the vehicles 56 and 58 and the stationary structure 59. The touchscreen port 14 and display 16 are optional and do not limit the invention .

[0038] Operationally, the units 1 0 on the first vehicle 56 and the second vehicle 58 communicate with each other to determine risk of collision or impediment between the two vehicles, and to raise an alarm to warn a driver of at least one of the vehicles. The units 1 0 of both vehicles also communicate with the third unit 1 0 mounted on the stationary structure 59 to be thereby warned by the third unit of the presence of the stationary structure 59 or the risk of collision or impediment of the vehicles 56 and 58 at the area 60. This is described in more detail in the description of Figures 3 and 5. [0039] Being similar, each warning unit 10 engaged with a vehicle operates as follows:

[0040] The microcontroller 24 is in communication with the GPS unit 28, the GSM module 34, the transceiver 40 and the memory bank 26. The memory bank 26 comprises a system data partition 21 and a database consisting of a volatile partition 23 and a static (non-volatile) partition 25. The static partition 25 is larger in memory capacity than the volatile partition 23, preferably five times more. The system data partition 21 stores at least one of vehicle identification data such as the make, model and utility of the vehicle, a predefined alert zone radius, dynamic alert zone parameters and a unique designator for the unit 10.

[0041] The GPS unit receives GPS location data through the antenna 30 and generates a GPS navigational data stream which includes location, speed of travel of the vehicle and direction of travel of the vehicle. This navigational data stream is received by the microcontroller 24, which formulates an information request data packet and sends it to the GSM module 34. The GSM module 34 transmits through the GSM antenna 36, the request data packet to the GSM network which accesses the internet and responds by sending back to the GSM module 34 a GSM data stream containing further information relating to the navigational data stream. Such further information is, for example, street names, landmarks and area names on and around which the warning unit 10 is located.

[0042] The microcontroller 24 receives the GSM data stream and forwards it to the transceiver 40, which then broadcasts this GSM data stream as a positional data stream through the transceiver antenna 42 on an RF band. The transceiver 40 transmits and receives the positional data stream using a novel simple, robust protocol that allows asynchronous communication between these other similar RF transceivers without the need for handshaking, device registries or address tables. The microcontroller 24 also interrogates the system data partition 21 , to receive system data and cause the system data to be broadcast by the transceiver 40.

[0043] Assuming that the warning unit which broadcasts the positional data stream is the unit of the first vehicle 56, the second warning unit on the second vehicle 58 and the third warning unit on the stationary structure 59 would, if within range of the broadcast, receive the positional data stream via their respective transceivers antennas 42, which data is then received by the respective transceivers 40 and eventually by the respective microcontrollers 24.

[0044] The microcontroller of the second unit of the second vehicle 58 would then compare the respective location, speed and direction of the first and second vehicles and determine the risk of collision or impediment with the first vehicle. Where the risk is high, the microcontroller would actuate an alarm.

[0045] The microcontroller 24 of the third unit on the stationary structure 59 would compare the location 56A and 58A, speed and direction of the vehicles 56B and 58B, and the location 59A of the stationary structure 59. Thereafter, the microcontroller 24 of the third unit would determine the risk of collision or impediment between the vehicles at area 60, and if the risk is high, actuate an alarm. [0046] The unit 10 engaged the stationary structure 59 works as has been described for the units on the vehicles 56 and 58, with the difference being that the unit on the stationary structure 59 does not require the GPS unit 28, the GPS antenna 30, the GSM module 34 and the GSM antenna 36 for functionality.

[0047] Each unit 10 is capable of receiving a positional data stream from another unit and re-broadcasting the positional data stream. This has the advantage of increasing the range of communication with other units which may be beyond a broadcast range.

[0048] As the warning unit 10 operates, information from a predetermined immediate past duration, for example, the last five minutes of operation, will be stored in the volatile partition 23. This means that at any point in time, the volatile partition 23 will contain all information for the immediate past five minutes. When a reportable event occurs which requires that a warning signal be broadcast and/or that an alarm be raised, the contents of the volatile partition 23 will be dumped into the static partition 25 of the database. This ensures preservation of data, which data can be extracted later on and used in investigations into causes of the reportable event.

[0049] The body 12 of the warning unit 10 further includes ports 20, 22, 46, 48, 50 and 52. Port 20 interfaces the unit 10 where necessary with a button array (not shown). The button array provides for human input to change or modify operation of the warning unit 10. Port 22 interfaces with a vehicular condition monitoring system (not shown) to provide input of vehicular conditions to the microcontroller 24. Port 46 interfaces with a visual alarm (not shown) in communication with the unit 0. Port 48 interfaces with an audio alarm (not shown) through audio alarm in communication with the unit 10. Port 50 interfaces with a mechanical alarm (not shown) in communication with the unit 1 0. Port 54 is a power point through which the warning unit 1 0 receives electrical power from any appropriate electrical power source through a power cable 52.

[0050] Figure 2 is a diagram illustrating communication within each unit 1 0. The microcontroller 24 with an RF transceiver driver 1 02 interfaces with the RF transceiver unit 40 which transmits and receives relevant information through the transceiver antenna 42, the information being, typically, warning signals 1 06. The RF transceiver driver 1 02 forwards incoming warning signals 1 06 to a message parser 1 08.

[0051] The message parser 108 dissects the incoming warning signals 1 06 as received from the RF transceiver driver 1 02 and outputs them as follows: GPS navigation data 1 1 0, to be input as a first argument to a GPS navigation data comparator 1 12; incoming address data 14, to be input as a first argument to an address data comparator 1 16; incoming device identification data 1 1 8, to be input as a first argument to a device identification data comparator 120; and incoming warning classification data 122, to be input as a first argument to a warning response comparator 124.

[0052] A GPS driver 126 interfaces with a GPS unit 28 and outputs the local GPS navigation data stream 1 30 which is tapped at point A. A GSM driver 1 32 interfaces with a GSM unit 34 to allow communication over the GSM network. The GSM driver 1 32 receives the local GPS navigation data stream 1 30, converts it to a local address data stream 1 36 through a method known in the art, and outputs the local address data stream 1 36, which is tapped at point B. A memory driver 1 38 interfaces with memory bank 26.

[0053] The GPS navigation data comparator 1 12 receives the local GPS navigation data stream 1 30 as a second argument and outputs a relativized GPS navigation data stream 142 which is tapped at point C. The address data comparator 1 16 receives the local address data stream 1 36 as a second argument and outputs the relativized address data stream 144 which is tapped at point D. The device identification data comparator 1 20 receives the local device identification data 146 from the memory driver 1 38 as a second argument and outputs the relativized device identification data stream 148. The warning response comparator 124 receives the relativized device identification data stream 148 as a second argument and outputs the relativized device versus warning data stream 1 50.

[0054] An alert zone multiplexer 1 52 receives and processes the relativized GPS navigation data stream 142 from point C, the relativized address data stream 144 from point D, and the relativized device versus warning data stream 1 50, to determine if an alarm should be generated and what the alarm contents should be. The alert zone multiplexer outputs signals to a warning signal generator 1 54, a visual alarm driver 1 56, an audio alarm driver 158, a mechanical alarm driver 1 60, and a touchscreen driver 1 62 which updates the touchscreen display 1 6 with the appropriate information. [0055] The touchscreen driver 162 further receives the local GPS navigation data stream 130, the local address data stream 136, the relativized GPS navigation data stream 142, and the relativized address data stream 144 from points A, B, C and D respectively, as additional parameters to appropriately update the touchscreen display 16.

[0056J The warning signal generator 1 54 receives user inputs from the touchscreen via the touchscreen driver 162, user inputs from the button array driver 166, vehicle condition monitoring signals 168 via the vehicle condition monitoring driver 170, the local GPS navigation data stream 130, and the local address data stream 1 36 from points A and B respectively, and uses them to determine if an outgoing warning signal or positional data stream 172 should be generated. The warning signal generator 1 54 can further receive a forwarded warning signal 1 74 from the alert zone multiplexer 52 which will be forwarded to other units 1 0 in communication.

[0057] The outgoing warning signal 172 generated by the warning signal generator 154 is sent to an outgoing message compiler 176 which compiles the message parameters into an appropriate message format and outputs the outgoing compiled warning signal 1 78 to the RF transceiver driver 102 which outputs the message to the RF transceiver unit 40.

[0058] The outgoing compiled warning signal 178 is then broadcast via the antenna 42, to be received by respective microcontrollers 24 in other similar units through each unit's respective antenna 42. Processing of the received signal then happens as described above. [0059] Figure 3 shows a first emergency vehicle 1 00, a second emergency vehicle 102, a third emergency vehicle 1 04, a first civilian vehicle 1 06, a second civilian vehicle 108, a third civilian vehicle 1 1 0, a fourth civilian vehicle 1 12, a fifth civilian vehicle 1 14, a sixth civilian vehicle 1 16, a seventh civilian vehicle 1 1 8 , an eighth civilian vehicle 120, a ninth civilian vehicle 1 22, a public transport vehicle 124 , and a point of interest 126, each equipped with warning units 10A - 10N respectively of the same construction and function as unit 10. Each unit 10A - 10N may therefore receive an incoming warning signal 1 06 from any other unit 1 0A - 1 0N, and send its respective outgoing warning signal 172 (i.e. its positional data stream).

[0060] The first emergency vehicle 100 is stationary after arriving at accident scene 128 involving the first and the second civilian vehicles 1 06 and 1 08 respectively. The second emergency vehicle 1 02 is travelling towards the accident scene 128 and is approaching the . third civilian vehicle 1 10 from the rear. The third emergency vehicle 104 is approaching the accident scene 128 and is travelling at high speed towards intersection 30. The fourth civilian vehicle 1 12 is travelling behind the third emergency vehicle 104. The fifth civilian vehicle 1 14 and the ninth civilian vehicle 122 are approaching the intersection 1 30 from opposite directions. The sixth civilian vehicle 1 16 has just driven past the public transport vehicle 1 24 that is offloading a passenger at a terminal (not shown) and the seventh civilian vehicle 1 18 is approaching the stationary public transport vehicle 124 from the rear. The eighth civilian vehicle 120 is travelling on a road parallel to that of the accident scene 1 28.

[0061] If a user of emergency vehicle 1 00 inputs a warning message into vehicle 100's unit 1 0A, the message will be broadcast to every other unit 1 0B - 1 0N. The location of the vehicle 1 00 will be detected by all units 10B - 10N . Supposing that the third civilian vehicle 1 1 0 reacts by braking sharply, the unit 1 0F in vehicle 1 1 0, being connected to the vehicle's condition monitoring system, will generate an outgoing warning signal 172 and broadcast it to all units 1 0A - 10E and 1 0G - 1 0N .

[0062] The eighth civilian vehicle 120 receives the warning signal through its unit 1 0K, but due to the fact that the positional stream indicates that said vehicle 120 is not on the same road and that the probability of intersection is low, the vehicle 120 is determined to be outside an alert zone and unit 10K will not be issued with an alarm response.

[0063] Warning signals 06 transmitted by vehicles close to point of interest 126 are received by the unit 1 0N , which reacts by broadcasting its own warning signal 1 06 and also raising an audio, visual or mechanical alarm to warn the general public, including pedestrians, cyclists and other motorists not equipped with a unit 10 in their vehicles.

[0064] As each unit 1 0A - 1 0N receives and generates warning signals 106, multiple classes of signals are received and each user is warned according to priority levels determined by the relativized GPS navigation data streams 142 of the respective vehicles.

[0065] Information which can be included in warnings includes, but is not limited to: temporary loss of control condition or data on stability of a vehicle such as emergency braking, excessive skidding, hydroplaning and brake failure; and temporary point of danger such as a train approaching a level crossing , a bus offloading passengers, an accident zone, an area of high danger such as a violent protest and a high density pedestrian zone.

[0066] Figure 4 uses the vehicles 1 00, 102, 104 and 1 06 of Figure 3 to illustrate transmission and reception of signals in two distinct frequency bands between the warning units 1 0A, 1 0B, 1 0C and 10D of each respective vehicle. For ease of reference, the units 1 0A - 10D have been shown, while the veh icles 1 00 - 1 06 have been left out.

[0067] The warning unit 1 0A transmits high frequency and low frequency signals to the warning units 0B, 1 0C and 1 0D which are all inherently capable of receiving such signals as described above. The high frequency signals have a coverage border 180B, while the low frequency signals have a coverage border 180A.

[0068] A clear line of sight W exists between units 10A and 1 0B. Lines of sight X and Y are blocked by a tree 1 82 and a building 1 84 respectively between unit 1 0A and 10D and between unit 10A and 10C.

[0069] Unit 1 0B is within the coverage border 1 80A and because of the clear line of sight W will receive the low frequency signals. However, unit 10B is outside the coverage border 80B and will not receive the high frequency signals from unit 10A.

[0070] Unit 10C is within the coverage border 1 80A, but because of the line of sight Y being obstructed by the building 1 84, the unit 1 0C will not receive the low frequency signals. The unit 1 0C is however inside the coverage border 1 80B and will receive the high frequency signals from unit 10A, as the high frequency signals will, because of their nature, go through the building 184.

[0071] Unit 10D is within the coverage border 180A, but because of the line of sight Y being obstructed by the tree 182, the unit 10D will not receive the low frequency signals. Also, the unit 10D is outside the coverage border 1 80B and will not receive the high frequency signals from unit 0A.

[0072] All signals may have multiple levels of severity. The microcontroller 24 in each therefore uses the operational information from the memory banks 26 to classify each signal received in terms of, at least, severity or urgency. The microcontroller 24 then raises an appropriate response, whether it be the broadcasting of a warning signal, or initiation of an audio, visual and/or mechanical alarm.

[0073] Warning signals 106 are generated only if a vehicle is within an alert zone. In a first aspect the alert zone is a predefined distance value. To illustrate this, it is assumed that the predefined distance value is 100 meters, and that a data stream is broadcast from a first device, for example the device 0A, and is received by a second device, for example the device 10B. If the second device 10B is determined to be within 100 meters of the first device, both devices are in each other's alert zones. An alarm response will therefore be initiated by the devices.

[0074] In a second aspect the alert zone is dynamic and is defined by dynamic parameters contained within the broadcast data stream of a broadcasting device and the dynamic parameters of a receiving device. [0075] These dynamic parameters are defined as, but not lim ited to, the distance between the devices, the relative direction of travel of the devices, the relative speed of the devices, the type, weight, and stopping distance of vehicle on which a device is mounted , the warning level of a broadcast data stream, human response time to an alarm response initiated by a device, and relative waypoint travel path of the first and/or second device. Upon receiving a broadcast data stream , a receiving device prioritizes and utilises its own dynamic parameters and those of the broadcasting device to determine a distance value to be assigned to the alert zone.

[0076] Therefore the dynamic alert zone is calculated, and can vary, on an individual basis for each receiving device.

[0077] Figure 5 illustrates the application of a dynamic alert zone, and shows an emergency vehicle 1 86, a first civilian vehicle 188, and a second civilian vehicle 1 90, each equipped with warning units 20A - 20C respectively and travelling in the same direction as indicated by the arrow. Each unit 20A - 20C is constructed as the warning unit 1 0. Like features therefore bear like reference.

[0078] Each unit 20A - 20C is able to receive an incoming warning signal 1 06 from any other unit 20A - 20C, and send its respective outgoing warning signal 1 72.

[0079] The emergency vehicle 1 86 is travelling towards an accident scene (accident scene not shown), and has passed the first civilian vehicle 1 88 and is therefore travelling faster than, and away from, the first civilian vehicle 1 88, and faster than and towards the second civilian vehicle 1 90, from the rear. [0080] When a user of the emergency vehicle 1 86 activates the warning functionality of the unit 20A engaged to the emergency vehicle 1 86, the message will be broadcast and received by the unit 20B and the unit 20C, as they are within receiving proximity to the emergency vehicle.

[0081] The broadcast warning signal from the unit 20A contains, but is not limited to, GPS latitude and longitude co-ordinates, bearing , speed and path of the emergency vehicle 1 86.

[0082] Upon receiving the warning signal transmitted by the unit 20A, the device 20B extracts the dynamic parameters contained within the received warning signal, through the relevant processes as shown in Figure 2, and calculates the parameters such as relative distance, relative bearing, relative speed and relative path , between the emergency vehicle 1 86 and the civilian vehicle 188.

[0083] The calculated relative parameters will show that the emergency vehicle 1 86 is within close proximity to the vehicle 1 88, travelling on a similar path and with similar direction. The parameters will also show that the first civilian vehicle 1 88 is to the rear of the emergency vehicle 1 86, and travelling at a lower speed compared to the emergency vehicle 1 86. From these calculations, and also considering that the first civilian vehicle 1 88 has adequate stopping time to avoid an incident should sudden braking be required , it is determined that a collision or obstruction between the two vehicles 188 and 186 is not likely to occur. As such, it is determined that an alarm response should not be issued to the user of the first civilian vehicle 1 88. [0084] Similarly, the warning signal transmitted by the unit 20A of the emergency vehicle 1 86 is received by the unit 20C of the second civilian vehicle 1 90. The device 20C extracts the dynamic parameters contained within the received warning signal, through the relevant processes as shown in Figure 2, and calculates the relative parameters between the emergency vehicle 1 86 and second civilian vehicle 1 90.

[0085] The calculated relative parameters will show that the emergency vehicle 1 86 is within close proximity to the civilian vehicle 1 90, travelling on a similar path and with similar direction , and that the second civilian vehicle 1 90 is in front of the emergency vehicle 186, and travelling at a lower speed. Therefore, the device 20C engaged to the second civilian vehicle 190 determines that a collision or obstruction, as a result of the presence of the emergency vehicle, is likely to occur and that an alarm response should therefore be issued to the user of the second civilian vehicle 190, in order to alert the user of the second civilian vehicle 1 90, of the approaching emergency vehicle 186. The device 20C then issues the alarm response.

[0086] The alarm response can be issued to the user of the second civilian vehicle 1 90 in the form of a visual, audible or mechanical alert, containing the relative direction of the approaching emergency vehicle 1 86 and suggested action for safe avoidance of the emergency vehicle 1 86.